title: Gb3-binding lectins as potential carriers for transcellular drug delivery.
abstract: OBJECTIVE
  Epithelial cell layers as well as endothelia forming the blood-brain barrier can drastically reduce the efficiency of drug targeting. Our goal was to investigate lectins recognizing the glycosphingolipid globotriaosylceramide (Gb3) for their potential as carriers for transcytotic drug delivery.
  
  
  METHODS
  We utilized an in vitro model based on Madin-Darby canine kidney cells transfected with Gb3 synthase to characterize transcytosis of the Gb3-binding lectins LecA from Pseudomonas aeruginosa and the B-subunit of Shiga toxin (StxB).
  
  
  RESULTS
  Both lectins were rapidly transcytosed from the apical to the basolateral plasma membrane and vice versa. Whereas StxB proceeded on retrograde and transcytotic routes, LecA avoided retrograde transport. This differential trafficking could be explained by our observation that LecA and StxB segregated into different domains during endocytosis. Furthermore, inhibiting the small GTPase Rab11a, which organizes trafficking through apical recycling endosomes, blocked basolateral to apical transcytosis of both lectins.
  
  
  CONCLUSIONS
  Gb3-binding lectins are promising candidates for transcytotic drug delivery. Our findings highlight that LecA and StxB, which both bind Gb3 but exhibit dissimilar valence and molecular structures of their carbohydrate binding sites and can take divergent intracellular trafficking routes. This opens up the possibility of developing tailor-made glycosphingolipid-binding carrier lectins, which take optimized trafficking pathways.
authors.affiliation: a Faculty of Biology , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|b BIOSS - Centre for Biological Signalling Studies , Albert-Ludwigs-University Freiburg , Freiburg , Germany.
authors.forename: Stefan K
authors.initials: SK
authors.lastname: Müller
authors.affiliation: a Faculty of Biology , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|b BIOSS - Centre for Biological Signalling Studies , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|c Spemann Graduate School of Biology and Medicine , Albert-Ludwigs University of Freiburg , Freiburg , Germany.
authors.forename: Isabel
authors.initials: I
authors.lastname: Wilhelm
authors.affiliation: a Faculty of Biology , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|b BIOSS - Centre for Biological Signalling Studies , Albert-Ludwigs-University Freiburg , Freiburg , Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schubert
authors.affiliation: a Faculty of Biology , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|b BIOSS - Centre for Biological Signalling Studies , Albert-Ludwigs-University Freiburg , Freiburg , Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Zittlau
authors.affiliation: d Centre de Recherches sur les Macromolécules Végétales, UPR5301 , CNRS and Université Grenoble Alpes , Grenoble , France.
authors.forename: Anne
authors.initials: A
authors.lastname: Imberty
authors.affiliation: a Faculty of Biology , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|b BIOSS - Centre for Biological Signalling Studies , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|c Spemann Graduate School of Biology and Medicine , Albert-Ludwigs University of Freiburg , Freiburg , Germany.
authors.forename: Josef
authors.initials: J
authors.lastname: Madl
authors.affiliation: a Faculty of Biology , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|b BIOSS - Centre for Biological Signalling Studies , Albert-Ludwigs-University Freiburg , Freiburg , Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Eierhoff
authors.affiliation: a Faculty of Biology , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|b BIOSS - Centre for Biological Signalling Studies , Albert-Ludwigs-University Freiburg , Freiburg , Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Thuenauer
authors.affiliation: a Faculty of Biology , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|b BIOSS - Centre for Biological Signalling Studies , Albert-Ludwigs-University Freiburg , Freiburg , Germany.|c Spemann Graduate School of Biology and Medicine , Albert-Ludwigs University of Freiburg , Freiburg , Germany.
authors.forename: Winfried
authors.initials: W
authors.lastname: Römer
mesh_terms: D000818:Animals; D001692:Biological Transport; D001812:Blood-Brain Barrier / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004285:Dogs; D016503:Drug Delivery Systems; D004705:Endocytosis; D004847:Epithelial Cells / Q000378:metabolism*; D037102:Lectins / Q000378:metabolism*; D061985:Madin Darby Canine Kidney Cells; D021381:Protein Transport; D014281:Trihexosylceramides / Q000378:metabolism*
chemical_list: D037102:Lectins; D014281:Trihexosylceramides; C018549:globotriaosylceramide
keywords: Apical recycling endosome; LecA; MDCK cells; Rab11; Shiga toxin; transcytosis