title: Nonallele specific silencing of ataxin-7 improves disease phenotypes in a mouse model of SCA7.
abstract: Spinocerebellar ataxia type 7 (SCA7) is a late-onset neurodegenerative disease characterized by ataxia and vision loss with no effective treatments in the clinic. The most striking feature is the degeneration of Purkinje neurons of the cerebellum caused by the presence of polyglutamine-expanded ataxin-7. Ataxin-7 is part of a transcriptional complex, and, in the setting of mutant ataxin-7, there is misregulation of target genes. Here, we designed RNAi sequences to reduce the expression of both wildtype and mutant ataxin-7 to test if reducing ataxin-7 in Purkinje cells is both tolerated and beneficial in an animal model of SCA7. We observed sustained reduction of both wildtype and mutant ataxin-7 as well as a significant improvement of ataxia phenotypes. Furthermore, we observed a reduction in cerebellar molecular layer thinning and nuclear inclusions, a hallmark of SCA7. In addition, we observed recovery of cerebellar transcripts whose expression is disrupted in the presence of mutant ataxin-7. These data demonstrate that reduction of both wildtype and mutant ataxin-7 by RNAi is well tolerated, and contrary to what may be expected from reducing a component of the Spt-Taf9-Gcn5 acetyltransferase complex, is efficacious in the SCA7 mouse.
authors.affiliation: Interdisciplinary program in Genetics, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Pavitra S
authors.initials: PS
authors.lastname: Ramachandran
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Ryan L
authors.initials: RL
authors.lastname: Boudreau
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Kellie A
authors.initials: KA
authors.lastname: Schaefer
authors.affiliation: Department of Pediatrics, Cellular and Molecular Medicine, and Neurosciences, Division of Biological Sciences, the Institute for Genomic Medicine, and the Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, California, USA.
authors.forename: Albert R
authors.initials: AR
authors.lastname: La Spada
authors.affiliation: 1] Interdisciplinary program in Genetics, University of Iowa, Iowa City, Iowa, USA [2] Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA [3] Department of Neurology, University of Iowa, Iowa City, Iowa, USA [4] Department of Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Beverly L
authors.initials: BL
authors.lastname: Davidson
mesh_terms: D000483:Alleles; D000818:Animals; D000067719:Ataxin-7; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics*; D011689:Purkinje Cells / Q000378:metabolism* / Q000473:pathology; D034622:RNA Interference; D020754:Spinocerebellar Ataxias / Q000235:genetics / Q000503:physiopathology* / Q000628:therapy*
chemical_list: D000067719:Ataxin-7; C000593831:Atxn7 protein, mouse; D009419:Nerve Tissue Proteins