title: Cellular uptake and membrane-destabilising properties of alpha-peptide/beta-peptoid chimeras: lessons for the design of new cell-penetrating peptides.
abstract: Novel peptidomimetic backbone designs with stability towards proteases are of interest for several pharmaceutical applications including intracellular delivery. The present study concerns the cellular uptake and membrane-destabilising effects of various cationic chimeras comprised of alternating N-alkylated beta-alanine and alpha-amino acid residues. For comparison, homomeric peptides displaying octacationic functionalities as well as the Tat(47-57) sequence were included as reference compounds. Cellular uptake studies with fluorescently labelled compounds showed that guanidinylated chimeras were taken up four times more efficiently than Tat(47-57). After internalisation, the chimeras were localised primarily in vesicular compartments and diffusively in the cytoplasm. In murine NIH3T3 fibroblasts, the chimeras showed immediate plasma membrane permeabilising properties, which proved highly dependent on the chimera chain length, and were remarkably different from the effects induced by Tat(47-57). Finally, biophysical studies on model membranes showed that the chimeras in general increase the permeability of fluid phase and gel phase phosphatidylcholine (PC) vesicles without affecting membrane acyl chain packing, which suggests that they restrict lateral diffusion of the membrane lipids by interaction with phospholipid head groups. The alpha-peptide/beta-peptoid chimeras described herein exhibit promising cellular uptake properties, and thus represent proteolytically stable alternatives to currently known cell-penetrating peptides.
authors.affiliation: Department of Pharmaceutics and Analytical Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark. cfo@farma.ku.dk
authors.forename: Camilla
authors.initials: C
authors.lastname: Foged
authors.forename: Henrik
authors.initials: H
authors.lastname: Franzyk
authors.forename: Shervin
authors.initials: S
authors.lastname: Bahrami
authors.forename: Sven
authors.initials: S
authors.lastname: Frokjaer
authors.forename: Jerzy W
authors.initials: JW
authors.lastname: Jaroszewski
authors.forename: Hanne M
authors.initials: HM
authors.lastname: Nielsen
authors.forename: Christian A
authors.initials: CA
authors.lastname: Olsen
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects; D022162:Cytoplasmic Vesicles / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D005452:Fluoresceins / Q000378:metabolism; D015696:Gene Products, tat / Q000737:chemistry / Q000494:pharmacology; D019791:Guanidine / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D008567:Membranes, Artificial; D051379:Mice; D018613:Microscopy, Confocal; D041681:NIH 3T3 Cells; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology*; D034444:Peptoids / Q000737:chemistry* / Q000494:pharmacology*; D044367:Phase Transition / Q000187:drug effects; D010713:Phosphatidylcholines / Q000378:metabolism; D010715:Phosphatidylglycerols / Q000378:metabolism; D013696:Temperature
chemical_list: D005452:Fluoresceins; D015696:Gene Products, tat; D008567:Membranes, Artificial; D010455:Peptides; D034444:Peptoids; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; D019791:Guanidine; C028694:1-palmitoyl-2-oleoylphosphatidylcholine; C007740:fluorexon; C030345:1,2-dipalmitoylphosphatidylglycerol