title: Selecting improved peptidyl motifs for cytosolic delivery of disparate protein and nanoparticle materials.
abstract: Cell penetrating peptides facilitate efficient intracellular uptake of diverse materials ranging from small contrast agents to larger proteins and nanoparticles. However, a significant impediment remains in the subsequent compartmentalization/endosomal sequestration of most of these cargoes. Previous functional screening suggested that a modular peptide originally designed to deliver palmitoyl-protein thioesterase inhibitors to neurons could mediate endosomal escape in cultured cells. Here, we detail properties relevant to this peptide's ability to mediate cytosolic delivery of quantum dots (QDs) to a wide range of cell-types, brain tissue culture and a developing chick embryo in a remarkably nontoxic manner. The peptide further facilitated efficient endosomal escape of large proteins, dendrimers and other nanoparticle materials. We undertook an iterative structure-activity relationship analysis of the peptide by discretely modifying key components including length, charge, fatty acid content and their order using a comparative, semiquantitative assay. This approach allowed us to define the key motifs required for endosomal escape, to select more efficient escape sequences, along with unexpectedly identifying a sequence modified by one methylene group that specifically targeted QDs to cellular membranes. We interpret our results within a model of peptide function and highlight implications for in vivo labeling and nanoparticle-mediated drug delivery by using different peptides to co-deliver cargoes to cells and engage in multifunctional labeling.
authors.affiliation: Center for Bio/Molecular Science and Engineering, Code 6900, US Naval Research Laboratory, Washington, DC 20375, United States.
authors.forename: Kelly
authors.initials: K
authors.lastname: Boeneman
authors.forename: James B
authors.initials: JB
authors.lastname: Delehanty
authors.forename: Juan B
authors.initials: JB
authors.lastname: Blanco-Canosa
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Susumu
authors.forename: Michael H
authors.initials: MH
authors.lastname: Stewart
authors.forename: Eunkeu
authors.initials: E
authors.lastname: Oh
authors.forename: Alan L
authors.initials: AL
authors.lastname: Huston
authors.forename: Glyn
authors.initials: G
authors.lastname: Dawson
authors.forename: Sampat
authors.initials: S
authors.lastname: Ingale
authors.forename: Ryan
authors.initials: R
authors.lastname: Walters
authors.forename: Miriam
authors.initials: M
authors.lastname: Domowicz
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Deschamps
authors.forename: W Russ
authors.initials: WR
authors.lastname: Algar
authors.forename: Stassi
authors.initials: S
authors.lastname: Dimaggio
authors.forename: Janet
authors.initials: J
authors.lastname: Manono
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Spillmann
authors.forename: Darren
authors.initials: D
authors.lastname: Thompson
authors.forename: Travis L
authors.initials: TL
authors.lastname: Jennings
authors.forename: Philip E
authors.initials: PE
authors.lastname: Dawson
authors.forename: Igor L
authors.initials: IL
authors.lastname: Medintz
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D057846:Cell-Penetrating Peptides / Q000737:chemistry* / Q000378:metabolism; D002642:Chick Embryo; D003600:Cytosol / Q000378:metabolism*; D004337:Drug Carriers / Q000737:chemistry* / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D006801:Humans; D058619:Maltose-Binding Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D045663:Quantum Dots
chemical_list: D057846:Cell-Penetrating Peptides; D004337:Drug Carriers; D058619:Maltose-Binding Proteins