Sahashi, K., Ling, K. K., Hua, Y., Wilkinson, J. E., Nomakuchi, T., Rigo, F., Hung, G., Xu, D., Jiang, Y. P., Lin, R. Z., Ko, C. P., Bennett, C. F., Krainer, A. R. (September 2013) Pathological impact of SMN2 mis-splicing in adult SMA mice. EMBO Molecular Medicine, 5 (10). pp. 1586-1601. ISSN 17574676 (ISSN)
Abstract
Loss-of-function mutations in SMN1 cause spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. The related SMN2 gene expresses suboptimal levels of functional SMN protein, due to a splicing defect. Many SMA patients reach adulthood, and there is also adult-onset (type IV) SMA. There is currently no animal model for adult-onset SMA, and the tissue-specific pathogenesis of post-developmental SMN deficiency remains elusive. Here, we use an antisense oligonucleotide (ASO) to exacerbate SMN2 mis-splicing. Intracerebroventricular ASO injection in adult SMN2-transgenic mice phenocopies key aspects of adult-onset SMA, including delayed-onset motor dysfunction and relevant histopathological features. SMN2 mis-splicing increases during late-stage disease, likely accelerating disease progression. Systemic ASO injection in adult mice causes peripheral SMN2 mis-splicing and affects prognosis, eliciting marked liver and heart pathologies, with decreased IGF1 levels. ASO dose-response and time-course studies suggest that only moderate SMN levels are required in the adult central nervous system, and treatment with a splicing-correcting ASO shows a broad therapeutic time window. We describe distinctive pathological features of adult-onset and early-onset SMA.
Actions (login required)
 |
Administrator's edit/view item |