RNAi prevents and reverses phenotypes induced by mutant human ataxin-1.
OBJECTIVE
Spinocerebellar ataxia type 1 is an autosomal dominant fatal neurodegenerative disease caused by a polyglutamine expansion in the coding region of ATXN1. We showed previously that partial suppression of mutant ataxin-1 (ATXN1) expression, using virally expressed RNAi triggers, could prevent disease symptoms in a transgenic mouse model and a knockin mouse model of the disease, using a single dose of virus. Here, we set out to test whether RNAi triggers targeting ATXN1 could not only prevent, but also reverse disease readouts when delivered after symptom onset.


METHODS
We administered recombinant adeno-associated virus (rAAV) expressing miS1, an artificial miRNA targeting human ATXN1 mRNA (rAAV.miS1), to a mouse model of spinocerebellar ataxia type 1 (SCA1; B05 mice). Viruses were delivered prior to or after symptom onset at multiple doses. Control B05 mice were treated with rAAVs expressing a control artificial miRNA, or with saline. Animal behavior, molecular phenotypes, neuropathology, and magnetic resonance spectroscopy were done on all groups, and data were compared to wild-type littermates.


RESULTS
We found that SCA1 phenotypes could be reversed by partial suppression of human mutant ATXN1 mRNA by rAAV.miS1 when delivered after symptom onset. We also identified the therapeutic range of rAAV.miS1 that could prevent or reverse disease readouts.


CONCLUSIONS
SCA1 disease may be reversible by RNAi therapy, and the doses required for advancing this therapy to humans are delineated. Ann Neurol 2016;80:754-765.
Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA.
Megan S
MS
Keiser
Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA.
Alejandro Mas
AM
Monteys
Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA.|Spark Therapeutics, Philadelphia, PA.
Romuald
R
Corbau
Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA.|Department of Neurology, University of Pennsylvania, Philadelphia, PA.
Pedro
P
Gonzalez-Alegre
Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA.|Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA.
Beverly L
BL
Davidson
D000818:Animals; D000067696:Ataxin-1 / Q000378:metabolism*; D001522:Behavior, Animal; D000229:Dependovirus; D004195:Disease Models, Animal; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D010641:Phenotype; D034622:RNA Interference; D012333:RNA, Messenger; D020754:Spinocerebellar Ataxias / Q000503:physiopathology* / Q000517:prevention & control / Q000628:therapy*
C000593749:ATXN1 protein, human; D000067696:Ataxin-1; D012333:RNA, Messenger
Hum Mol Genet. 2007 Sep 1;16(17):2122-34
17599952
J Neurosci. 1998 Jul 15;18(14):5508-16
9651231
Cell. 1995 Sep 22;82(6):937-48
7553854
Acta Neuropathol. 1995;90(6):572-81
8615077
J Neurochem. 2001 Apr;77(2):408-15
11299303
Neurobiol Dis. 2013 Jun;54:456-63
23376683
Brain Res Mol Brain Res. 1997 Jun;46(1-2):333-7
9191112
Brain Pathol. 1997 Jul;7(3):901-26
9217975
Cerebellum. 2002 Jan-Mar;1(1):19-26
12879970
Mol Ther. 2014 Mar;22(3):588-95
24419082
J Neurosci. 1997 Oct 1;17(19):7385-95
9295384
Nat Genet. 1995 May;10(1):94-8
7647801
Mov Disord. 2010 Jul 15;25(9):1253-61
20310029
Exp Neurol. 2011 Dec;232(2):290-8
21963649
Annu Rev Neurosci. 2007;30:575-621
17417937
Hum Mol Genet. 2004 Oct 15;13(20):2535-43
15317756
Hum Mol Genet. 2000 Mar 22;9(5):779-85
10749985
Neurobiol Dis. 2013 Aug;56:6-13
23583610
Nat Med. 2004 Aug;10(8):816-20
15235598
Brain. 2015 Dec;138(Pt 12):3555-66
26490326
Am J Pathol. 2001 Sep;159(3):905-13
11549583
Mov Disord. 2015 Apr 15;30(5):662-70
25773989
Neuroscience. 2015 Mar 19;289:289-99
25595967
Nucleic Acids Res. 2014 Dec 1;42(21):13315-27
25332397
J Neurosci. 2010 Mar 10;30(10):3831-8
20220018
J Neurosci. 2004 Oct 6;24(40):8853-61
15470152
Brain Res Brain Res Rev. 1989 Apr-Jun;14(2):117-41
2752228
Cell. 1998 Oct 2;95(1):41-53
9778246