von Bargen, Kristine, Scraba, Mirella, Kraemer, Ina, Ketterer, Maren, Nehls, Christian, Krokowski, Sina, Repnik, Urska, Wittlich, Michaela, Maaser, Anna, Zapka, Pia, Bunge, Madeleine, Schlesinger, Martin, Huth, Gitta, Klees, Annette, Hansen, Philipp, Jeschke, Andreas, Bendas, Gerd, Utermoehlen, Olaf, Griffiths, Gareth, Gutsmann, Thomas, Wohlmann, Jens and Haas, Albert (2019). Virulence-associated protein A from Rhodococcus equi is an intercompartmental pH-neutralising virulence factor. Cell Microbiol., 21 (1). HOBOKEN: WILEY. ISSN 1462-5822

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Abstract

Professional phagocytic cells such as macrophages are a central part of innate immune defence. They ingest microorganisms into membrane-bound compartments (phagosomes), which acidify and eventually fuse with lysosomes, exposing their contents to a microbicidal environment. Gram-positive Rhodococcus equi can cause pneumonia in young foals and in immunocompromised humans. The possession of a virulence plasmid allows them to subvert host defence mechanisms and to multiply in macrophages. Here, we show that the plasmid-encoded and secreted virulence-associated protein A (VapA) participates in exclusion of the proton-pumping vacuolar-ATPase complex from phagosomes and causes membrane permeabilisation, thus contributing to a pH-neutral phagosome lumen. Using fluorescence and electron microscopy, we show that VapA is also transferred from phagosomes to lysosomes where it permeabilises the limiting membranes for small ions such as protons. This permeabilisation process is different from that of known membrane pore formers as revealed by experiments with artificial lipid bilayers. We demonstrate that, at 24 hr of infection, virulent R. equi is contained in a vacuole, which is enriched in lysosome material, yet possesses a pH of 7.2 whereas phagosomes containing a vapA deletion mutant have a pH of 5.8 and those with virulence plasmid-less sister strains have a pH of 5.2. Experimentally neutralising the macrophage endocytic system allows avirulent R. equi to multiply. This observation is mirrored in the fact that virulent and avirulent R. equi multiply well in extracts of purified lysosomes at pH 7.2 but not at pH 5.1. Together these data indicate that the major function of VapA is to generate a pH-neutral and hence growth-promoting intracellular niche. VapA represents a new type of Gram-positive virulence factor by trafficking from one subcellular compartment to another, affecting membrane permeability, excluding proton-pumping ATPase, and consequently disarming host defences.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
von Bargen, KristineUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Scraba, MirellaUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Kraemer, InaUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Ketterer, MarenUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Nehls, ChristianUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Krokowski, SinaUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Repnik, UrskaUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wittlich, MichaelaUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Maaser, AnnaUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Zapka, PiaUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Bunge, MadeleineUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Schlesinger, MartinUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Huth, GittaUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Klees, AnnetteUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Hansen, PhilippUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Jeschke, AndreasUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Bendas, GerdUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Utermoehlen, OlafUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Griffiths, GarethUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Gutsmann, ThomasUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wohlmann, JensUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Haas, AlbertUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-140719
DOI: 10.1111/cmi.12958
Journal or Publication Title: Cell Microbiol.
Volume: 21
Number: 1
Date: 2019
Publisher: WILEY
Place of Publication: HOBOKEN
ISSN: 1462-5822
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
MYCOBACTERIUM-TUBERCULOSIS; VACUOLAR ATPASE; SURVIVAL; PLASMID; MODEL; ACIDIFICATION; LYSOSOMES; MEMBRANES; FUSION; LIPIDSMultiple languages
Cell Biology; MicrobiologyMultiple languages
Refereed: Yes
URI: http://kups.ub.uni-koeln.de/id/eprint/14071

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