Article | Published:

Rescue of non-human primates from advanced Sudan ebolavirus infection with lipid encapsulated siRNA

Nature Microbiology volume 1, Article number: 16142 (2016) | Download Citation


Although significant progress has been made in developing therapeutics against Zaire ebolavirus, these therapies do not protect against other Ebola species such as Sudan ebolavirus (SUDV). Here, we describe an RNA interference therapeutic comprising siRNA targeting the SUDV VP35 gene encapsulated in lipid nanoparticle (LNP) technology with increased potency beyond formulations used in TKM-Ebola clinical trials. Twenty-five rhesus monkeys were challenged with a lethal dose of SUDV. Twenty animals received siRNA-LNP beginning at 1, 2, 3, 4 or 5 days post-challenge. VP35-targeting siRNA-LNP treatment resulted in up to 100% survival, even when initiated when fever, viraemia and disease signs were evident. Treatment effectively controlled viral replication, mediating up to 4 log10 reductions after dosing. Mirroring clinical findings, a correlation between high viral loads and fatal outcome was observed, emphasizing the importance of stratifying efficacy according to viral load. In summary, strong survival benefit and rapid control of SUDV replication by VP35-targeting LNP confirm its therapeutic potential in combatting this lethal disease.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    Ebola Situation Report (World Health Organization, 2016);

  2. 2.

    et al. Rapid diagnosis of Ebola hemorrhagic fever by reverse transcription-PCR in an outbreak setting and assessment of patient viral load as a predictor of outcome. J. Virol. 78, 4330–4341 (2004).

  3. 3.

    et al. Vesicular stomatitis virus-based vaccines protect nonhuman primates against aerosol challenge with Ebola and Marburg viruses. Vaccine 26, 6894–6900 (2008).

  4. 4.

    et al. Venezuelan equine encephalitis virus replicon particle vaccine protects nonhuman primates from intramuscular and aerosol challenge with ebolavirus. J. Virol. 87, 4952–4964 (2013).

  5. 5.

    et al. Single-injection vaccine protects nonhuman primates against infection with Marburg virus and three species of Ebola virus. J. Virol. 83, 7296–7304 (2009).

  6. 6.

    et al. Protection of nonhuman primates against two species of Ebola virus infection with a single complex adenovirus vector. Clin. Vaccine Immunol. 17, 572–581 (2010).

  7. 7.

    et al. Therapeutic intervention of Ebola virus infection in rhesus macaques with the MB-003 monoclonal antibody cocktail. Sci. Transl. Med. 5, 199ra113 (2013).

  8. 8.

    et al. Sustained protection against Ebola virus infection following treatment of infected nonhuman primates with ZMAb. Sci. Rep. 3, 3365 (2013).

  9. 9.

    et al. Reversion of advanced Ebola virus disease in nonhuman primates with ZMapp. Nature 514, 47–53 (2014).

  10. 10.

    et al. A single phosphorodiamidate morpholino oligomer targeting VP24 protects rhesus monkeys against lethal Ebola virus infection. mBio 6, e02344-14 (2015).

  11. 11.

    et al. Identification of a new ribonucleoside inhibitor of Ebola virus replication. Viruses 7, 6233–6240 (2015).

  12. 12.

    et al. Pan-ebolavirus and pan-filovirus mouse monoclonal antibodies protection against Ebola and Sudan viruses. J. Virol. 90, 266–278 (2015).

  13. 13.

    et al. Macaque monoclonal antibodies targeting novel conserved epitopes within filovirus glycoprotein. J. Virol. 90, 279–291(2015).

  14. 14.

    et al. Bispecific antibody affords complete post-exposure protection of mice from both Ebola (Zaire) and Sudan viruses. Sci. Rep. 6, 19193 (2016).

  15. 15.

    et al. Discovery of an antibody for pan-ebolavirus therapy. Sci. Rep. 6, 20514 (2016).

  16. 16.

    et al. Antibody treatment of Ebola and Sudan virus infection via a uniquely exposed epitope within the glycoprotein receptor-binding site. Cell Rep. 15, 1514–1526 (2016).

  17. 17.

    Current issues of RNAi therapeutics delivery and development. J. Control Rel. 195, 49–54 (2014).

  18. 18.

    et al. Postexposure protection of non-human primates against a lethal Ebola virus challenge with RNA interference: a proof-of-concept study. Lancet 375, 1896–1905 (2010).

  19. 19.

    et al. Marburg virus infection in nonhuman primates: therapeutic treatment by lipid-encapsulated siRNA. Sci. Transl. Med. 6, 250ra116 (2014).

