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Ifrid E, Ouertatani-Sakouhi H, Jauslin T, Kicka S, Chiriano G, Harrison CF, Hilbi H, Scapozza L, Soldati T, Cosson P. 5-ethyl-2'-deoxyuridine fragilizes Klebsiella pneumoniae outer wall and facilitates intracellular killing by phagocytic cells. PLoS One 2022; 17:e0269093. [PMID: 36315510 PMCID: PMC9621411 DOI: 10.1371/journal.pone.0269093] [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: 06/11/2021] [Accepted: 05/14/2022] [Indexed: 01/24/2023] Open
Abstract
Klebsiella pneumoniae is the causative agent of a variety of severe infections. Many K. pneumoniae strains are resistant to multiple antibiotics, and this situation creates a need for new antibacterial molecules. K. pneumoniae pathogenicity relies largely on its ability to escape phagocytosis and intracellular killing by phagocytic cells. Interfering with these escape mechanisms may allow to decrease bacterial virulence and to combat infections. In this study, we used Dictyostelium discoideum as a model phagocyte to screen a collection of 1,099 chemical compounds. Phg1A KO D. discoideum cells cannot feed upon K. pneumoniae bacteria, unless bacteria bear mutations decreasing their virulence. We identified 3 non-antibiotic compounds that restored growth of phg1A KO cells on K. pneumoniae, and we characterized the mode of action of one of them, 5-ethyl-2'-deoxyuridine (K2). K2-treated bacteria were more rapidly killed in D. discoideum phagosomes than non-treated bacteria. They were more sensitive to polymyxin and their outer membrane was more accessible to a hydrophobic fluorescent probe. These results suggest that K2 acts by rendering the membrane of K. pneumoniae accessible to antibacterial effectors. K2 was effective on three different K. pneumoniae strains, and acted at concentrations as low as 3 μM. K2 has previously been used to treat viral infections but its precise molecular mechanism of action in K. pneumoniae remains to be determined.
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Affiliation(s)
- Estelle Ifrid
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
| | - Hajer Ouertatani-Sakouhi
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
| | - Tania Jauslin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
| | - Sebastien Kicka
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Gianpaolo Chiriano
- Pharmaceutical Biochemistry, School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
| | - Christopher F. Harrison
- Max von Pettenkofer Institute, Department of Medicine, Ludwig-Maximilians University Munich, Munich, Germany
| | - Hubert Hilbi
- Institute of Medical Microbiology, Department of Medicine, University of Zürich, Zürich, Switzerland
| | - Leonardo Scapozza
- Pharmaceutical Biochemistry, School of Pharmaceutical Sciences, University of Geneva, Geneva, 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, Centre Médical Universitaire, Geneva, Switzerland
- * E-mail:
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Galindo A, Javier-Reyna R, García-Rivera G, Bañuelos C, Montaño S, Ortega-Lopez J, Chávez-Munguía B, Salazar-Villatoro L, Orozco E. EhVps23: A Component of ESCRT-I That Participates in Vesicular Trafficking and Phagocytosis of Entamoeba histolytica. Front Cell Infect Microbiol 2021; 11:770759. [PMID: 34778112 PMCID: PMC8588831 DOI: 10.3389/fcimb.2021.770759] [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] [Received: 09/04/2021] [Accepted: 10/12/2021] [Indexed: 11/26/2022] Open
Abstract
The endosomal sorting complex required for transport (ESCRT) is formed by ESCRT-0, ESCRT-I, ESCRT-II, ESCRT-III complexes, and accessory proteins. It conducts vesicular trafficking in eukaryotes through the formation of vesicles and membrane fission and fusion events. The trophozoites of Entamoeba histolytica, the protozoan responsible for human amoebiasis, presents an active membrane movement in basal state that increases during phagocytosis and tissue invasion. ESCRT-III complex has a pivotal role during these events, but ESCRT-0, ESCRT-I and ESCRT-II have been poorly studied. Here, we unveiled the E. histolytica ESCRT-I complex and its implication in vesicular trafficking and phagocytosis, as well as the molecular relationships with other phagocytosis-involved molecules. We found a gene encoding for a putative EhVps23 protein with the ubiquitin-binding and Vps23 core domains. In basal state, it was in the plasma membrane, cytoplasmic vesicles and multivesicular bodies, whereas during phagocytosis it was extensively ubiquitinated and detected in phagosomes and connected vesicles. Docking analysis, immunoprecipitation assays and microscopy studies evidenced its interaction with EhUbiquitin, EhADH, EhVps32 proteins, and the lysobisphosphatidic acid phospholipid. The knocking down of the Ehvps23 gene resulted in lower rates of phagocytosis. Our results disclosed the concert of finely regulated molecules and vesicular structures participating in vesicular trafficking-related events with a pivotal role of EhVps23.
