Australasian Science: Australia's authority on science since 1938

Epilepsy Cure from a Tarantula

A key ingredient in tarantula venom has been identified as a potential treatment for a devastating form of genetic epilepsy.

Dravet syndrome affects young children before their first birthday. Children live with a range of very serious symptoms, including delayed mental and behavioural development, and daily seizures. The disease can result in early death.

Dravet syndrome is caused by a mutation in the SCN1A gene, which produces a protein that calms electrical activity in the brain. Children with a mutation in one copy of the SCN1A gene only have half the normal amount of this protein, so the brain is overactive. This results in seizures and the other features of Dravet syndrome.

“We reasoned that if we could just make the remaining protein work harder, it would effectively pick up the slack – much like a cyclist on a tandem bicycle can help her exhausted passenger by pedalling harder to maintain speed,” says Prof Steven Petrou of the Florey Institute of Neuroscience and Mental Health.

The researchers realised that the venom of the West African tarantula (Heteroscodra maculata) contains a small peptide called Hm1a that hyper-stimulates the protein affected in Dravet patients.

Before treatment with Hm1a, young Dravet mice displayed reduced activity in a specific type of brain cell whose job it is to reduce overall brain activity. However, treatment with the tarantula venom peptide recovered neuronal activity to normal levels, which stopped seizures and prevented early mortality.

“After applying the compound from the spider venom to nerve cells from the brains of Dravet mice, we saw their activity immediately return to normal. Infusion into the brains of the Dravet mice not only restored normal brain function within minutes, but over 3 days we noted a dramatic reduction in seizures in the mice and increased survival. Every single untreated mouse died.”

The results were published in the Proceedings of the National Academy of Sciences (https://goo.gl/68tDcv).