  20. 20.

    et al. Lipid nanoparticle siRNA treatment of Ebola-virus-Makona-infected nonhuman primates. Nature 521, 362–365 (2015).

  21. 21.

    et al. Experimental treatment of Ebola virus disease with TKM-130803 A single arm phase 2 clinical trial. PLoS Med. 13, e1001997 (2016).

  22. 22.

    et al. Early clinical sequelae of Ebola virus disease in Sierra Leone: a cross-sectional study. Lancet Infect Dis. 16, 331–338 (2015).

  23. 23.

    et al. Long-term sequelae after Ebola virus disease in Bundibugyo, Uganda: a retrospective cohort study. Lancet Infect. Dis. 15, 905–912 (2015).

  24. 24.

    et al. Ebola virus persistence in semen of male survivors. Clin. Inf. Dis. 62, 1552–1555 (2016).

  25. 25.

    et al. Ebola virus disease complications as experienced by survivors in Sierra Leone. Clin. Inf. Dis. 62, 1360–1366 (2016).

  26. 26.

    et al. Mutations abrogating VP35 interaction with double-stranded RNA render Ebola virus avirulent in guinea pigs. J. Virol. 84, 3004–3015 (2010).

  27. 27.

    et al. The Ebola virus VP35 protein inhibits activation of interferon regulatory factor 3. J. Virol. 77, 7945–7956 (2003).

  28. 28.

    , , & The VP35 protein of Ebola virus inhibits the antiviral effect mediated by double-stranded RNA-dependent protein kinase PKR. J. Virol. 81, 182–192 (2007).

  29. 29.

    et al. Ebola virus VP35 protein binds double-stranded RNA and inhibits alpha/beta interferon production induced by RIG-I signaling. J. Virol. 80, 5168–5178 (2006).

  30. 30.

    et al. Protection against lethal Marburg virus infection mediated by lipid encapsulated small interfering RNA. J. Infect. Dis. 209, 562–570 (2014).

  31. 31.

    , , & Design of noninflammatory synthetic siRNA mediating potent gene silencing in vivo. Mol. Ther. 13, 494–505 (2006).

  32. 32.

    & Overcoming the innate immune response to small interfering RNA. Hum. Gene Ther. 19, 111–124 (2008).

  33. 33.

    & Complete genome sequence of an Ebola virus (Sudan species) responsible for a 2000 outbreak of human disease in Uganda. Virus Res. 113, 16–25 (2005).

  34. 34.

    et al. Rational design of cationic lipids for siRNA delivery. Nat. Biotechnol. 28, 172–176 (2010).

  35. 35.

    et al. Structural basis for dsRNA recognition and interferon antagonism by Ebola VP35. Nat. Struct. Mol. Biol. 17, 165–172 (2010).

  36. 36.

    , , , & Ebolavirus VP24 binding to karyopherins is required for inhibition of interferon signaling. J. Virol. 84, 1169–1175 (2010).

  37. 37.

    et al. Ebola virus VP24 binds karyopherin α1 and blocks STAT1 nuclear accumulation. J. Virol. 80, 5156–5167 (2006).

  38. 38.

    , & The Ebolavirus VP24 protein blocks phosphorylation of p38 mitogen-activated protein kinase. J. Infect. Dis. 204, (Suppl. 3), S953–S956 (2011).

  39. 39.

    et al. Different temporal effects of Ebola virus VP35 and VP24 proteins on global gene expression in human dendritic cells. J. Virol. 89, 7567–7583 (2015).

  40. 40.

    et al. The Ebola virus VP35 protein is a suppressor of RNA silencing. PLoS Pathogens 3, e86 (2007).

  41. 41.

    , , & Ebolavirus proteins suppress the effects of small interfering RNA by direct interaction with the mammalian RNA interference pathway. J. Virol. 85, 2512–2523 (2011).

  42. 42.

    et al. Late Ebola virus relapse causing meningoencephalitis: a case report. Lancet 388, 498–503 (2016).

  43. 43.

    et al. Ebola viral load at diagnosis associates with patient outcome and outbreak evolution. J. Clin. Invest. 125, 4421–4428 (2015).

  44. 44.

    et al. The contribution of Ebola viral load at admission and other patient characteristics to mortality in a Médecins sans Frontières Ebola case management centre, Kailahun, Sierra Leone, June–October 2014. J. Infect. Dis. 212, 1752–1758 (2015).

  45. 45.

    et al. Clinical illness and outcomes in patients with Ebola in Sierra Leone. N. Engl. J. Med. 371, 2092–2100 (2014).