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Affiliation(s)
- Ausencio Galindo
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, Mexico
| | - Rosario Javier-Reyna
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, Mexico
| | - Guillermina García-Rivera
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, Mexico
| | - Cecilia Bañuelos
- Programa Transdisciplinario en Desarrollo Científico y Tecnológico para la Sociedad, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, Mexico
| | - Sarita Montaño
- Laboratorio de Bioinformática y Simulación Molecular, Facultad de Ciencias Químico-Biológicas, Universidad Autónoma de Sinaloa, Sinaloa, Mexico
| | - Jaime Ortega-Lopez
- Departamento de Biotecnología y Bioingeniería, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, Mexico
| | - Bibiana Chávez-Munguía
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, Mexico
| | - Lizbeth Salazar-Villatoro
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, Mexico
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, Mexico
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3
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Wang S, Jagadesan P, Sun H, Hu R, Li Z, Huang Y, Liu L, Wang S, Younus M, Schanze KS. Fluorescence Imaging of Mammalian Cells with Cationic Conjugated Polyelectrolytes. CHEMPHOTOCHEM 2020. [DOI: 10.1002/cptc.202000192] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Shanshan Wang
- Department of Chemistry University of Florida Gainesville Florida 32611-7200 USA
| | - Pradeepkumar Jagadesan
- Department of Chemistry University of Texas at San Antonio One UTSA San Antonio TX, 78249 USA
| | - Han Sun
- Department of Chemistry University of Texas at San Antonio One UTSA San Antonio TX, 78249 USA
| | - Rong Hu
- Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Zhiliang Li
- Department of Chemistry University of Florida Gainesville Florida 32611-7200 USA
| | - Yun Huang
- Department of Chemistry University of Florida Gainesville Florida 32611-7200 USA
| | - Libing Liu
- Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Shu Wang
- Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Muhammad Younus
- Department of Chemistry University of Texas at San Antonio One UTSA San Antonio TX, 78249 USA
| | - Kirk S. Schanze
- Department of Chemistry University of Florida Gainesville Florida 32611-7200 USA
- Department of Chemistry University of Texas at San Antonio One UTSA San Antonio TX, 78249 USA
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4
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Durocher AF, Gagné-Thivierge C, Charette SJ. Various dictyostelids from the environment can produce multilamellar bodies. Can J Microbiol 2020; 66:679-688. [PMID: 32735763 DOI: 10.1139/cjm-2020-0187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Multilamellar bodies (MLBs), structures composed of concentric membrane layers, are known to be produced by different protozoa, including species of ciliates, free-living amoebae, and Dictyostelium discoideum social amoebae. Initially believed to be metabolic waste, potential roles like cell communication and food storage have been suggested for D. discoideum MLBs, which could be useful for the multicellular development of social amoebae and as a food source. However, among dictyostelids, this phenomenon has only been observed with D. discoideum, and mainly with laboratory strains grown in axenic conditions. It was thought that other social amoebae may also produce MLBs. Four environmental social amoeba isolates were characterized. All strains belong to the Dictyostelium genus, including some likely to be Dictyostelium giganteum. They have distinctive phenotypes comprising their growth rate on Klebsiella aerogenes lawns and the morphology of their fruiting bodies. They all produce MLBs like those produced by a D. discoideum laboratory strain when grown on K. aerogenes lawns, as revealed by analysis using the H36 antibody in epifluorescence microscopy as well as by transmission electron microscopy. Consequently, this study shows that MLBs are produced by various dictyostelid species, which further supports a role for MLBs in the lifestyle of amoebae.
