In 2013, Dr. Martine Barkats and her team at the Institut de Myologie in Paris discovered that a gene transfer vehicle derived from a nonpathogenic virus called AAV9 (adeno-associated virus) was able to transfer genes into the cerebrospinal fluid. Based on these findings, the researchers were able to show that using this method to transfer the SMN1 gene into the cerebrospinal fluid dramatically increased the life span of symptomatic SMA mice.

How SMN gene therapy works

The effectiveness of gene therapy based on the administration of an AAV vector carrying the human SMN1 sequence was demonstrated by Barkats and her team using symptomatic SMA type 1 mice.

SMN gene therapy research

In 2015, Barkats and her team were granted €124,000 to study the role of SMN in muscle resident progenitors, to potentially identify new therapeutic targets for SMA. The muscle defects in SMA are partly due to denervation and that loss of the motor neurons that allow them to contract and relax. Motor neurons are known die because of insufficient SMN, and muscles are known to react to low levels of SMN.

This study aims to discover whether muscles contribute directly to their own problems, independent of the motor neurons, by identifying the role of SMN in a muscle’s satellite cells, which are stem cells that are triggered into action to repair damage done to the muscle. In cases where SMN is absent, the objective is to identify new targets specifically affected in these satellite cells and find out if gene therapy targeted at these cells would benefit muscle damage seen in SMA.

Next steps for SMN gene therapy

Barkats and her team’s main objectives for the near future are to determine the therapeutic window of AAV9-SMN gene therapy in symptomatic SMA mice, explore additional strategies independent of SMN to try to improve the effectiveness of AAV9-SMN gene therapy, and improve the knowledge of the pathophysiological mechanism of SMN, including consideration of the role of SMN in non-nervous tissues or cells.

Read the latest news about SMN Gene Therapy at SMA News Today.

Follow the latest developments for all experimental spinal muscular atrophy treatments on the SMA Therapy Tracker.

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