Role of bacterial surface structures on the interaction of Klebsiella pneumoniae with phagocytes
Fecha
2013Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión publicada / Argitaratu den bertsioa
Impacto
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10.1371/journal.pone.0056847
Resumen
Phagocytosis is a key process of the immune system. The human pathogen Klebsiella pneumoniae is a well known example
of a pathogen highly resistant to phagocytosis. A wealth of evidence demonstrates that the capsule polysaccharide (CPS)
plays a crucial role in resistance to phagocytosis. The amoeba Dictyostelium discoideum shares with mammalian
macrophages the ability to phagocytose and kill b ...
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Phagocytosis is a key process of the immune system. The human pathogen Klebsiella pneumoniae is a well known example
of a pathogen highly resistant to phagocytosis. A wealth of evidence demonstrates that the capsule polysaccharide (CPS)
plays a crucial role in resistance to phagocytosis. The amoeba Dictyostelium discoideum shares with mammalian
macrophages the ability to phagocytose and kill bacteria. The fact that K. pneumoniae is ubiquitous in nature and, therefore,
should avoid predation by amoebae, poses the question whether K. pneumoniae employs similar means to counteract
amoebae and mammalian phagocytes. Here we developed an assay to evaluate K. pneumoniae-D. discoideum interaction.
The richness of the growth medium affected the threshold at which the cps mutant was permissive for Dictyostelium and
only at lower nutrient concentrations the cps mutant was susceptible to predation by amoebae. Given the critical role of
bacterial surface elements on host-pathogen interactions, we explored the possible contribution of the lipopolysaccharide
(LPS) and outer membrane proteins (OMPs) to combat phagoyctosis by D. discoideum. We uncover that, in addition to the
CPS, the LPS O-polysaccharide and the first core sugar participate in Klebsiella resistance to predation by D. discoideum. K.
pneumoniae LPS lipid A decorations are also necessary to avoid predation by amoebae although PagP-dependent
palmitoylation plays a more important role than the lipid A modification with aminoarabinose. Mutants lacking OMPs OmpA
or OmpK36 were also permissive for D. discoideium growth. Except the LPS O-polysaccharide mutants, all mutants were
more susceptible to phagocytosis by mouse alveolar macrophages. Finally, we found a correlation between virulence, using
the pneumonia mouse model, and resistance to phagocytosis. Altogether, this work reveals novel K. pneumoniae
determinants involved in resistance to phagocytosis and supports the notion that Dictyostelium amoebae might be useful as
host model to measure K. pneumoniae virulence and not only phagocytosis. [--]
Materias
Phagocytosis,
Klebsiella pneumoniae,
Dictyostelium discoideum,
Bacterial surface structures
Editor
Public Library of Science
Publicado en
Plos One, 8(2): e56847
Departamento
Universidad Pública de Navarra/Nafarroako Unibertsitate Publikoa. IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Versión del editor
Entidades Financiadoras
Part of this work was supported by Ministerio de Economía y Competitividad (Spain) and from Generalitat de Catalunya (Centre de Referencia en
Biotecnologia) grants to J.M.T.; by grants from Biomedicine Program (SAF2009-07885; Ministerio de Economía y Competitividad) and SEPAR (Sociedad Española
de Neumología, project reference 068/2011) to J.A.B. The laboratory of Microbial Pathogenesis is supported by a grant to Competitive groups (project reference
46/2011) from Govern Illes Balears (co-funded by European Regional Development Fund).