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Affiliation(s)
- Alicia F Durocher
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médicine, Québec, QC G1V 0A6, Canada.,Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, 2725, chemin Sainte-Foy, Québec, QC G1V 4G5, Canada.,Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045, avenue de la Médicine, Québec, QC G1V 0A6, Canada
| | - Cynthia Gagné-Thivierge
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médicine, Québec, QC G1V 0A6, Canada.,Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, 2725, chemin Sainte-Foy, Québec, QC G1V 4G5, Canada.,Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045, avenue de la Médicine, Québec, QC G1V 0A6, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médicine, Québec, QC G1V 0A6, Canada.,Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, 2725, chemin Sainte-Foy, Québec, QC G1V 4G5, Canada.,Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045, avenue de la Médicine, Québec, QC G1V 0A6, Canada
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5
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Abstract
All animals are associated with microorganisms; hence, host-microbe interactions are of fundamental importance for life on earth. However, we know little about the molecular basis of these interactions. Therefore, we studied the deep-sea Riftia pachyptila symbiosis, a model association in which the tubeworm host is associated with only one phylotype of endosymbiotic bacteria and completely depends on this sulfur-oxidizing symbiont for nutrition. Using a metaproteomics approach, we identified both metabolic interaction processes, such as substrate transfer between the two partners, and interactions that serve to maintain the symbiotic balance, e.g., host efforts to control the symbiont population or symbiont strategies to modulate these host efforts. We suggest that these interactions are essential principles of mutualistic animal-microbe associations. The deep-sea tubeworm Riftia pachyptila lacks a digestive system but completely relies on bacterial endosymbionts for nutrition. Although the symbiont has been studied in detail on the molecular level, such analyses were unavailable for the animal host, because sequence information was lacking. To identify host-symbiont interaction mechanisms, we therefore sequenced the Riftia transcriptome, which served as a basis for comparative metaproteomic analyses of symbiont-containing versus symbiont-free tissues, both under energy-rich and energy-limited conditions. Our results suggest that metabolic interactions include nutrient allocation from symbiont to host by symbiont digestion and substrate transfer to the symbiont by abundant host proteins. We furthermore propose that Riftia maintains its symbiont by protecting the bacteria from oxidative damage while also exerting symbiont population control. Eukaryote-like symbiont proteins might facilitate intracellular symbiont persistence. Energy limitation apparently leads to reduced symbiont biomass and increased symbiont digestion. Our study provides unprecedented insights into host-microbe interactions that shape this highly efficient symbiosis.
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6
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Lammel T, Mackevica A, Johansson BR, Sturve J. Endocytosis, intracellular fate, accumulation, and agglomeration of titanium dioxide (TiO 2) nanoparticles in the rainbow trout liver cell line RTL-W1. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:15354-15372. [PMID: 30929178 PMCID: PMC6529399 DOI: 10.1007/s11356-019-04856-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 03/13/2019] [Indexed: 06/01/2023]
Abstract
There is increasing evidence that titanium dioxide (TiO2) nanoparticles (NPs) present in water or diet can be taken up by fish and accumulate in internal organs including the liver. However, their further fate in the organ is unknown. This study provides new insights into the interaction, uptake mechanism, intracellular trafficking, and fate of TiO2 NPs (Aeroxide® P25) in fish liver parenchymal cells (RTL-W1) in vitro using high-resolution transmission electron microscopy (TEM) and single particle inductively coupled plasma mass spectrometry (spICP-MS) as complementary analytical techniques. The results demonstrate that following their uptake via caveolae-mediated endocytosis, TiO2 NPs were trafficked through different intracellular compartments including early endosomes, multivesicular bodies, and late endosomes/endo-lysosomes, and eventually concentrated inside multilamellar vesicles. TEM and spICP-MS results provide evidence that uptake was nano-specific. Only NPs/NP agglomerates of a specific size range (~ 30-100 nm) were endocytosed; larger agglomerates were excluded from uptake and remained located in the extracellular space/exposure medium. NP number and mass inside cells increased linearly with time and was associated with an increase in particle diameter suggesting intracellular agglomeration/aggregation. No alterations in the expression of genes regulated by the redox balance-sensitive transcription factor Nrf-2 including superoxide dismutase, glutamyl cysteine ligase, glutathione synthetase, glutathione peroxidase, and glutathione S-transferase were observed. This shows that, despite the high intracellular NP burden (~ 3.9 × 102 ng Ti/mg protein after 24 h) and NP-interaction with mitochondria, cellular redox homeostasis was not significantly affected. This study contributes to a better mechanistic understanding of in vitro particokinetics as well as the potential fate and effects of TiO2 NPs in fish liver cells.
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Affiliation(s)
- Tobias Lammel
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 463, 413 90, Göteborg, Sweden.
