title: Antisense therapeutics for neurofibromatosis type 1 caused by deep intronic mutations.
abstract: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder affecting 1:3,500 individuals. Disease expression is highly variable and complications are diverse. However, currently there is no specific treatment for the disease. NF1 is caused by mutations in the NF1 gene, approximately 2.1% of constitutional mutations identified in our population are deep intronic mutations producing the insertion of a cryptic exon into the mature mRNA. We used antisense morpholino oligomers (AMOs) to restore normal splicing in primary fibroblast and lymphocyte cell lines derived from six NF1 patients bearing three deep intronic mutations in the NF1 gene (c.288+2025T>G, c.5749+332A>G, and c.7908-321C>G). AMOs were designed to target the newly created 5' splice sites to prevent the incorporation of cryptic exons. Our results demonstrate that AMO treatment effectively restored normal NF1 splicing at the mRNA level for the three mutations studied in the different cell lines analyzed. We also found that AMOs had a rapid effect that lasted for several days, acting in a sequence-specific manner and interfering with the splicing mechanism. Finally, to test whether the correction of aberrant NF1 splicing also restored neurofibromin function to wild-type levels, we measured the amount of Ras-GTP after AMO treatment in primary fibroblasts. The results clearly show an AMO-dependent decrease in Ras-GTP levels, which is consistent with the restoration of neurofibromin function. To our knowledge this is the first time that an antisense technique has been used successfully to correct NF1 mutations opening the possibility of a therapeutic strategy for this type of mutation not only for NF1 but for other genetic disorders.
authors.affiliation: Laboratori de Recerca Translacional, Institut Català d'Oncologia-Institut d'Investigació Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Pros
authors.forename: Juana
authors.initials: J
authors.lastname: Fernández-Rodríguez
authors.forename: Belén
authors.initials: B
authors.lastname: Canet
authors.forename: Llúcia
authors.initials: L
authors.lastname: Benito
authors.forename: Aurora
authors.initials: A
authors.lastname: Sánchez
authors.forename: Ana
authors.initials: A
authors.lastname: Benavides
authors.forename: Feliciano J
authors.initials: FJ
authors.lastname: Ramos
authors.forename: María Asunción
authors.initials: MA
authors.lastname: López-Ariztegui
authors.forename: Gabriel
authors.initials: G
authors.lastname: Capellá
authors.forename: Ignacio
authors.initials: I
authors.lastname: Blanco
authors.forename: Eduard
authors.initials: E
authors.lastname: Serra
authors.forename: Conxi
authors.initials: C
authors.lastname: Lázaro
mesh_terms: D017398:Alternative Splicing; D001483:Base Sequence; D015153:Blotting, Western; D002461:Cell Line, Transformed; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007438:Introns / Q000235:genetics; D009025:Morpholines / Q000737:chemistry; D009154:Mutation; D009456:Neurofibromatosis 1 / Q000235:genetics / Q000473:pathology / Q000628:therapy; D025542:Neurofibromin 1 / Q000235:genetics*; D020319:Oligodeoxyribonucleotides, Antisense / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D022821:RNA Splice Sites / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018631:ras Proteins / Q000378:metabolism
chemical_list: D009025:Morpholines; D025542:Neurofibromin 1; D020319:Oligodeoxyribonucleotides, Antisense; D022821:RNA Splice Sites; D018631:ras Proteins