title: Cell-penetrating peptide secures an efficient endosomal escape of an intact cargo upon a brief photo-induction.
abstract: Since their discovery, cell-penetrating peptides (CPPs) have provided a novel, efficient, and non-invasive mode of transport for various (bioactive) cargos into cells. Despite the ever-growing number of successful implications of the CPP-mediated delivery, issues concerning their intracellular trafficking, significant targeting to degradative organelles, and limited endosomal escape are still hindering their widespread use. To overcome these obstacles, we have utilized a potent photo-induction technique with a fluorescently labeled protein cargo attached to an efficient CPP, TP10. In this study we have determined some key requirements behind this induced escape (e.g., dependence on peptide-to-cargo ratio, time and cargo), and have semi-quantitatively assessed the characteristics of the endosomes that become leaky upon this treatment. Furthermore, we provide evidence that the photo-released cargo remains intact and functional. Altogether, we can conclude that the photo-induced endosomes are specific large complexes-condensed non-acidic vesicles, where the released cargo remains in its native intact form. The latter was confirmed with tubulin as the cargo, which upon photo-induction was incorporated into microtubules. Because of this, we propose that combining the CPP-mediated delivery with photo-activation technique could provide a simple method for overcoming major limitations faced today and serve as a basis for enhanced delivery efficiency and a subsequent elevated cellular response of different bioactive cargo molecules.
authors.affiliation: Institute of Molecular and Cell Biology, University of Tartu, 23 Riia Street, 51010, Tartu, Estonia, raagel@mpi-cbg.de.
authors.forename: Helin
authors.initials: H
authors.lastname: Räägel
authors.forename: Margot
authors.initials: M
authors.lastname: Hein
authors.forename: Asko
authors.initials: A
authors.lastname: Kriiska
authors.forename: Pille
authors.initials: P
authors.lastname: Säälik
authors.forename: Anders
authors.initials: A
authors.lastname: Florén
authors.forename: Ülo
authors.initials: Ü
authors.lastname: Langel
authors.forename: Margus
authors.initials: M
authors.lastname: Pooga
mesh_terms: D000818:Animals; D016466:CHO Cells; D057846:Cell-Penetrating Peptides / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D004337:Drug Carriers / Q000378:metabolism; D016503:Drug Delivery Systems; D011992:Endosomes / Q000378:metabolism*; D005456:Fluorescent Dyes; D019004:Galanin / Q000378:metabolism; D055668:Photochemical Processes; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014404:Tubulin / Q000008:administration & dosage / Q000378:metabolism; D014862:Wasp Venoms / Q000378:metabolism
chemical_list: D057846:Cell-Penetrating Peptides; D004337:Drug Carriers; D005456:Fluorescent Dyes; D011993:Recombinant Fusion Proteins; D014404:Tubulin; D014862:Wasp Venoms; C110068:transportan; D019004:Galanin