| | - Aiga Mackevica
- DTU Environment, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Bengt R Johansson
- The Electron Microscopy Unit, Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, 405 30, Göteborg, Sweden
| | - Joachim Sturve
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 463, 413 90, Göteborg, Sweden
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7
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The fate of multilamellar bodies produced and secreted by Dictyostelium discoideum amoebae. Eur J Cell Biol 2017; 96:767-773. [DOI: 10.1016/j.ejcb.2017.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 10/12/2017] [Accepted: 10/13/2017] [Indexed: 11/19/2022] Open
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8
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Mathavarajah S, Flores A, Huber RJ. Dictyostelium discoideum
: A Model System for Cell and Developmental Biology. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/cpet.15] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | - Ana Flores
- Department of Biology, Trent University Peterborough Ontario Canada
| | - Robert J. Huber
- Department of Biology, Trent University Peterborough Ontario Canada
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9
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Mycobacterium marinum antagonistically induces an autophagic response while repressing the autophagic flux in a TORC1- and ESX-1-dependent manner. PLoS Pathog 2017; 13:e1006344. [PMID: 28414774 PMCID: PMC5407849 DOI: 10.1371/journal.ppat.1006344] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 04/27/2017] [Accepted: 04/11/2017] [Indexed: 12/18/2022] Open
Abstract
Autophagy is a eukaryotic catabolic process also participating in cell-autonomous defence. Infected host cells generate double-membrane autophagosomes that mature in autolysosomes to engulf, kill and digest cytoplasmic pathogens. However, several bacteria subvert autophagy and benefit from its machinery and functions. Monitoring infection stages by genetics, pharmacology and microscopy, we demonstrate that the ESX-1 secretion system of Mycobacterium marinum, a close relative to M. tuberculosis, upregulates the transcription of autophagy genes, and stimulates autophagosome formation and recruitment to the mycobacteria-containing vacuole (MCV) in the host model organism Dictyostelium. Antagonistically, ESX-1 is also essential to block the autophagic flux and deplete the MCV of proteolytic activity. Activators of the TORC1 complex localize to the MCV in an ESX-1-dependent manner, suggesting an important role in the manipulation of autophagy by mycobacteria. Our findings suggest that the infection by M. marinum activates an autophagic response that is simultaneously repressed and exploited by the bacterium to support its survival inside the MCV. One of the cell-autonomous defence pathways against intracellular pathogens is autophagy, an ancestral eukaryotic process surprisingly conserved throughout evolution. Recent studies have highlighted contradictory roles for autophagy during mycobacterial infection. Whereas some studies revealed a role for autophagy to control intracellular bacterial growth, others brought evidence that mycobacteria somehow inhibit autophagic killing. Here, we demonstrate for the first time that Mycobacterium marinum induces both an early autophagic response and its simultaneous repression by blocking the autophagic digestion. This antagonistic manipulation of autophagy is dependent on a functional ESX-1-secretion system, which secretes the membrane-damaging factor ESAT-6, proposed to participate in the perforation of the M. marinum-containing vacuole (MCV). We show here that these membrane damages activate the formation of autophagosomes and their recruitment to the MCV. However, M. marinum also utilizes its ESX-1 secretion system to avoid killing inside autolysosomes by blocking the autophagic flux. In addition, we bring evidence that this manipulation of autophagy is orchestrated via the regulation of TORC1, the major eukaryotic kinase complex controlling nutrient-sensing and cell metabolism.
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10
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Identification of Proteins Associated with Multilamellar Bodies Produced by Dictyostelium discoideum. PLoS One 2016; 11:e0158270. [PMID: 27340834 PMCID: PMC4920372 DOI: 10.1371/journal.pone.0158270] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/13/2016] [Indexed: 02/05/2023] Open
Abstract
Dictyostelium discoideum amoebae produce and secrete multilamellar bodies (MLBs) when fed digestible bacteria. The aim of the present study was to elucidate the proteic content of MLBs. The lipid composition of MLBs is mainly amoebal in origin, suggesting that MLB formation is a protozoa-driven process that could play a significant role in amoebal physiology. We identified four major proteins on purified MLBs using mass spectrometry in order to better understand the molecular mechanisms governing MLB formation and, eventually, to elucidate the true function of MLBs. These proteins were SctA, PhoPQ, PonC and a protein containing a cytidine/deoxycytidylate deaminase (CDD) zinc-binding region. SctA is a component of pycnosomes, which are membranous materials that are continuously secreted by amoebae. The presence of SctA on MLBs was confirmed by immunofluorescence and Western blotting using a specific anti-SctA antibody. The CDD protein may be one of the proteins recognized by the H36 antibody, which was used as a MLB marker in a previous study. The function of the CDD protein is unknown. Immunofluorescence and flow cytometric analyses confirmed that the H36 antibody is a better marker of MLBs than the anti-SctA antibody. This study is an additional step to elucidate the potential role of MLBs and revealed that only a small set of proteins appeared to be present on MLBs.
