Trehalose dimycolate interferes with FcγR-mediated phagosome maturation through Mincle, SHP-1 and FcγRIIB signalling

PLoS One. 2017 Apr 6;12(4):e0174973. doi: 10.1371/journal.pone.0174973. eCollection 2017.

Abstract

The causative agent of tuberculosis, Mycobacterium tuberculosis (M. tuberculosis), contains an abundant cell wall glycolipid and a crucial virulence factor, trehalose-6,6'-dimycolate (TDM). TDM causes delay of phagosome maturation and thus promotes survival of mycobacteria inside host macrophages by a not fully understood mechanism. TDM signals through the Monocyte-INducible C-type LEctin (Mincle), a recently identified pattern recognition receptor. Here we show that recruitment of Mincle by TDM coupled to immunoglobulin (Ig)G-opsonised beads during Fcγ receptor (FcγR)-mediated phagocytosis interferes with phagosome maturation. In addition, modulation of phagosome maturation by TDM requires SH2-domain-containing inositol polyphosphate 5' phosphatase (SHP-1) and the FcγRIIB, which strongly suggests inhibitory downstream signalling of Mincle during phagosome formation. Overall, our study reveals important mechanisms contributing to the virulence of TDM.

MeSH terms

  • Animals
  • Cell Line
  • Lectins, C-Type / metabolism*
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Phagosomes / drug effects*
  • Phagosomes / metabolism
  • Protein Tyrosine Phosphatase, Non-Receptor Type 6 / metabolism*
  • Receptors, IgG / metabolism*
  • Signal Transduction*
  • Trehalose / pharmacology*

Substances

  • Clecsf8 protein, mouse
  • Fcgr2b protein, mouse
  • Lectins, C-Type
  • Membrane Proteins
  • Receptors, IgG
  • Trehalose
  • Protein Tyrosine Phosphatase, Non-Receptor Type 6
  • Ptpn6 protein, mouse