Delivery of a read-through inducing compound, TC007, lessens the severity of a SMA animal model

Document Type

Article

Journal/Book Title

Human Molecular Genetics

Publication Date

10-15-2009

Publisher

Oxford University Press

Volume

18

Issue

20

First Page

3906

Last Page

3913

Abstract

Spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality and is caused by the loss of a functional SMN1 gene. In humans, there exists a nearly-identical copy gene known as SMN2 that encodes an identical protein as SMN1, but differs by a silent C to T transition within exon 7. This single nucleotide difference produces an alternatively spliced isoform, SMNΔ7, which encodes a rapidly degraded protein. The absence of the short peptide encoded by SMN exon 7 is critical in the disease development process; however, heterologous sequences can partially compensate for the SMN exon 7 peptide in several cellular assays. Consistent with this, aminoglycosides, compounds that can suppress efficient recognition of stop codons, resulted in significantly increased levels of SMN protein in SMA patient fibroblasts. We now examine the potential therapeutic capabilities of a novel aminoglycoside, TC007. In an intermediate SMA model (Smn−/−; SMN2+/+; SMNΔ7), when delivered directly to the central nervous system (CNS), TC007 induces SMN in both the brain and spinal cord, significantly increases lifespan (∼30%) and increases ventral horn cell number, consistent with its ability to increase SMN levels in induced pluripotent stem cell-derived human SMA motor neuron cultures. Collectively, these experiments are the first in vivo examination of therapeutics for SMA designed to induce read-through of the SMNΔ7 stop codon to show increased benefit by direct administration to the CNS.

Comments

PubMed PMID: 19625298; PubMed Central PMCID: PMC2748896

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