Exosome-mediated Delivery of Hydrophobically Modified siRNA for Huntingtin mRNA Silencing

• Published in: Molecular therapy Vol. 24; no. 10; pp. 1836 - 1847
• Main Authors: Didiot, Marie-Cécile, Hall, Lauren M, Coles, Andrew H, Haraszti, Reka A, Godinho, Bruno MDC, Chase, Kathryn, Sapp, Ellen, Ly, Socheata, Alterman, Julia F, Hassler, Matthew R, Echeverria, Dimas, Raj, Lakshmi, Morrissey, David V, DiFiglia, Marian, Aronin, Neil, Khvorova, Anastasia
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-10-2016; Elsevier Limited; Nature Publishing Group
• Subjects: Animals; Cells, Cultured; Cholesterol; Drug dosages; Exosomes - genetics; Gene Expression Regulation; Gene Silencing; Genetic Therapy; Humans; Huntingtin Protein - genetics; Huntingtin Protein - metabolism; Huntingtons disease; Hydrophobic and Hydrophilic Interactions; Kinases; Medical schools; Mice; Microscopy; Neurons - metabolism; Original; Proteins; RNA, Small Interfering - administration & dosage; RNA, Small Interfering - chemistry; RNA, Small Interfering - pharmacology; United States > US; Massachusetts
• ISSN: 1525-0016; 1525-0024
• DOI: 10.1038/mt.2016.126

Delivery represents a significant barrier to the clinical advancement of oligonucleotide therapeutics for the treatment of neurological disorders, such as Huntington's disease. Small, endogenous vesicles known as exosomes have the potential to act as oligonucleotide delivery vehicles, but robust and scalable methods for loading RNA therapeutic cargo into exosomes are lacking. Here, we show that hydrophobically modified small interfering RNAs (hsiRNAs) efficiently load into exosomes upon co-incubation, without altering vesicle size distribution or integrity. Exosomes loaded with hsiRNAs targeting Huntingtin mRNA were efficiently internalized by mouse primary cortical neurons and promoted dose-dependent silencing of Huntingtin mRNA and protein. Unilateral infusion of hsiRNA-loaded exosomes, but not hsiRNAs alone, into mouse striatum resulted in bilateral oligonucleotide distribution and statistically significant bilateral silencing of up to 35% of Huntingtin mRNA. The broad distribution and efficacy of hsiRNA-loaded exosomes delivered to brain is expected to advance the development of therapies for the treatment of Huntington's disease and other neurodegenerative disorders.