Attachment of Cell-Binding Ligands to Arginine-Rich Cell-Penetrating Peptides Enables Cytosolic Translocation of Complexed siRNA. Issue 1 (22nd January 2015)

• Record Type: Journal Article
• Authors: Zeller, Skye; Choi, Chang Seon; Uchil, Pradeep D.; Ban, Hong-Seok; Siefert, Alyssa; Fahmy, Tarek M.; Mothes, Walther; Lee, Sang-Kyung; Kumar, Priti
• Is Part Of: Chemistry & biology. Volume 22:Issue 1(2015)
• Page Start: 50
• Page End: 62
• Publication Date: 2015-01-22
• Subjects: Biochemistry -- Periodicals; 540
• DOI: 10.1016/j.chembiol.2014.11.009
• Languages: English
• ISSNs: 1074-5521

Abstract

Summary: Cell-penetrating peptides (CPPs), such as nona-arginine (9R), poorly translocate siRNA into cells. Our studies demonstrate that attaching 9R to ligands that bind cell surface receptors quantitatively increases siRNA uptake and importantly, allows functional delivery of complexed siRNA. The mechanism involved accumulation of ligand-9R:siRNA microparticles on the cell membrane, which induced transient membrane inversion at the site of ligand-9R binding and rapid siRNA translocation into the cytoplasm. siRNA release also occurred late after endocytosis when the ligand was attached to the L isoform of 9R, but not the protease-resistant 9DR, prolonging mRNA knockdown. This critically depended on endosomal proteolytic activity, implying that partial CPP degradation is required for endosome-to-cytosol translocation. The data demonstrate that ligand attachment renders simple polycationic CPPs effective for siRNA delivery by restoring their intrinsic property of translocation. Graphical Abstract: Highlights: 9D/LR peptides translocate attached protein cargo but not siRNA Ligand attachment to 9D/LR enables siRNA translocation into cytoplasm Ligand-9D/LR binding induces topical membrane inversion Ligand-9LR (but not 9DR) translocates siRNA from late endosomes Abstract : Cell-penetrating peptides like 9R poorly translocate nucleic acids into cells despite their inherent ability to translocate across cell membranes. Zeller et al. explore the mechanism wherein attachment of 9R to a ligand that binds a cell surface receptor transforms 9R into a highly effective siRNA delivery agent.