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Hétérogénéité phénotypique de Legionella pneumophila lors d'infection de cellules phagocytaires

English title Phenotypic Heterogeneity of Legionella pneumophila in Phagocytes
Applicant Personnic Nicolas
Number 161492
Funding scheme Ambizione
Research institution Institut für Medizinische Mikrobiologie Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Experimental Microbiology
Start/End 01.01.2016 - 31.12.2018
Approved amount 581'490.00
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All Disciplines (2)

Discipline
Experimental Microbiology
Cellular Biology, Cytology

Keywords (10)

Heterogeneity; Legionella; Phagocyte; Infection; Trafficking; Proteome; Vacuole; Virulence; Metabolism; Membrane

Lay Summary (French)

Lead
Les travaux concernant Legionella pneumophila porte sur le comportement global de la population bactérienne étudiée plutôt que sur les individus qui la composent. Notre projet vise l’identification de comportements individuels distincts dans une population isogénique de Legionella pneumophila lors de l’infection de cellules phagocytaires et la caractérisation des causes et conséquences de l'hétérogénéité phénotypique dans le processus infectieux.
Lay summary

Legionella pneumophila  est une bactérie de l’environnement résidant dans  les milieux humides et les eaux douces aussi bien que dans les réseaux d’eau potable. C’est un agent pathogène humain opportuniste à l’origine d’une très grave pneumonie, la maladie du Légionnaire, dont le taux de mortalité peut atteindre 20%. La capacité de Legionella pneumophila à survivre dans des environnements très différents repose notamment sur sa remarquable faculté à se répliquer dans les cellules phagocytaires et normalement bactéricides telle que les amibes ou les macrophages alvéolaires du poumon. Une fois phagocytée, Legionella pneumophila établit une niche propice à sa réplication en piratant les fonctions cellulaires de la cellule infectée par la sécrétion de centaines « d’effecteurs » protéiques.

Les travaux concernant Legionella pneumophila ont toujours porté sur le comportement global de la population bactérienne étudiée plutôt que sur les individus qui la composent. Ils ignorent de fait qu’une population bactérienne isogénique (génétiquement identique) est probablement constituée d’individus phénotypiquement hétérogènes en raison, entre autre, de la stochasticité des processus cellulaires et des fluctuations environnementales dont la complexité augmente dans le contexte infectieux.

Notre projet vise dans un premier temps l’identification de comportements individuels distincts dans une population isogénique de  Legionella pneumophila lors de l’infection de cellules phagocytaires. Dans une seconde phase, nous rechercherons les causes régissant ces variations et les conséquences en termes de résistance, de prolifération ou encore de capacité d’adaptation.

Cette étude permettra une meilleure compréhension de l’interaction complexe entre une bactérie pathogène et son hôte et devrait contribuer à l’indentification de nouvelles pistes pour de futurs traitements.

Direct link to Lay Summary Last update: 01.09.2015

Responsible applicant and co-applicants

Employees

Publications

Publication
Single Cell Analysis of Legionella and Legionella-Infected Acanthamoeba by Agarose Embedment
Personnic Nicolas, Striednig Bianca, Hilbi Hubert (2018), Single Cell Analysis of Legionella and Legionella-Infected Acanthamoeba by Agarose Embedment, Humana Press, Totowa, NJ.
Legionella quorum sensing and its role in pathogen-host interactions.
Striednig Bianca, Personnic Nicolas, Hilbi Hubert (2017), Legionella quorum sensing and its role in pathogen-host interactions., in Current opinion in microbiology, 41, 29-35.
ER remodeling by the large GTPase atlastin promotes vacuolar growth of Legionella pneumophila.
Steiner Bernhard, Welin Amanda, Personnic Nicolas, Freyre Christophe, Klemm Robin W, Hilbi Hubert, Swart Anna Leoni, Weber Stephen, Kaech Andres, Ziegler Urs (2017), ER remodeling by the large GTPase atlastin promotes vacuolar growth of Legionella pneumophila., in EMBO reports, 18(10), 1817-1836.
Subversion of Retrograde Trafficking by Translocated Pathogen Effectors.
Personnic Nicolas, Bärlocher Kevin, Finsel Ivo, Hilbi Hubert (2016), Subversion of Retrograde Trafficking by Translocated Pathogen Effectors., in Trends in microbiology, 24(6), 450-62.
PIKfyve/Fab1 is required for efficient V-ATPase and hydrolase delivery to phagosomes, phagosomal killing, and restriction of Legionella infection
BuckleyCatherine M, HeathVictoria L, GuehoAurelie, BosmaniCristina, KnoblochPaulina, SikakanaPhumzile, PersonnicNicolas, DoveStephen K, MichellRobert H, MeierRoger, HilbiHubert, SoldatiThierry, InsallRobert H, KingJason, PIKfyve/Fab1 is required for efficient V-ATPase and hydrolase delivery to phagosomes, phagosomal killing, and restriction of Legionella infection, in PLOS Pathogens, proof.