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11
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Pycnosomes: Condensed Endosomal Structures Secreted by Dictyostelium Amoebae. PLoS One 2016; 11:e0154875. [PMID: 27187592 PMCID: PMC4871501 DOI: 10.1371/journal.pone.0154875] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/20/2016] [Indexed: 11/19/2022] Open
Abstract
Dictyostelium discoideum has been used largely as a model organism to study the organization and function of the endocytic pathway. Here we describe dense structures present in D. discoideum endocytic compartments, which we named pycnosomes. Pycnosomes are constitutively secreted in the extracellular medium, from which they can be recovered by differential centrifugation. We identified the most abundant protein present in secreted pycnosomes, that we designated SctA. SctA defines a new family of proteins with four members in D. discoideum, and homologous proteins in other protists and eumetazoa. We developed a monoclonal antibody specific for SctA and used it to further characterize secreted and intracellular pycnosomes. Within cells, immunofluorescence as well as electron microscopy identified pycnosomes as SctA-enriched dense structures in the lumen of endocytic compartments. Pycnosomes are occasionally seen in continuity with intra-endosomal membranes, particularly in U18666A-treated cells where intraluminal budding is highly enhanced. While the exact nature, origin and cellular function of pycnosomes remain to be established, this study provides a first description of these structures as well as a characterization of reagents that can be used for further studies.
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12
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Robertson P, Abdelhady H, Garduño RA. The many forms of a pleomorphic bacterial pathogen-the developmental network of Legionella pneumophila. Front Microbiol 2014; 5:670. [PMID: 25566200 PMCID: PMC4273665 DOI: 10.3389/fmicb.2014.00670] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 11/18/2014] [Indexed: 01/18/2023] Open
Abstract
Legionella pneumophila is a natural intracellular bacterial parasite of free-living freshwater protozoa and an accidental human pathogen that causes Legionnaires' disease. L. pneumophila differentiates, and does it in style. Recent experimental data on L. pneumophila's differentiation point at the existence of a complex network that involves many developmental forms. We intend readers to: (i) understand the biological relevance of L. pneumophila's forms found in freshwater and their potential to transmit Legionnaires' disease, and (ii) learn that the common depiction of L. pneumophila's differentiation as a biphasic developmental cycle that alternates between a replicative and a transmissive form is but an oversimplification of the actual process. Our specific objectives are to provide updates on the molecular factors that regulate L. pneumophila's differentiation (Section The Differentiation Process and Its Regulation), and describe the developmental network of L. pneumophila (Section Dissecting Lp's Developmental Network), which for clarity's sake we have dissected into five separate developmental cycles. Finally, since each developmental form seems to contribute differently to the human pathogenic process and the transmission of Legionnaires' disease, readers are presented with a challenge to develop novel methods to detect the various L. pneumophila forms present in water (Section Practical Implications), as a means to improve our assessment of risk and more effectively prevent legionellosis outbreaks.
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Affiliation(s)
- Peter Robertson
- Department of Microbiology and Immunology, Dalhousie University Halifax, NS, Canada
| | - Hany Abdelhady
- Department of Microbiology and Immunology, Dalhousie University Halifax, NS, Canada
| | - Rafael A Garduño
- Department of Microbiology and Immunology, Dalhousie University Halifax, NS, Canada ; Division of Infectious Diseases, Department of Medicine, Dalhousie University Halifax, NS, Canada
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13
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Denoncourt AM, Paquet VE, Charette SJ. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria. Front Microbiol 2014; 5:240. [PMID: 24904553 PMCID: PMC4033053 DOI: 10.3389/fmicb.2014.00240] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/02/2014] [Indexed: 11/17/2022] Open
Abstract
Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.
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Affiliation(s)
- Alix M Denoncourt
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada
| | - Valérie E Paquet
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada ; Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval Quebec City, QC, Canada
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14
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Lima WC, Balestrino D, Forestier C, Cosson P. Two distinct sensing pathways allow recognition of Klebsiella pneumoniae by Dictyostelium amoebae. Cell Microbiol 2013; 16:311-23. [PMID: 24128258 PMCID: PMC4303882 DOI: 10.1111/cmi.12226] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/24/2013] [Accepted: 10/07/2013] [Indexed: 12/24/2022]
Abstract
Recognition of bacteria by metazoans is mediated by receptors that recognize different types of microorganisms and elicit specific cellular responses. The soil amoebae Dictyostelium discoideum feeds upon a variable mixture of environmental bacteria, and it is expected to recognize and adapt to various food sources. To date, however, no bacteria-sensing mechanisms have been described. In this study, we isolated a Dictyostelium mutant (fspA KO) unable to grow in the presence of non-capsulated Klebsiella pneumoniae bacteria, but growing as efficiently as wild-type cells in the presence of other bacteria, such as Bacillus subtilis. fspA KO cells were also unable to respond to K. pneumoniae and more specifically to bacterially secreted folate in a chemokinetic assay, while they responded readily to B. subtilis. Remarkably, both WT and fspA KO cells were able to grow in the presence of capsulated LM21 K. pneumoniae, and responded to purified capsule, indicating that capsule recognition may represent an alternative, FspA-independent mechanism for K. pneumoniae sensing. When LM21 capsule synthesis genes were deleted, growth and chemokinetic response were lost for fspA KO cells, but not for WT cells. Altogether, these results indicate that Dictyostelium amoebae use specific recognition mechanisms to respond to different K. pneumoniae elements.
