Researchers in France have developed a strategy to promote neuronal regeneration after injury.
Researchers moved a step closer to devising a way to repair the central nervous system, something that has long been considered impossible.
Experts from Inserm, the CNRS, and the UPMC have described the novel strategy, developed following the results of in vitro studies, in a PLoS ONE article.
Led by Alain Privat, the Inserm team have shown that an essential component interfering with regeneration was due to the activity of astrocytes, feeder cells that surround neurons.
Normally, the primary role of astrocytes is to supply the nutrients necessary for neuronal function. In the event of spinal injury or lesion, astrocytes synthesize two particular proteins (glial fibrillary acidic protein (GFAP) and vimentin), which isolate the damaged neuron to prevent interference with the operation of the central nervous system.
While the protection is initially useful, in the long run it induces formation of impermeable cicatricial tissue around the neuron, thus constituting impenetrable scarring hostile to axonal regeneration and hence to propagation of nervous impulses. In the event of severe injury, the scarring engenders motor paralysis.
Based on their initial findings, the researchers set out to devise a way to develop a therapeutic instrument to block formation of cicatricial tissue.
They used gene therapy based on use of interfering RNA. The short RNA sequences, which were made to measure, were inserted into the cytoplasm of cultured astrocytes using a viral therapeutic vector.
Once in the cell, the RNA activates mechanisms which block the synthesis of the two proteins secreted by astrocytes and responsible for cicatrix formation.
Using that technique, the researchers succeeded in controlling the reaction of astrocytes, and when the latter were cultured with neurons, they promoted neuronal survival and triggered axonal growth.
The researchers say that their results were validated by in vivo studies.
According to them, they will next try to apply the same method to the mouse.
They hope that, in future, their approach may be used in patients having undergone spinal injury.