Yersinia pseudotuberculosis induces transcytosis of nanoparticles across human intestinal villus epithelium via invasin-dependent macropinocytosis

Abstract

Crohn's disease is characterized by a defect in intestinal barrier function, where bacteria are considered the most important inflammation-driving factor. Enteric bacteria, including E. coli and Yersinia spp, affect tight junctions in enterocytes, but little is known about bacterial effects on the transcellular pathway. Our objective was to study the short-term effects of Y. pseudotuberculosis on uptake of nanoparticles across human villus epithelium. Monolayers of human colon epitheliumderived Caco-2 cells and biopsies of normal human ileum were studied after 2 h exposure to Y. pseudotuberculosis expressing (inv þ ) or lacking (invÀ) the bacterial adhesion molecule, invasin. Transepithelial transport of fluorescent nanoparticles (markers of transcytosis) was quantified by flow cytometry, and mechanisms explored by using inhibitors of endocytosis. Epithelial expressions of b1-integrin and particle uptake pathways were studied by confocal microscopy. The paracellular pathway was assessed by electrical resistance (TER), mannitol flux, and expression of tight junction proteins occludin and caludin-4 by confocal microscopy. Inv þ Y. pseudotuberculosis adhered to the apical surface of epithelial cells and induced transcytosis of exogenous nanoparticles across Caco-2 monolayers (30-fold increase, Po0.01) and ileal mucosa (268 ± 47% of control; Po0.01), whereas invÀ bacteria had no effect on transcytosis. The transcytosis was concentration-, particle size-and temperature-dependent, and possibly mediated via macropinocytosis. Y. pseudotuberculosis also induced apical expression of b1-integrin on epithelial cells. A slight drop in TER was seen after exposure to inv þ Y. pseudotuberculosis, whereas mannitol flux and tight junction protein expression was unchanged. In summary, Y. pseudotuberculosis induced apical expression of b1-integrin and stimulated uptake of nanoparticles via invasindependent transcytosis in human intestinal epithelium. Our findings suggest that bacterial factors may initiate transcytosis of luminal exogenous particles across human ileal mucosa, thus presenting a novel mechanism of intestinal barrier dysfunction.

Yersinia pseudotuberculosis disrupts intestinal barrier integrity through hematopoietic TLR-2 signaling

“…Our data support the key role of TLR-2 after Y. pseudotuberculosis infection by demonstrating its role in intestinal barrier dysfunction. This finding is consistent with recent reports showing that TLR-2 activation is involved in transepithelial transport of microparticles (16,32) and transcellular permeability through PPs (42). However, the effect of TLR-2 activation on gut permeability is still subject to debate, and some studies argue for a protective role of TLR-2 on intestinal permeability.…”

“…Previously reported in vitro data have shown that Y. pseudotuberculosis affects gut permeability via paracellular and transcellular routes (26,32). In addition, an increase of paracellular permeability is observed in patients with a history of Y. pseudotuberculosis infection compared with healthy controls (24,25).…”

The M Cell-Targeting Ligand Promotes Antigen Delivery and Induces Antigen-Specific Immune Responses in Mucosal Vaccination

“…Consequently, we investigated the possible involvement of Co1 in signal transduction rather than just binding through searching for homologous proteins in protein databases. The outer membrane protein H (OmpH) of Yersinia enterocolitica, an M cell pathogen recently used as an oral carrier, showed the highest sequence homology to Co1 (61)(62)(63)(64). OmpH of Yersinia, also known as the Skp chaperone protein or cationic 19 kDa outer membrane protein, belongs to the HlpA superfamily of proteins.…”

Mechanistic studies on the uptake and intracellular trafficking of novel cyclodextrin transfection complexes by intestinal epithelial cells

“…The endocytotic mechanism(s) by which GDV complexes enter cells depends on both the cell type and the physiochemical characteristics of the complexes. Using models of enterocytes (such as Caco-2 cells) and other polarised epithelia (such as MDCK cells), a number of endocytotic processes have been implicated as uptake pathways for delivery systems and nanoparticles in enterocytes (Kitchens et al 2007) (Ma and Lim 2003) (Ragnarsson et al 2008) (Roger et al 2009) (Gao et al 2008).…”