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Affiliation(s)
- Wanessa C Lima
- Department for Cell Physiology and Metabolism, Centre Medical Universitaire, University of Geneva, 1 rue Michel Servet, 1211, Geneva 4, Switzerland
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15
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Lipid composition of multilamellar bodies secreted by Dictyostelium discoideum reveals their amoebal origin. EUKARYOTIC CELL 2013; 12:1326-34. [PMID: 23748431 DOI: 10.1128/ec.00107-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
When they are fed with bacteria, Dictyostelium discoideum amoebae produce and secrete multilamellar bodies (MLBs), which are composed of membranous material. It has been proposed that MLBs are a waste disposal system that allows D. discoideum to eliminate undigested bacterial remains. However, the real function of MLBs remains unknown. Determination of the biochemical composition of MLBs, especially lipids, represents a way to gain information about the role of these structures. To allow these analyses, a protocol involving various centrifugation procedures has been developed to purify secreted MLBs from amoeba-bacterium cocultures. The purity of the MLB preparation was confirmed by transmission electron microscopy and by immunofluorescence using H36, an antibody that binds to MLBs. The lipid and fatty acid compositions of pure MLBs were then analyzed by high-performance thin-layer chromatography (HPTLC) and gas chromatography (GC), respectively, and compared to those of amoebae as well as bacteria used as a food source. While the bacteria were devoid of phosphatidylcholine (PC) and phosphatidylinositol (PI), these two polar lipid species were major classes of lipids in MLBs and amoebae. Similarly, the fatty acid composition of MLBs and amoebae was characterized by the presence of polyunsaturated fatty acids, while cyclic fatty acids were found only in bacteria. These results strongly suggest that the lipids constituting the MLBs originate from the amoebal metabolism rather than from undigested bacterial membranes. This opens the possibility that MLBs, instead of being a waste disposal system, have unsuspected roles in D. discoideum physiology.
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Maniak M. Dictyostelium as a model for human lysosomal and trafficking diseases. Semin Cell Dev Biol 2010; 22:114-9. [PMID: 21056680 DOI: 10.1016/j.semcdb.2010.11.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 10/27/2010] [Accepted: 11/01/2010] [Indexed: 11/17/2022]
Abstract
Dictyostelium cells are genetically haploid and therefore easily analyzed for mutant phenotypes. In the past, many tools and molecular markers have been developed for a quantitative and qualitative analysis of the endocytic pathway in these amoebae. This review outlines parallels and discrepancies between mutants in Dictyostelium, the corresponding mammalian cells and the symptoms of human patients affected by lysosomal and trafficking defects. Situations where knowledge from Dictyostelium may potentially help understand human disease and vice versa are also addressed.
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Affiliation(s)
- Markus Maniak
- Abteilung Zellbiologie, Universität Kassel, Kassel, Germany.
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17
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Valero RA, Oeste CL, Stamatakis K, Ramos I, Herrera M, Boya P, Pérez-Sala D. Structural determinants allowing endolysosomal sorting and degradation of endosomal GTPases. Traffic 2010; 11:1221-33. [PMID: 20573066 DOI: 10.1111/j.1600-0854.2010.01091.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rapid control of protein degradation is usually achieved through the ubiquitin-proteasome pathway. We recently found that the short-lived GTPase RhoB is degraded in lysosomes. Moreover, the fusion of the RhoB C-terminal sequence CINCCKVL, containing the isoprenylation and palmitoylation sites, to other proteins directs their sorting into multivesicular bodies (MVBs) and rapid lysosomal degradation. Here, we show that this process is highly specific for RhoB. Alteration of late endosome lipid dynamics produced the accumulation of RhoB, but not of other endosomal GTPases, including Rab5, Rab7, Rab9 or Rab11, into enlarged MVB. Other isoprenylated and bipalmitoylated GTPases, such as H-Ras, Rap2A, Rap2B and TC10, were not accumulated into MVB and were stable. Remarkably, although TC10, which is highly homologous to RhoB, was stable, a sequence derived from its C-terminus (CINCCLIT) elicited MVB sorting and degradation of a green fluorescent protein (GFP)-chimeric protein. This led us to identify a cluster of basic amino acids (KKH) in the TC10 hypervariable region, constituting a secondary signal potentially involved in electrostatic interactions with membrane lipids. Mutation of this cluster allowed TC10 MVB sorting and degradation, whereas inserting it into RhoB hypervariable region rescued this protein from its lysosomal degradation pathway. These findings define a highly specific structural module for entering the MVB pathway and rapid lysosomal degradation.
