title: Effect of combined systemic and local morpholino treatment on the spinal muscular atrophy Δ7 mouse model phenotype.
abstract: BACKGROUND
  Spinal muscular atrophy (SMA) is a fatal motor neuron disease of childhood that is caused by mutations in the SMN1 gene. Currently, no effective treatment is available. One possible therapeutic approach is the use of antisense oligos (ASOs) to redirect the splicing of the paralogous gene SMN2, thus increasing functional SMN protein production. Various ASOs with different chemical properties are suitable for these applications, including a morpholino oligomer (MO) variant with a particularly excellent safety and efficacy profile.
  
  
  OBJECTIVE
  We investigated a 25-nt MO sequence targeting the negative intronic splicing silencer (ISS-N1) 10 to 34 region.
  
  
  METHODS
  We administered a 25-nt MO sequence against the ISS-N1 region of SMN2 (HSMN2Ex7D[-10-34]) in the SMAΔ7 mouse model and evaluated the effect and neuropathologic phenotype. We tested different concentrations (from 2 to 24 nM) and delivery protocols (intracerebroventricular injection, systemic injection, or both). We evaluated the treatment efficacy regarding SMN levels, survival, neuromuscular phenotype, and neuropathologic features.
  
  
  RESULTS
  We found that a 25-nt MO sequence against the ISS-N1 region of SMN2 (HSMN2Ex7D[-10-34]) exhibited superior efficacy in transgenic SMAΔ7 mice compared with previously described sequences. In our experiments, the combination of local and systemic administration of MO (bare or conjugated to octaguanidine) was the most effective approach for increasing full-length SMN expression, leading to robust improvement in neuropathologic features and survival. Moreover, we found that several small nuclear RNAs were deregulated in SMA mice and that their levels were restored by MO treatment.
  
  
  CONCLUSIONS
  These results indicate that MO-mediated SMA therapy is efficacious and can result in phenotypic rescue, providing important insights for further development of ASO-based therapeutic strategies in SMA patients.
authors.affiliation: Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Nizzardo
authors.affiliation: Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Simone
authors.affiliation: Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Salani
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland.
authors.forename: Marc-David
authors.initials: MD
authors.lastname: Ruepp
authors.affiliation: Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Rizzo
authors.affiliation: Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Ruggieri
authors.affiliation: Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Zanetta
authors.affiliation: Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Brajkovic
authors.affiliation: Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon.
authors.forename: Hong M
authors.initials: HM
authors.lastname: Moulton
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Müehlemann
authors.affiliation: Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy.
authors.forename: Nereo
authors.initials: N
authors.lastname: Bresolin
authors.affiliation: Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Giacomo P
authors.initials: GP
authors.lastname: Comi
authors.affiliation: Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy. Electronic address: stefania.corti@unimi.it.
authors.forename: Stefania
authors.initials: S
authors.lastname: Corti
mesh_terms: D000818:Animals; D001519:Behavior / Q000187:drug effects; D004195:Disease Models, Animal; D007267:Injections; D007438:Introns / Q000187:drug effects*; D051379:Mice; D008822:Mice, Transgenic; D060172:Morpholinos / Q000008:administration & dosage* / Q000627:therapeutic use*; D009046:Motor Neurons; D009134:Muscular Atrophy, Spinal / Q000188:drug therapy* / Q000235:genetics; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage* / Q000627:therapeutic use*; D010641:Phenotype; D012326:RNA Splicing; D012342:RNA, Small Nuclear / Q000187:drug effects; D045442:Rotarod Performance Test; D013116:Spinal Cord; D055540:Survival of Motor Neuron 2 Protein / Q000235:genetics*
chemical_list: D060172:Morpholinos; D016376:Oligonucleotides, Antisense; D012342:RNA, Small Nuclear; D055540:Survival of Motor Neuron 2 Protein
keywords: SMAΔ7 mice; morpholino oligomer; spinal muscular atrophy; survival motor neuron; therapy