Characterization of membrane penetration and cytotoxicity of C9orf72-encoding arginine-rich dipeptides

• Published in: Scientific reports 2018-08, Vol.8 (1), p.12740-11, Article 12740
• Main Authors: Kanekura, Kohsuke, Harada, Yuichiro, Fujimoto, Mao, Yagi, Takuya, Hayamizu, Yuhei, Nagaoka, Kentaro, Kuroda, Masahiko
• Format: Article
• Language: English
• Subjects: 13/2; 14; 14/35; 631/378/1689/1285; 631/45/611; 692/617/375/1917/1285; Apoptosis; Arginine; Cell death; Cytotoxicity; Drug delivery; Humanities and Social Sciences; Intracellular; multidisciplinary; Neurotoxicity; Nucleoli; Peptides; Protein structure; Ribonucleic acid; RNA; Science; Science (multidisciplinary); Secondary structure
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-31096-z

Cell-penetrating peptides (CPPs) including arginine-rich peptides are attracting a lot of attention due to their potential as a novel intracellular drug delivery tool without substantial toxicity. On the other hand, disease-associated arginine-rich CPPs, such as poly-PR and poly-GR translated from C9orf72 gene, also efficiently enter neuronal cells and then kill them. Although both non-harmful CPPs and harmful poly-PR/GR penetrate the plasma membrane using same arginine residues, little is known about the factors which determine the toxicity of the pathogenic CPPs. Here, we show that poly-PR and poly-GR, but not other Arg-rich CPPs, specifically distributed to nucleolus via interaction with RNA. Importantly, C9orf72-dipeptides, but not other Arg-rich CPPs, caused inhibition of protein translation and cell death. Raising extracellular pH enhanced the cell penetration of poly-PR. The repeat number of (PR) affected the secondary structure and determined the intracellular delivery rate and neurotoxicity, and enforced intracellular delivery of non-penetrating short poly-PR peptide caused cell death, suggesting that modulation of extracellular environment to inhibit the uptake of Arg-rich dipeptides might be a drug target against poly-PR/GR-mediated neurotoxicity.