Abstract
Spherical nucleic acids (SNAs) are nanostructures formed by chemically conjugating short linear strands of oligonucleotides to a nanoparticle template. When made with modified small interfering RNA (siRNA) duplexes, SNAs act as single-entity transfection and gene silencing agents and have been used as lead therapeutic constructs in several disease models. However, the manner in which modified siRNA duplex strands that comprise the SNA lead to gene silencing is not understood. Herein, a systematic analysis of siRNA biochemistry involving SNAs shows that Dicer cleaves the modified siRNA duplex from the surface of the nanoparticle, and the liberated siRNA subsequently functions in a way that is dependent on the canonical RNA interference mechanism. By leveraging this understanding, a class of SNAs was chemically designed which increases the siRNA content by an order of magnitude through covalent attachment of each strand of the duplex. As a consequence of increased nucleic acid content, this nanostructure architecture exhibits less cell cytotoxicity than conventional SNAs without a decrease in siRNA activity.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1312-1320 |
| Number of pages | 9 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 117 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jan 21 2020 |
Funding
ACKNOWLEDGMENTS. The work was supported by National Cancer Institute grants U54CA199091, P50CA221747, and R01CA208783 awarded to C.A.M. and National Institute of General Medical Sciences grant R35GM118144 awarded to R.W.C. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The project was also supported by the Prostate Cancer Foundation and the Movember Foundation (17CHAL08) awarded to C.A.M. G.Y. gratefully acknowledges support from the Chemistry of Life Processes T32GM105538 at Northwestern University. D.M.P. was supported by a Pew Latin American Postdoctoral Fellowship. G.Y. thanks Kevin Nyberg and Shelby Blythe for their help with the Drosophila embryo injections. This work made use of the Integrated Molecular Structure Education and Research Center and Keck Biophysics Facility at Northwestern University, which has received support from Northwestern University and the State of Illinois. The content is solely the responsibility of the authors and does not necessarily represent the official views of Northwestern University.
Keywords
- Gene regulation
- SiRNA processing
- Spherical nucleic acids
ASJC Scopus subject areas
- General