title: Optimization of Morpholino Antisense Oligonucleotides Targeting the Intronic Repressor Element1 in Spinal Muscular Atrophy.
abstract: Loss of Survival Motor Neuron-1 (SMN1) causes Spinal Muscular Atrophy, a devastating neurodegenerative disease. SMN2 is a nearly identical copy gene; however SMN2 cannot prevent disease development in the absence of SMN1 since the majority of SMN2-derived transcripts are alternatively spliced, encoding a truncated, unstable protein lacking exon 7. Nevertheless, SMN2 retains the ability to produce low levels of functional protein. Previously we have described a splice-switching Morpholino antisense oligonucleotide (ASO) sequence that targets a potent intronic repressor, Element1 (E1), located upstream of SMN2 exon 7. In this study, we have assessed a novel panel of Morpholino ASOs with the goal of optimizing E1 ASO activity. Screening for efficacy in the SMNΔ7 mouse model, a single ASO variant was more active in vivo compared with the original E1(MO)-ASO. Sequence variant eleven (E1(MOv11)) consistently showed greater efficacy by increasing the lifespan of severe Spinal Muscular Atrophy mice after a single intracerebroventricular injection in the central nervous system, exhibited a strong dose-response across an order of magnitude, and demonstrated excellent target engagement by partially reversing the pathogenic SMN2 splicing event. We conclude that Morpholino modified ASOs are effective in modifying SMN2 splicing and have the potential for future Spinal Muscular Atrophy clinical applications.
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.
authors.forename: Erkan Y
authors.initials: EY
authors.lastname: Osman
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Washington
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.|Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Kaifer
authors.affiliation: Department of Biological Sciences, University of Southern California, Los Angeles, California, USA.
authors.forename: Chiara
authors.initials: C
authors.lastname: Mazzasette
authors.affiliation: Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Teresa N
authors.initials: TN
authors.lastname: Patitucci
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.|Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA.
authors.forename: Kyra M
authors.initials: KM
authors.lastname: Florea
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.|Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA.
authors.forename: Madeline E
authors.initials: ME
authors.lastname: Simon
authors.affiliation: Department of Biological Sciences, University of Southern California, Los Angeles, California, USA.
authors.forename: Chien-Ping
authors.initials: CP
authors.lastname: Ko
authors.affiliation: Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Allison D
authors.initials: AD
authors.lastname: Ebert
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.|Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA.
authors.forename: Christian L
authors.initials: CL
authors.lastname: Lorson
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D018390:Gene Targeting; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism; D007438:Introns; D051379:Mice; D018345:Mice, Knockout; D060172:Morpholinos / Q000235:genetics*; D009134:Muscular Atrophy, Spinal / Q000235:genetics* / Q000378:metabolism / Q000401:mortality; D009154:Mutation; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020218:Response Elements; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D060172:Morpholinos; D012333:RNA, Messenger; D055533:Survival of Motor Neuron 1 Protein