title: Targeted degradation of sense and antisense C9orf72 RNA foci as therapy for ALS and frontotemporal degeneration.
abstract: Expanded hexanucleotide repeats in the chromosome 9 open reading frame 72 (C9orf72) gene are the most common genetic cause of ALS and frontotemporal degeneration (FTD). Here, we identify nuclear RNA foci containing the hexanucleotide expansion (GGGGCC) in patient cells, including white blood cells, fibroblasts, glia, and multiple neuronal cell types (spinal motor, cortical, hippocampal, and cerebellar neurons). RNA foci are not present in sporadic ALS, familial ALS/FTD caused by other mutations (SOD1, TDP-43, or tau), Parkinson disease, or nonneurological controls. Antisense oligonucleotides (ASOs) are identified that reduce GGGGCC-containing nuclear foci without altering overall C9orf72 RNA levels. By contrast, siRNAs fail to reduce nuclear RNA foci despite marked reduction in overall C9orf72 RNAs. Sustained ASO-mediated lowering of C9orf72 RNAs throughout the CNS of mice is demonstrated to be well tolerated, producing no behavioral or pathological features characteristic of ALS/FTD and only limited RNA expression alterations. Genome-wide RNA profiling identifies an RNA signature in fibroblasts from patients with C9orf72 expansion. ASOs targeting sense strand repeat-containing RNAs do not correct this signature, a failure that may be explained, at least in part, by discovery of abundant RNA foci with C9orf72 repeats transcribed in the antisense (GGCCCC) direction, which are not affected by sense strand-targeting ASOs. Taken together, these findings support a therapeutic approach by ASO administration to reduce hexanucleotide repeat-containing RNAs and raise the potential importance of targeting expanded RNAs transcribed in both directions.
authors.affiliation: Departments of Neurosciences, Cellular and Molecular Medicine, and Pathology, and Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093.
authors.forename: Clotilde
authors.initials: C
authors.lastname: Lagier-Tourenne
authors.forename: Michael
authors.initials: M
authors.lastname: Baughn
authors.forename: Frank
authors.initials: F
authors.lastname: Rigo
authors.forename: Shuying
authors.initials: S
authors.lastname: Sun
authors.forename: Patrick
authors.initials: P
authors.lastname: Liu
authors.forename: Hai-Ri
authors.initials: HR
authors.lastname: Li
authors.forename: Jie
authors.initials: J
authors.lastname: Jiang
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Watt
authors.forename: Seung
authors.initials: S
authors.lastname: Chun
authors.forename: Melanie
authors.initials: M
authors.lastname: Katz
authors.forename: Jinsong
authors.initials: J
authors.lastname: Qiu
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.forename: Shuo-Chien
authors.initials: SC
authors.lastname: Ling
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhu
authors.forename: Magdalini
authors.initials: M
authors.lastname: Polymenidou
authors.forename: Kevin
authors.initials: K
authors.lastname: Drenner
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Artates
authors.forename: Melissa
authors.initials: M
authors.lastname: McAlonis-Downes
authors.forename: Sebastian
authors.initials: S
authors.lastname: Markmiller
authors.forename: Kasey R
authors.initials: KR
authors.lastname: Hutt
authors.forename: Donald P
authors.initials: DP
authors.lastname: Pizzo
authors.forename: Janet
authors.initials: J
authors.lastname: Cady
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Harms
authors.forename: Robert H
authors.initials: RH
authors.lastname: Baloh
authors.forename: Scott R
authors.initials: SR
authors.lastname: Vandenberg
authors.forename: Gene W
authors.initials: GW
authors.lastname: Yeo
authors.forename: Xiang-Dong
authors.initials: XD
authors.lastname: Fu
authors.forename: C Frank
authors.initials: CF
authors.lastname: Bennett
authors.forename: Don W
authors.initials: DW
authors.lastname: Cleveland
authors.forename: John
authors.initials: J
authors.lastname: Ravits
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000188:drug therapy* / Q000235:genetics; D000818:Animals; D015139:Blotting, Southern; D000073885:C9orf72 Protein; D002490:Central Nervous System / Q000166:cytology / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D042622:DNA Repeat Expansion / Q000235:genetics*; D005347:Fibroblasts / Q000378:metabolism; D057174:Frontotemporal Lobar Degeneration / Q000188:drug therapy* / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods*; D005838:Genotype; D017404:In Situ Hybridization, Fluorescence; D051379:Mice; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage / Q000235:genetics / Q000494:pharmacology* / Q000627:therapeutic use; D011506:Proteins / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D017423:Sequence Analysis, RNA
chemical_list: D000073885:C9orf72 Protein; C568651:C9orf72 protein, human; D017931:DNA Primers; D016376:Oligonucleotides, Antisense; D011506:Proteins