Gene therapy strategies for Spinal Muscular Atrophy.

Research output: ThesisDoctoral Thesis

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Spinal muscular atrophy (SMA), the most common genetic disorder resulting in infantile death, is caused by defective production of the Survival Motor Neuron (SMN) protein encoded by SMN1, leading to degeneration of motor neurons (MNs) and neuromuscular dysfunction within months of birth in the most severe cases. Two licensed treatments are now available; one antisense oligonucleotide and one adeno-associated virus serotype 9 (AAV9) encoding SMN1. The pre-clinical development of these two therapies was investigated here in a systematic review and meta-analysis, showing an overall significant improvement in survival following the treatment of SMA models with these agents. Integration-deficient lentiviral vectors (IDLVs) are highly efficient tools for delivering therapeutic genes, representing an alternative therapeutic avenue. This thesis describes the in vitro characterisation of IDLVs expressing codon-optimised SMN1 under three transcriptional controls (CMV, hSYN, hPGK). Neuronal cell lines and severe SMA fibroblasts showed significantly increased SMN protein levels following transduction with IDLVs, as well as significant increases in gem numbers (an endpoint suggestive of functional SMN1 expression). Since MNs are the primary pathological target of SMA, a protocol to differentiate human induced pluripotent stem cells (iPSCs) to MNs was implemented, showing high transduction of the resulting MNs. SMA iPSC MNs recapitulate in vivo characteristics and hallmarks of SMA disease. It was possible to rescue SMN production to supraphysiological levels following transduction with IDLVs, something that was not able to be achieved using an AAV9 encoding an equivalent cassette. Moreover, IDLVs were able to restore gemin proteins in mutant MNs as well. Finally, the extent of DNA damage and apoptosis was examined in SMA cells, as well as attempting to rescue these with IDLV transduction. These findings suggest that IDLVs may be particularly effective tools and could be useful for novel SMA gene therapy approaches.
Original languageEnglish
Awarding Institution
  • Royal Holloway, University of London
  • Yáñez-Muñoz, Rafael J., Supervisor
Thesis sponsors
Award date1 Sept 2020
Publication statusUnpublished - 2020


  • Spinal Muscular Atrophy
  • Gene therapy
  • Lentiviral vectors

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