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Brown CR, Gupta S, Qin J, Racie T, He G, Lentini S, Malone R, Yu M, Matsuda S, Shulga-Morskaya S, Nair AV, Theile CS, Schmidt K, Shahraz A, Goel V, Parmar RG, Zlatev I, Schlegel MK, Nair JK, Jayaraman M, Manoharan M, Brown D, Maier MA, Jadhav V. Investigating the pharmacodynamic durability of GalNAc-siRNA conjugates. Nucleic Acids Res 2020; 48:11827-11844. [PMID: 32808038 PMCID: PMC7708070 DOI: 10.1093/nar/gkaa670] [Citation(s) in RCA: 137] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/27/2020] [Accepted: 07/31/2020] [Indexed: 12/12/2022] Open
Abstract
One hallmark of trivalent N-acetylgalactosamine (GalNAc)-conjugated siRNAs is the remarkable durability of silencing that can persist for months in preclinical species and humans. Here, we investigated the underlying biology supporting this extended duration of pharmacological activity. We found that siRNA accumulation and stability in acidic intracellular compartments is critical for long-term activity. We show that functional siRNA can be liberated from these compartments and loaded into newly generated Argonaute 2 protein complexes weeks after dosing, enabling continuous RNAi activity over time. Identical siRNAs delivered in lipid nanoparticles or as GalNAc conjugates were dose-adjusted to achieve similar knockdown, but only GalNAc–siRNAs supported an extended duration of activity, illustrating the importance of receptor-mediated siRNA trafficking in the process. Taken together, we provide several lines of evidence that acidic intracellular compartments serve as a long-term depot for GalNAc–siRNA conjugates and are the major contributor to the extended duration of activity observed in vivo.
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Affiliation(s)
| | - Swati Gupta
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - June Qin
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Timothy Racie
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Guo He
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Scott Lentini
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Ryan Malone
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Mikyung Yu
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | - Anil V Nair
- MGH Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | | | - Karyn Schmidt
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Azar Shahraz
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Varun Goel
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | - Ivan Zlatev
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | | | | | - Dennis Brown
- MGH Program in Membrane Biology, Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | | | - Vasant Jadhav
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
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