Prion uptake in the gut: identification of the first uptake and replication sites

PLoS Pathog. 2011 Dec;7(12):e1002449. doi: 10.1371/journal.ppat.1002449. Epub 2011 Dec 22.

Abstract

After oral exposure, prions are thought to enter Peyer's patches via M cells and accumulate first upon follicular dendritic cells (FDCs) before spreading to the nervous system. How prions are actually initially acquired from the gut lumen is not known. Using high-resolution immunofluorescence and cryo-immunogold electron microscopy, we report the trafficking of the prion protein (PrP) toward Peyer's patches of wild-type and PrP-deficient mice. PrP was transiently detectable at 1 day post feeding (dpf) within large multivesicular LAMP1-positive endosomes of enterocytes in the follicle-associated epithelium (FAE) and at much lower levels within M cells. Subsequently, PrP was detected on vesicles in the late endosomal compartments of macrophages in the subepithelial dome. At 7-21 dpf, increased PrP labelling was observed on the plasma membranes of FDCs in germinal centres of Peyer's patches from wild-type mice only, identifying FDCs as the first sites of PrP conversion and replication. Detection of PrP on extracellular vesicles displaying FAE enterocyte-derived A33 protein implied transport towards FDCs in association with FAE-derived vesicles. By 21 dpf, PrP was observed on the plasma membranes of neurons within neighbouring myenteric plexi. Together, these data identify a novel potential M cell-independent mechanism for prion transport, mediated by FAE enterocytes, which acts to initiate conversion and replication upon FDCs and subsequent infection of enteric nerves.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Membrane / metabolism
  • Cell Membrane / ultrastructure
  • Dendritic Cells, Follicular / metabolism
  • Dendritic Cells, Follicular / ultrastructure
  • Endosomes / metabolism
  • Endosomes / ultrastructure
  • Enteric Nervous System / metabolism*
  • Enteric Nervous System / ultrastructure
  • Enterocytes / metabolism*
  • Enterocytes / ultrastructure
  • Lysosomal Membrane Proteins / genetics
  • Lysosomal Membrane Proteins / metabolism
  • Lysosomal-Associated Membrane Protein 1
  • Macrophages / metabolism
  • Macrophages / ultrastructure
  • Mice
  • Mice, Knockout
  • Peyer's Patches / metabolism*
  • Peyer's Patches / ultrastructure
  • Prion Diseases / genetics
  • Prion Diseases / metabolism
  • Prion Diseases / pathology
  • Prion Diseases / transmission*
  • Prions / genetics
  • Prions / metabolism*
  • Prions / pathogenicity*
  • Protein Transport
  • Time Factors

Substances

  • Lysosomal Membrane Proteins
  • Prions
  • Lamp1 protein, mouse
  • Lysosomal-Associated Membrane Protein 1