Collaboration

Group / person Country
Types of collaboration
Biozentrum Basel - Proteomics core facility Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Université Clermont-Auvergne France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
UZH - Center for Microscopy and Image Analysis Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Seminar Translational Medecine: Infection & Immunity Individual talk Bacterial phenotypic heterogeneity and Infection 05.12.2018 University Hospital Zurich, Switzerland Personnic Nicolas;
2018 Institut Pasteur International Network Symposium: Combating resistance: microbes and vectors Talk given at a conference The L. pneumophila quorum sensing system promotes persister formation in infected A. castellanii 15.11.2018 Insitut Pasteur, France Personnic Nicolas;
Invited talk Individual talk Legionella persistence and community behavior in its amoebal host Acanthamoeba castellanii 01.10.2018 University of Geneva, Switzerland Personnic Nicolas;
HEARD2018: Halting antimicrobial resistance and dissemination in aquatic environment Poster The L. pneumophila quorum sensing system promotes persister formation in infected A. castellanii 18.09.2018 Locarno, Monte Verita, Switzerland Personnic Nicolas;
EMBO workshop: bacterial persistence and antimicrobial therapy Poster The L. pneumophila quorum sensing system promotes persister formation in infected A. castellanii 10.06.2018 Locarno, Monte verita, Switzerland Personnic Nicolas;
Seminar Translational Medicine: Infection & Immunity Individual talk Bacterial phenotypic heterogeneity and Infection 08.11.2017 University Hospital Zurich, Switzerland Personnic Nicolas;
Bacterial individuality and infection Individual talk Bacterial individuality and infection 13.01.2017 Université Clermont-Auvergne, France Personnic Nicolas;
Seminar Translational Medicine: Infection & Immunity Individual talk Bacterial phenotypic heterogeneity and infection 19.10.2016 University Hospital Zurich, Switzerland Personnic Nicolas;


Associated projects

Number Title Start Funding scheme
185529 Hétérogénéité phénotypique de Legionella pneumophila 01.01.2019 Ambizione

Abstract

An emerging concept holds that genetically identical bacteria show surprisingly high levels of variation in phenotypic traits. Phenotypic noise and stochastic cellular processes are sources of heterogeneity. Furthermore, phenotypic variations also reflect bacterial responses to distinct environments. Recent studies revealed that host tissue micro-environments and the milieu of single host cells trigger phenotypic variation of intracellular bacterial pathogens. However, the molecular bases underlying phenotypic variability are largely unknown.Legionella pneumophila is the causative agent of a severe pneumonia termed “Legionnaires’ disease”. The bacteria replicate within free-living amoebae and lung alveolar macrophages in a distinct membrane-bound compartment, the “Legionella-containing vacuole” (LCV). Formation of this replicative niche involves the bacterial Icm/Dot type IV secretion system (T4SS) and approximately 300 different secreted “effector” proteins. LCVs avoid the fusion with bactericidal lysosomes, but communicate with the endosomal, secretory and retrograde vesicle trafficking pathways, and eventually fuse with the endoplasmic reticulum (ER). One may suggest that LCVs subversion of host cell membrane trafficking is required to support bacterial growth by providing required membranes, nutrients and host cell factors.L. pneumophila employs a biphasic life style to switch between intracellular replication and transmission to new hosts. In vitro, exponentially growing bacteria repress transmissive traits and induce these features upon entering the stationary phase. The transition is reversible and triggered by nutrient limitation and/or the bacterial density. Recent preliminary experiments using a fluorescent reporter revealed the emergence of heterogeneous subpopulations of L. pneumophila in infected phagocytes.In this application, I propose to characterize in detail the phenotypic heterogeneity of intracellular L. pneumophila in Dictyostelium discoideum amoebae and mammalian macrophages. To this end, heterogeneity in the growth rate, metabolism, virulence and motility of the bacteria will be assessed at a single cell level in dependence of the bacterial and host cell genotype and in response to the small bacterial signaling molecule LAI-1, nutrients and antibiotics.
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