Subversion of NPC1 pathway of cholesterol transport by Anaplasma phagocytophilum

Cell Microbiol. 2012 Apr;14(4):560-76. doi: 10.1111/j.1462-5822.2011.01742.x. Epub 2012 Feb 8.

Abstract

Intracellular cholesterol amounts, distribution and traffic are tightly regulated to maintain the healthy eukaryotic cell function. However, how intracellular pathogens that require cholesterol, interact with the host cholesterol homeostasis and traffic is not well understood. Anaplasma phagocytophilum is an obligatory intracellular and cholesterol-robbing bacterium, which causes human granulocytic anaplasmosis. Here we found that a subset of cholesterol-binding membrane protein, Niemann-Pick type C1 (NPC1)-bearing vesicles devoid of lysosomal markers were upregulated in HL-60 cells infected with A. phagocytophilum, and trafficked to live bacterial inclusions. The NPC1 localization to A. phagocytophilum inclusions was abolished by low-density lipoprotein (LDL)-derived cholesterol traffic inhibitor U18666A. Studies using NPC1 siRNA and the cell line with cholesterol traffic defect demonstrated that the NPC1 function is required for bacterial cholesterol acquisition and infection. Furthermore, trans-Golgi network-specific soluble N-ethylmaleimide-sensitive factor attachment protein receptors, vesicle-associated membrane protein (VAMP4) and syntaxin 16, which are associated with NPC1 and LDL-derived cholesterol vesicular transport were recruited to A. phagocytophilum inclusions, and VAMP4 was required for bacteria infection. Taken together, A. phagocytophilum is the first example of a pathogen that subverts the NPC1 pathway of intracellular cholesterol transport and homeostasis for bacterial inclusion membrane biogenesis and cholesterol capture.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Proteins, Vesicular Transport
  • Anaplasma phagocytophilum / drug effects
  • Anaplasma phagocytophilum / metabolism
  • Anaplasma phagocytophilum / pathogenicity*
  • Androstenes / pharmacology
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Membrane / metabolism
  • Cholesterol / metabolism*
  • Ehrlichiosis / metabolism*
  • Ehrlichiosis / microbiology
  • Gene Expression Regulation
  • Glycoproteins / genetics
  • Glycoproteins / metabolism
  • HL-60 Cells
  • Host-Pathogen Interactions
  • Humans
  • Inclusion Bodies / metabolism
  • Intracellular Signaling Peptides and Proteins
  • Lysosomal-Associated Membrane Protein 2
  • Lysosome-Associated Membrane Glycoproteins / genetics
  • Lysosome-Associated Membrane Glycoproteins / metabolism
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Niemann-Pick C1 Protein
  • Oxytetracycline / pharmacology
  • Protein Transport
  • R-SNARE Proteins / genetics
  • R-SNARE Proteins / metabolism
  • Syntaxin 16 / genetics
  • Syntaxin 16 / metabolism
  • Transport Vesicles / metabolism
  • Vesicular Transport Proteins

Substances

  • Adaptor Proteins, Vesicular Transport
  • Androstenes
  • Bacterial Proteins
  • Carrier Proteins
  • Glycoproteins
  • Intracellular Signaling Peptides and Proteins
  • LAMP2 protein, human
  • Lysosomal-Associated Membrane Protein 2
  • Lysosome-Associated Membrane Glycoproteins
  • Membrane Glycoproteins
  • Membrane Proteins
  • NPC1 protein, human
  • NPC2 protein, human
  • Niemann-Pick C1 Protein
  • R-SNARE Proteins
  • STARD3 protein, human
  • STARD5 protein, human
  • STX16 protein, human
  • Syntaxin 16
  • VAMP4 protein, human
  • Vesicular Transport Proteins
  • 3-beta-(2-(diethylamino)ethoxy)androst-5-en-17-one
  • Cholesterol
  • Oxytetracycline