  46. 46.

    et al. Ebola virus disease complicated by late-onset encephalitis and polyarthritis, Sierra Leone. Emerg. Infect. Dis. 22, 150–152 (2016).

  47. 47.

    & Spermatogenic transmission of the ‘Marburg virus’. (Causes of ‘Marburg simian disease’). Klinische Wochenschrift 46, 398–400 (1968).

  48. 48.

    et al. Molecular evidence of sexual transmission of Ebola virus. N. Engl. J. Med. 373, 2448–2454 (2015).

  49. 49.

    et al. Ebola RNA persistence in semen of Ebola virus disease survivors—preliminary report. N. Engl. J. Med. (2015).

  50. 50.

    et al. Formulated minimal-length synthetic small hairpin RNAs are potent inhibitors of hepatitis C virus in mice with humanized livers. Gastroenterology 146, 63–66 (2014).

Download references


The authors thank V. Borisevich for assistance with clinical pathology assays performed in the GNL BSL-4 laboratory, J. Heyes and K. Lam for data comparing endogenous gene silencing potency across LNP formulations, and S. Klassen for his assistance with siRNA-LNP preparation. This study was supported by the Department of Health and Human Services, National Institutes of Health grant no. U19AI109711 to T.W.G. and E.P.T., and UC7AI094660 for BSL-4 operations support of the Galveston National Laboratory.

Author information

Author notes

    • Thomas W. Geisbert
    •  & Chad E. Mire

    These authors contributed equally to this work.


  1. Arbutus Biopharma Corporation, Burnaby, British Columbia V5J 5J8, Canada

    • Emily P. Thi
    • , Amy C. H. Lee
    • , Raul Ursic-Bedoya
    • , Marjorie Robbins
    • , Andrew S. Kondratowicz
    •  & Ian MacLachlan
  2. Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas 77550, USA

    • Joan B. Geisbert
    • , Krystle N. Agans
    • , Daniel J. Deer
    • , Karla A. Fenton
    • , Thomas W. Geisbert
    •  & Chad E. Mire
  3. Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA

    • Joan B. Geisbert
    • , Krystle N. Agans
    • , Daniel J. Deer
    • , Karla A. Fenton
    • , Thomas W. Geisbert
    •  & Chad E. Mire


  1. Search for Emily P. Thi in:

  2. Search for Amy C. H. Lee in:

  3. Search for Joan B. Geisbert in:

  4. Search for Raul Ursic-Bedoya in:

  5. Search for Krystle N. Agans in:

  6. Search for Marjorie Robbins in:

  7. Search for Daniel J. Deer in:

  8. Search for Karla A. Fenton in:

  9. Search for Andrew S. Kondratowicz in:

  10. Search for Ian MacLachlan in:

  11. Search for Thomas W. Geisbert in:

  12. Search for Chad E. Mire in:


R.U.-B. and M.R. designed the siRNA and R.U.-B. conducted the dual luciferase reporter studies. R.U.-B., C.E.M., M.R., I.M. and T.W.G. designed the in vitro infection study. K.N.A. and C.E.M. performed the in vitro infection study. E.P.T., C.E.M., A.C.H.L., I.M. and T.W.G. conceived and designed the NHP studies. C.E.M., J.B.G., D.J.D. and T.W.G. performed the NHP challenge and treatment experiments and conducted clinical observations of the animals. J.B.G., K.N.A. and D.J.D. performed the clinical pathology assays. J.B.G. performed the SUDV infectivity assays. C.E.M. and K.N.A. performed the PCR assays. E.P.T., C.E.M., J.B.G., K.N.A., D.J.D., K.A.F., A.S.K, A.C.H.L. and T.W.G. analysed the data. K.A.F. performed histological and immunohistochemical analysis of the data. E.P.T., C.E.M., A.C.H.L. and T.W.G. wrote the paper. All authors had access to all of the data and approved the final version of the manuscript.

Competing interests

A.L., I.M. and T.W.G. claim intellectual property regarding RNA interference for the treatment of filovirus infections. I.M. and T.W.G. are co-inventors on US patent 7,838,658 (‘siRNA silencing of filovirus gene expression’) and A.L., I.M. and T.W.G. are co-inventors on US patent 8,716,464 (‘Compositions and methods for silencing Ebola virus gene expression’). The other authors declare no competing interests. Opinions, interpretations, conclusions and recommendations are those of the authors and are not necessarily endorsed by the University of Texas Medical Branch.

Corresponding author

Correspondence to Thomas W. Geisbert.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Table 1, Supplementary Figures 1-5

About this article

Publication history





Further reading