Brucella Egresses from Host Cells Exploiting Multivesicular Bodies

ABSTRACT Host cell egress is a critical step in the life cycle of intracellular pathogens, especially in microbes capable of establishing chronic infections. The Gram-negative bacterium Brucella belongs to such a group of pathogens. Even though much has been done to understand how Brucella avoids ki...

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Main Authors: Juan Manuel Spera, Francisco Guaimas, Cecilia Czibener, Juan Esteban Ugalde
Format: Article
Language:English
Published: American Society for Microbiology 2023-02-01
Series:mBio
Subjects:
Online Access:https://journals.asm.org/doi/10.1128/mbio.03338-22
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author Juan Manuel Spera
Francisco Guaimas
Cecilia Czibener
Juan Esteban Ugalde
author_facet Juan Manuel Spera
Francisco Guaimas
Cecilia Czibener
Juan Esteban Ugalde
author_sort Juan Manuel Spera
collection DOAJ
description ABSTRACT Host cell egress is a critical step in the life cycle of intracellular pathogens, especially in microbes capable of establishing chronic infections. The Gram-negative bacterium Brucella belongs to such a group of pathogens. Even though much has been done to understand how Brucella avoids killing and multiplies in its intracellular niche, the mechanism that this bacterium deploys to egress from the cell to complete its cycle has been poorly studied. In the manuscript, we quantify the kinetics of bacterial egress and show that Brucella exploits multivesicular bodies to exit host cells. For the first time, we visualized the process of egress in real time by live video microscopy and showed that a population of intracellular bacteria exit from host cells in vacuoles containing multivesicular body-like features. We observed the colocalization of Brucella with two multivesicular markers, namely, CD63 and LBPA, both during the final stages of the intracellular life cycle and in egressed bacteria. Moreover, drugs that either promote or inhibit multivesicular bodies either increased or decreased the number of extracellular bacteria, respectively. Our results strongly suggest that Brucella hijacks multivesicular bodies to exit the host cells to initiate new infection events. IMPORTANCE How intracellular bacterial pathogens egress from host cells has been poorly studied. This is particularly important because this stage of the infectious cycle can have a strong impact on how the host resolves the infection. Brucella is an intracellular pathogen that infects mammals, including humans, and causes a chronic debilitating illness. The bacterium has evolved a plethora of mechanisms to invade host cells, avoid degradation in the endocytic pathway, and actively multiply within a specialized intracellular compartment. However, how this pathogen exits from infected cells to produce reinfection and complete its life cycle is poorly understood. In the manuscript, we shed some light on the mechanisms that are exploited by Brucella to egress from host cells. We observed for the first time the egress of Brucella from infected cells by time-lapse video microscopy, and we found that the bacterium exits in vesicles containing multivesicular bodies (MVBs) features. Moreover, the drug manipulation of MVBs resulted in the alteration of bacterial egress efficiency. Our results indicate that Brucella hijacks MVBs to exit host cells and that this strongly contributes to the reinfection cycle.
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spelling doaj.art-dc810505acce4f34b614b7f1b9fc82752024-08-11T18:04:48ZengAmerican Society for MicrobiologymBio2150-75112023-02-0114110.1128/mbio.03338-22Brucella Egresses from Host Cells Exploiting Multivesicular BodiesJuan Manuel Spera0Francisco Guaimas1Cecilia Czibener2Juan Esteban Ugalde3Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, ArgentinaInstituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, ArgentinaInstituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, ArgentinaInstituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Buenos Aires, ArgentinaABSTRACT Host cell egress is a critical step in the life cycle of intracellular pathogens, especially in microbes capable of establishing chronic infections. The Gram-negative bacterium Brucella belongs to such a group of pathogens. Even though much has been done to understand how Brucella avoids killing and multiplies in its intracellular niche, the mechanism that this bacterium deploys to egress from the cell to complete its cycle has been poorly studied. In the manuscript, we quantify the kinetics of bacterial egress and show that Brucella exploits multivesicular bodies to exit host cells. For the first time, we visualized the process of egress in real time by live video microscopy and showed that a population of intracellular bacteria exit from host cells in vacuoles containing multivesicular body-like features. We observed the colocalization of Brucella with two multivesicular markers, namely, CD63 and LBPA, both during the final stages of the intracellular life cycle and in egressed bacteria. Moreover, drugs that either promote or inhibit multivesicular bodies either increased or decreased the number of extracellular bacteria, respectively. Our results strongly suggest that Brucella hijacks multivesicular bodies to exit the host cells to initiate new infection events. IMPORTANCE How intracellular bacterial pathogens egress from host cells has been poorly studied. This is particularly important because this stage of the infectious cycle can have a strong impact on how the host resolves the infection. Brucella is an intracellular pathogen that infects mammals, including humans, and causes a chronic debilitating illness. The bacterium has evolved a plethora of mechanisms to invade host cells, avoid degradation in the endocytic pathway, and actively multiply within a specialized intracellular compartment. However, how this pathogen exits from infected cells to produce reinfection and complete its life cycle is poorly understood. In the manuscript, we shed some light on the mechanisms that are exploited by Brucella to egress from host cells. We observed for the first time the egress of Brucella from infected cells by time-lapse video microscopy, and we found that the bacterium exits in vesicles containing multivesicular bodies (MVBs) features. Moreover, the drug manipulation of MVBs resulted in the alteration of bacterial egress efficiency. Our results indicate that Brucella hijacks MVBs to exit host cells and that this strongly contributes to the reinfection cycle.https://journals.asm.org/doi/10.1128/mbio.03338-22Brucellaegressmultivesicular bodies
spellingShingle Juan Manuel Spera
Francisco Guaimas
Cecilia Czibener
Juan Esteban Ugalde
Brucella Egresses from Host Cells Exploiting Multivesicular Bodies
mBio
Brucella
egress
multivesicular bodies
title Brucella Egresses from Host Cells Exploiting Multivesicular Bodies
title_full Brucella Egresses from Host Cells Exploiting Multivesicular Bodies
title_fullStr Brucella Egresses from Host Cells Exploiting Multivesicular Bodies
title_full_unstemmed Brucella Egresses from Host Cells Exploiting Multivesicular Bodies
title_short Brucella Egresses from Host Cells Exploiting Multivesicular Bodies
title_sort brucella egresses from host cells exploiting multivesicular bodies
topic Brucella
egress
multivesicular bodies
url https://journals.asm.org/doi/10.1128/mbio.03338-22
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AT franciscoguaimas brucellaegressesfromhostcellsexploitingmultivesicularbodies
AT ceciliaczibener brucellaegressesfromhostcellsexploitingmultivesicularbodies
AT juanestebanugalde brucellaegressesfromhostcellsexploitingmultivesicularbodies