Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

RNAi-mediated gene silencing in non-human primates


The opportunity to harness the RNA interference (RNAi) pathway to silence disease-causing genes holds great promise for the development of therapeutics directed against targets that are otherwise not addressable with current medicines1,2. Although there are numerous examples of in vivo silencing of target genes after local delivery of small interfering RNAs (siRNAs)3,4,5, there remain only a few reports of RNAi-mediated silencing in response to systemic delivery of siRNA6,7,8, and there are no reports of systemic efficacy in non-rodent species. Here we show that siRNAs, when delivered systemically in a liposomal formulation, can silence the disease target apolipoprotein B (ApoB) in non-human primates. APOB-specific siRNAs were encapsulated in stable nucleic acid lipid particles (SNALP) and administered by intravenous injection to cynomolgus monkeys at doses of 1 or 2.5 mg kg-1. A single siRNA injection resulted in dose-dependent silencing of APOB messenger RNA expression in the liver 48 h after administration, with maximal silencing of >90%. This silencing effect occurred as a result of APOB mRNA cleavage at precisely the site predicted for the RNAi mechanism. Significant reductions in ApoB protein, serum cholesterol and low-density lipoprotein levels were observed as early as 24 h after treatment and lasted for 11 days at the highest siRNA dose, thus demonstrating an immediate, potent and lasting biological effect of siRNA treatment. Our findings show clinically relevant RNAi-mediated gene silencing in non-human primates, supporting RNAi therapeutics as a potential new class of drugs.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Figure 1: SNALP–siRNA-mediated silencing of murine Apob is potent, specific, dose-dependent and long-lasting.
Figure 2: Systemic silencing of APOB mRNA in non-human primates.
Figure 3: Phenotypic effects of RNAi-mediated silencing of APOB mRNA in non-human primates.

Similar content being viewed by others


  1. Novina, C. D. & Sharp, P. A. The RNAi revolution. Nature 430, 161–164 (2004)

    Article  ADS  CAS  Google Scholar 

  2. Shankar, P., Manjunath, N. & Lieberman, J. The prospect of silencing disease using RNA interference. J. Am. Med. Assoc. 293, 1367–1373 (2005)

    Article  CAS  Google Scholar 

  3. Thakker, D. R. et al. Neurochemical and behavioral consequences of widespread gene knockdown in the adult mouse brain by using nonviral RNA interference. Proc. Natl Acad. Sci. USA 101, 17270–17275 (2004)

    Article  ADS  CAS  Google Scholar 

  4. Bitko, V., Musiyenko, A., Shulyayeva, O. & Barik, S. Inhibition of respiratory viruses by nasally administered siRNA. Nature Med. 11, 50–55 (2005)

    Article  CAS  Google Scholar 

  5. Palliser, D. et al. An siRNA-based microbicide protects mice from lethal herpes simplex virus 2 infection. Nature 439, 89–94 (2006)

    Article  ADS  CAS  Google Scholar 

  6. Soutschek, J. et al. Therapeutic silencing of an endogenous gene by systemic administration of modified siRNAs. Nature 432, 173–178 (2004)

    Article  ADS  CAS  Google Scholar 

  7. Song, E. et al. Antibody mediated in vivo delivery of small interfering RNAs via cell-surface receptors. Nature Biotechnol. 23, 709–717 (2005)

    Article  CAS  Google Scholar 

  8. Morrissey, D. V. et al. Potent and persistent in vivo anti-HBV activity of chemically modified siRNAs. Nature Biotechnol. 23, 1002–1007 (2005)

    Article  CAS  Google Scholar 

  9. Brown, M. S. & Goldstein, J. L. A receptor-mediated pathway for cholesterol homeostasis. Science 232, 34–47 (1986)

    Article  ADS  CAS  Google Scholar 

  10. Cannon, C. P. et al. Intensive versus moderate lipid lowering with statins after acute coronary syndromes. N. Engl. J. Med. 350, 1495–1504 (2004)

    Article  CAS  Google Scholar 

  11. Ridker, P. M. et al. C-reactive protein levels and outcomes after statin therapy. N. Engl. J. Med. 352, 20–28 (2005)

    Article  CAS  Google Scholar 

  12. Crooke, R. M. et al. An apolipoprotein B antisense oligonucleotide lowers LDL cholesterol in hyperlipidemic mice without causing hepatic steatosis. J. Lipid Res. 46, 872–884 (2005)

    Article  CAS  Google Scholar 

  13. Song, E. et al. Sustained small interfering RNA-mediated human immunodeficiency virus type 1 inhibition in primary macrophages. J. Virol. 77, 7174–7181 (2003)

    Article  CAS  Google Scholar 

  14. Bartlett, D. W. & Davis, M. E. Insights into the kinetics of siRNA-mediated gene silencing from live-cell and live-animal bioluminescent imaging. Nucleic Acids Res. 34, 322–333 (2006)

    Article  CAS  Google Scholar 

  15. Lennernas, H. & Fager, G. Pharmacodynamics and pharmacokinetics of the HMG-CoA reductase inhibitors. Similarities and differences. Clin. Pharmacokinet. 32, 403–425 (1997)

    Article  CAS  Google Scholar 

  16. Levin, A. A. A review of the issues in the pharmacokinetics and toxicology of phosphorothioate antisense oligonucleotides. Biochim. Biophys. Acta 1489, 69–84 (1999)

    Article  CAS  Google Scholar 

  17. Chonn, A., Cullis, P. R. & Devine, D. V. The role of surface charge in the activation of the classical and alternative pathways of complement by liposomes. J. Immunol. 146, 4234–4241 (1991)

    CAS  PubMed  Google Scholar 

  18. Hornung, V. et al. Sequence-specific potent induction of IFN-α by short interfering RNA in plasmacytoid dendritic cells through TLR7. Nature Med. 11, 263–270 (2005)

    Article  CAS  Google Scholar 

  19. Judge, A. D. et al. Sequence-dependent stimulation of the mammalian innate immune response by synthetic siRNA. Nature Biotechnol. 23, 457–462 (2005)

    Article  CAS  Google Scholar 

Download references


We are grateful to P. Sharp, J. Maraganore and N. Mahanthappa for their assistance and support in this study. We would also like to thank W. J. Schneider, J. Frohlich, M. Hayden and J. E. Vance for discussions. We acknowledge the technical assistance of C. Woppmann and A. Wetzel, and thank V. Kesavan and G. Wang for preparation of the cholesterol-conjugated siRNA used in this study. Finally, we thank S. Young for providing anti-ApoB antibodies. This work was supported by grants from the National Science and Engineering Research Council of Canada (to A.J.W. and M.N.F.). Author Contributions This work represents the outcome of a collaboration between scientists at Alnylam Pharmaceuticals and Protiva Biotherapeutics Inc.

Author information

Authors and Affiliations


Corresponding authors

Correspondence to Tracy S. Zimmermann or Ian MacLachlan.

Ethics declarations

Competing interests

The authors of this paper are employees of either Alnylam Pharmaceuticals or Protiva Biotherapeutics Inc., and therefore declare competing financial interests.

Supplementary information

Supplementary Methods

This file contains details of experimental methods used in this study. (PDF 37 kb)

Supplementary Figures and Table

This file contains Supplementary Figures 1–6 with their legends and Supplementary Table 1. (PDF 127 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Zimmermann, T., Lee, A., Akinc, A. et al. RNAi-mediated gene silencing in non-human primates. Nature 441, 111–114 (2006).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing