title: Mode of action of claudin peptidomimetics in the transient opening of cellular tight junction barriers.
abstract: In epithelial/endothelial barriers, claudins form tight junctions, seal the paracellular cleft, and limit the uptake of solutes and drugs. The peptidomimetic C1C2 from the C-terminal half of claudin-1's first extracellular loop increases drug delivery through epithelial claudin-1 barriers. However, its molecular and structural mode of action remains unknown. In the present study, >100 μM C1C2 caused paracellular opening of various barriers with different claudin compositions, ranging from epithelial to endothelial cells, preferentially modulating claudin-1 and claudin-5. After 6 h incubation, C1C2 reversibly increased the permeability to molecules of different sizes; this was accompanied by redistribution of claudins and occludin from junctions to cytosol. Internalization of C1C2 in epithelial cells depended on claudin-1 expression and clathrin pathway, whereby most C1C2 was retained in recyclosomes >2 h. In freeze-fracture electron microscopy, C1C2 changed claudin-1 tight junction strands to a more parallel arrangement and claudin-5 strands from E-face to P-face association - drastic and novel effects. In conclusion, C1C2 is largely recycled in the presence of a claudin, which explains the delayed onset of barrier and junction loss, the high peptide concentration required and the long-lasting effect. Epithelial/endothelial barriers are specifically modulated via claudin-1/claudin-5, which can be targeted to improve drug delivery.
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie, Berlin-Buch 13125, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Staat
authors.affiliation: Theodor Kocher Institute, University of Bern, Bern 3012, Switzerland.
authors.forename: Caroline
authors.initials: C
authors.lastname: Coisne
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie, Berlin-Buch 13125, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Dabrowski
authors.affiliation: University of Michigan, Medical School, Ann Arbor 48109-5602, USA.
authors.forename: Svetlana M
authors.initials: SM
authors.lastname: Stamatovic
authors.affiliation: University of Michigan, Medical School, Ann Arbor 48109-5602, USA.
authors.forename: Anuska V
authors.initials: AV
authors.lastname: Andjelkovic
authors.affiliation: Institute of Pathology and Neuropathology, University of Tuebingen, Tuebingen 72076, Germany.
authors.forename: Hartwig
authors.initials: H
authors.lastname: Wolburg
authors.affiliation: Theodor Kocher Institute, University of Bern, Bern 3012, Switzerland.
authors.forename: Britta
authors.initials: B
authors.lastname: Engelhardt
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie, Berlin-Buch 13125, Germany. Electronic address: iblasig@fmp-berlin.de.
authors.forename: Ingolf E
authors.initials: IE
authors.lastname: Blasig
mesh_terms: D018938:Caco-2 Cells; D002463:Cell Membrane Permeability / Q000502:physiology*; D042783:Endothelial Cells / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D057786:Peptidomimetics / Q000378:metabolism*; D062725:Tight Junction Proteins / Q000378:metabolism*; D019108:Tight Junctions / Q000378:metabolism*
chemical_list: D057786:Peptidomimetics; D062725:Tight Junction Proteins
keywords: Brain endothelial cells; Controlled drug release; Endocytosis; Freeze-fracture electron microscopy; Peptidomimetics; Tight junction proteins