title: Penetratin-Mediated Transepithelial Insulin Permeation: Importance of Cationic Residues and pH for Complexation and Permeation.
abstract: Penetratin is a widely used carrier peptide showing promising potential for mucosal delivery of therapeutic proteins. In the present study, the importance of specific penetratin residues and pH was investigated with respect to complexation with insulin and subsequent transepithelial insulin permeation. Besides penetratin, three analogues were studied. The carrier peptide-insulin complexes were characterized in terms of size and morphology at pH 5, 6.5, and 7.4 by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. At pH 7.4 mainly very large complexes were present, while much smaller complexes dominated at pH 5. Presence of arginine residues in the carrier peptide proved to be a prerequisite for complexation with insulin as well as for enhanced transepithelial insulin permeation in vitro. Rearrangement of tryptophan residues resulted in significantly increased insulin permeation as compared to that of the parent penetratin. In general, pre-complexation with penetratin and its analogues at pH 5 gave rise to increased insulin permeation as compared to that observed at pH 7.4; this finding was further supported by a preliminary in vivo study using the parent penetratin.
authors.affiliation: Section for Biologics, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark.
authors.forename: Mie
authors.initials: M
authors.lastname: Kristensen
authors.forename: Henrik
authors.initials: H
authors.lastname: Franzyk
authors.forename: Mia Thorne
authors.initials: MT
authors.lastname: Klausen
authors.forename: Anne
authors.initials: A
authors.lastname: Iversen
authors.forename: Jesper Søborg
authors.initials: JS
authors.lastname: Bahnsen
authors.forename: Rikke Bjerring
authors.initials: RB
authors.lastname: Skyggebjerg
authors.forename: Vito
authors.initials: V
authors.lastname: Foderà
authors.forename: Hanne Mørck
authors.initials: HM
authors.lastname: Nielsen
mesh_terms: D018938:Caco-2 Cells; D002352:Carrier Proteins / Q000737:chemistry*; D002412:Cations; D057846:Cell-Penetrating Peptides; D000067493:Dynamic Light Scattering; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission
chemical_list: D002352:Carrier Proteins; D002412:Cations; D057846:Cell-Penetrating Peptides; D007328:Insulin; C414409:penetratin