Cytosolic access of Mycobacterium tuberculosis: critical impact of phagosomal acidification control and demonstration of occurrence in vivo

Roxane Simeone; Fadel Sayes; Okryul Song; Matthias I Gröschel; Priscille Brodin; Roland Brosch; Laleh Majlessi

doi:10.1371/journal.ppat.1004650

Cytosolic access of Mycobacterium tuberculosis: critical impact of phagosomal acidification control and demonstration of occurrence in vivo

PLoS Pathog. 2015 Feb 6;11(2):e1004650. doi: 10.1371/journal.ppat.1004650. eCollection 2015 Feb.

Authors

Roxane Simeone¹, Fadel Sayes², Okryul Song³, Matthias I Gröschel², Priscille Brodin³, Roland Brosch², Laleh Majlessi²

Affiliations

¹ Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, Institut Pasteur, Paris, France; Inserm U1019, CNRS UMR8204, Université de Lille-Nord de France, Institut Pasteur de Lille, Center for Infection and Immunity, Lille, France.
² Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, Institut Pasteur, Paris, France.
³ Inserm U1019, CNRS UMR8204, Université de Lille-Nord de France, Institut Pasteur de Lille, Center for Infection and Immunity, Lille, France.

Abstract

Mycobacterium tuberculosis (Mtb) uses efficient strategies to evade the eradication by professional phagocytes, involving--as recently confirmed--escape from phagosomal confinement. While Mtb determinants, such as the ESX-1 type VII secretion system, that contribute to this phenomenon are known, the host cell factors governing this important biological process are yet unexplored. Using a newly developed flow-cytometric approach for Mtb, we show that macrophages expressing the phagosomal bivalent cation transporter Nramp-1, are much less susceptible to phagosomal rupture. Together with results from the use of the phagosome acidification inhibitor bafilomycin, we demonstrate that restriction of phagosomal acidification is a prerequisite for mycobacterial phagosomal rupture and cytosolic contact. Using different in vivo approaches including an enrichment and screen for tracking rare infected phagocytes carrying the CD45.1 hematopoietic allelic marker, we here provide first and unique evidence of M. tuberculosis-mediated phagosomal rupture in mouse spleen and lungs and in numerous phagocyte types. Our results, linking the ability of restriction of phagosome acidification to cytosolic access, provide an important conceptual advance for our knowledge on host processes targeted by Mtb evasion strategies.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Bacterial Secretion Systems / immunology*
Cation Transport Proteins / genetics
Cation Transport Proteins / immunology*
Cell Line, Tumor
Humans
Hydrogen-Ion Concentration
Leukocyte Common Antigens / genetics
Leukocyte Common Antigens / immunology
Macrophages / immunology*
Macrophages / microbiology
Mice
Mice, Mutant Strains
Mycobacterium tuberculosis / immunology*
Phagosomes / genetics
Phagosomes / immunology*
Tuberculosis / genetics
Tuberculosis / immunology*
Tuberculosis / pathology

Substances

Bacterial Secretion Systems
Cation Transport Proteins
natural resistance-associated macrophage protein 1
Leukocyte Common Antigens
PTPRC protein, human
Ptprc protein, mouse

Grants and funding

This work was supported by the European Community’s Framework Programme 7 grants NEWTBVAC 241745, MM4TB 260872 and INTRACELLTB 260901, the Institut Pasteur (PTR441), the Agence Nationale de Recherche, the Feder (12001407 (D-AL) Equipex Imaginex BioMed), the Region Nord Pas de Calais and the Fondation pour la Recherche Médicale FRM n^oDEQ20130326471 (to RB). MIG is a recipient of a Jan Kornelis de Cock Stichting scholarship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.