title: Combined treatment with a pH-sensitive fusogenic peptide and cationic lipids achieves enhanced cytosolic delivery of exosomes.
abstract: Exosomes, which are approximately 100 nm vesicles secreted by cells, have been studied with respect to cell-to-cell communication, disease diagnosis, and intracellular delivery. The cellular uptake of exosomes occurs by endocytosis; however, the cytosolic release efficiency of encapsulated molecules inside cells is low. To address this issue, here we demonstrate a simple technique for enhancing the cellular uptake and cytosolic release of exosomes by combining a pH-sensitive fusogenic peptide for the fusion of endosomal and exosomal membranes inside cells. This method stimulates the efficient cytosolic release of the exosomal contents with cationic lipids that act as a "glue" to support cellular uptake. Using this simple combined technique, the effective cellular uptake and cytosolic release of an artificially encapsulated dextran macromolecule (70 kDa) in exosomes are achieved, and a marked improvement in bioactivity is attained with the artificially encapsulated ribosome-inactivating protein saporin. Our method will contribute to many biological research fields, including the assessment of the activities of exosomal contents and the development of candidate tools enabling intracellular visualisation and cellular regulation for future therapeutic applications.
authors.affiliation: Nanoscience and Nanotechnology Research Center, Research Organization for the 21st Century, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8570, Japan.
authors.forename: Ikuhiko
authors.initials: I
authors.lastname: Nakase
authors.affiliation: Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Shiroh
authors.initials: S
authors.lastname: Futaki
mesh_terms: D000595:Amino Acid Sequence; D002412:Cations / Q000737:chemistry; D003600:Cytosol / Q000378:metabolism*; D003911:Dextrans / Q000737:chemistry / Q000378:metabolism; D004705:Endocytosis; D055354:Exosomes / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008055:Lipids / Q000737:chemistry*; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D054789:Ribosome Inactivating Proteins, Type 1 / Q000737:chemistry / Q000378:metabolism; D000076985:Saporins; D060149:Tetraspanin 30 / Q000235:genetics / Q000378:metabolism
chemical_list: D002412:Cations; D003911:Dextrans; D008055:Lipids; D010455:Peptides; D054789:Ribosome Inactivating Proteins, Type 1; D060149:Tetraspanin 30; C066951:GALA peptide; D000076985:Saporins