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Affiliation(s)
- Ruth A Valero
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
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18
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Dieckmann R, von Heyden Y, Kistler C, Gopaldass N, Hausherr S, Crawley SW, Schwarz EC, Diensthuber RP, Côté GP, Tsiavaliaris G, Soldati T. A myosin IK-Abp1-PakB circuit acts as a switch to regulate phagocytosis efficiency. Mol Biol Cell 2010; 21:1505-18. [PMID: 20200225 PMCID: PMC2861610 DOI: 10.1091/mbc.e09-06-0485] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Actin dynamics and myosin (Myo) contractile forces are necessary for formation and closure of the phagocytic cup. In Dictyostelium, the actin-binding protein Abp1 and myosin IK are enriched in the closing cup and especially at an actin-dense constriction furrow formed around the neck of engulfed budded yeasts. This phagocytic furrow consists of concentric overlapping rings of MyoK, Abp1, Arp3, coronin, and myosin II, following an order strikingly reminiscent of the overall organization of the lamellipodium of migrating cells. Mutation analyses of MyoK revealed that both a C-terminal farnesylation membrane anchor and a Gly-Pro-Arg domain that interacts with profilin and Abp1 were necessary for proper localization in the furrow and efficient phagocytosis. Consequently, we measured the binding affinities of these interactions and unraveled further interactions with profilins, dynamin A, and PakB. Due to the redundancy of the interaction network, we hypothesize that MyoK and Abp1 are restricted to regulatory roles and might affect the dynamic of cup progression. Indeed, phagocytic uptake was regulated antagonistically by MyoK and Abp1. MyoK is phosphorylated by PakB and positively regulates phagocytosis, whereas binding of Abp1 negatively regulates PakB and MyoK. We conclude that a MyoK-Abp1-PakB circuit acts as a switch regulating phagocytosis efficiency of large particles.
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Affiliation(s)
- Régis Dieckmann
- Départment de Biochimie, Faculté des Sciences, Université de Genève, Sciences II, CH-1211-Genève-4, Switzerland
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19
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Effect of starvation on the endocytic pathway in Dictyostelium cells. EUKARYOTIC CELL 2010; 9:387-92. [PMID: 20097741 DOI: 10.1128/ec.00285-09] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Dictyostelium discoideum amoebae have been used extensively to study the structure and dynamics of the endocytic pathway. Here, we show that while the general structure of the endocytic pathway is maintained in starved cells, its dynamics rapidly slow down. In addition, analysis of apm3 and lvsB mutants reveals that the functional organization of the endocytic pathway is profoundly modified upon starvation. Indeed, in these mutant cells, some of the defects observed in rich medium persist in starved cells, notably an abnormally slow transfer of endocytosed material between endocytic compartments. Other parameters, such as endocytosis of the fluid phase or the rate of fusion of postlysosomes to the cell surface, vary dramatically upon starvation. Studying the endocytic pathway in starved cells can provide a different perspective, allowing the primary (invariant) defects resulting from specific mutations to be distinguished from their secondary (conditional) consequences.
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20
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Koonce MP, Gräf R. Dictyostelium discoideum: a model system for ultrastructural analyses of cell motility and development. Methods Cell Biol 2010; 96:197-216. [PMID: 20869524 DOI: 10.1016/s0091-679x(10)96009-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Dictyostelium occupies an interesting niche in the grand scheme of model organisms. On the one hand, it is a compact, highly motile single cell that presents numerous opportunities to investigate the fundamental mechanisms of signal transduction, cell movement, and pathogen infection. However, upon starvation, individual cells enter a developmental pathway that involves cell aggregation, cell-cell adhesion, pattern formation, and differentiation. Thus, Dictyostelium is also well known as a basic model for studying developmental processes. Electron microscopy (EM) has played a large role in both the unicellular and the multicellular life stages, for example, providing image detail for structure/function relationships of cytoskeletal proteins, the deposition of cellulose fibrils in maturing spores, and the identification of intercellular junctional complexes. Powerful combinations of robust molecular genetic tools, high-resolution light microscopy, and EM methods make this organism an attractive model for imaging dynamic cell processes. This chapter serves to highlight the past and current EM approaches that have advanced our understanding of how cells and proteins function.
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Affiliation(s)
- Michael P Koonce
- Division of Translational Medicine, Wadsworth Center, Albany, New York 12201-0509, USA
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Pérez-Sala D, Boya P, Ramos I, Herrera M, Stamatakis K. The C-terminal sequence of RhoB directs protein degradation through an endo-lysosomal pathway. PLoS One 2009; 4:e8117. [PMID: 19956591 PMCID: PMC2780327 DOI: 10.1371/journal.pone.0008117] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Accepted: 11/05/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Protein degradation is essential for cell homeostasis. Targeting of proteins for degradation is often achieved by specific protein sequences or posttranslational modifications such as ubiquitination. METHODOLOGY/PRINCIPAL FINDINGS By using biochemical and genetic tools we have monitored the localization and degradation of endogenous and chimeric proteins in live primary cells by confocal microscopy and ultra-structural analysis. Here we identify an eight amino acid sequence from the C-terminus of the short-lived GTPase RhoB that directs the rapid degradation of both RhoB and chimeric proteins bearing this sequence through a lysosomal pathway. Elucidation of the RhoB degradation pathway unveils a mechanism dependent on protein isoprenylation and palmitoylation that involves sorting of the protein into multivesicular bodies, mediated by the ESCRT machinery. Moreover, RhoB sorting is regulated by late endosome specific lipid dynamics and is altered in human genetic lipid traffic disease. CONCLUSIONS/SIGNIFICANCE Our findings characterize a short-lived cytosolic protein that is degraded through a lysosomal pathway. In addition, we define a novel motif for protein sorting and rapid degradation, which allows controlling protein levels by means of clinically used drugs.
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Affiliation(s)
- Dolores Pérez-Sala
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
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22
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Blanc C, Charette SJ, Mattei S, Aubry L, Smith EW, Cosson P, Letourneur F. DictyosteliumTom1 Participates to an Ancestral ESCRT-0 Complex. Traffic 2009; 10:161-71. [DOI: 10.1111/j.1600-0854.2008.00855.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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23
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Abstract
The two major cellular sites for membrane protein degradation are the proteasome and the lysosome. Ubiquitin attachment is a sorting signal for both degradation routes. For lysosomal degradation, ubiquitination triggers the sorting of cargo proteins into the lumen of late endosomal multivesicular bodies (MVBs)/endosomes. MVB formation occurs when a portion of the limiting membrane of an endosome invaginates and buds into its own lumen. Intralumenal vesicles are degraded when MVBs fuse to lysosomes. The proper delivery of proteins to the MVB interior relies on specific ubiquitination of cargo, recognition and sorting of ubiquitinated cargo to endosomal subdomains, and the formation and scission of cargo-filled intralumenal vesicles. Over the past five years, a number of proteins that may directly participate in these aspects of MVB function and biogenesis have been identified. However, major questions remain as to exactly what these proteins do at the molecular level and how they may accomplish these tasks.
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Affiliation(s)
- Robert C. Piper
- Department of Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242
| | - David J. Katzmann
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55095
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Charette SJ, Cosson P. A LYST/beige homolog is involved in biogenesis of Dictyostelium secretory lysosomes. J Cell Sci 2007; 120:2338-43. [PMID: 17606989 DOI: 10.1242/jcs.009001] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Chediak-Higashi syndrome (CHS) is characterized at the cellular level by a defect in the ability of cells to secrete lysosomes. However, the precise step affected in the secretion process is unclear. We characterized Dictyostelium discoideum cells containing a mutation in lvsB, the homolog of the human gene (LYST) involved in CHS. As observed in mammalian cells, secretion of lysosome-derived compartments was affected in lvsB mutant cells. This defect was mirrored by a decrease in the number of fusion-competent post-lysosomal compartments, which in Dictyostelium can be clearly distinguished from lysosomes. In addition, the transfer of endocytosed particles from lysosomes to post lysosomes was strongly diminished in lvsB mutant cells compared with the wild type. These results suggest that LvsB is primarily involved in transport from lysosomes to post lysosomes, and thus plays a critical role in the maturation of lysosomes into fusion-competent post-lysosomal compartments.
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Affiliation(s)
- Steve J Charette
- Université de Genève, Centre Médical Universitaire, Département de Physiologie Cellulaire et Métabolisme, 1 rue Michel Servet, CH-1211 Geneva 4, Switzerland.
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