Tarantula venom offers epilepsy treatment clue

An international team led by Australian scientists has used a peptide isolated from the venom of the West African tarantula (Heteroscodra maculate) to treat Dravet syndrome, a severe form of epilepsy that affects children in the first year of life.

The research, published in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS), was conducted using mice and should not – at least yet – be interpreted as offering a treatment in humans.

Dravet syndrome can cause intellectual disabilities, multiple daily seizures and early death. It is driven by a mutation in a gene that produces a protein called critical for calming the electrical activity of the brain through the effect of cells known as inhibitory interneurons. Sufferers have only half the normal amount of the protein, resulting in an overactive brain.

“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 Steven Petrou from the Florey Institute of Neuroscience and Mental Health in Melbourne, Australia.

The idea of using tarantula venom came from one of Petrou’s collaborators, Glenn King from the Institute for Molecular Bioscience at the University of Queensland, also in Australia. He studies the chemistry of venoms from a range of arthropod predators, including spiders, scorpions and centipedes, for their potential to treat chronic pain, epilepsy and stroke.

In the recent study, young Dravet-susceptible mice were given a peptide, called Hm1ar, derived from tarantula venom, which immediately boosted inhibitory interneuron activity to normal levels.

“Infusion into the brains of the Dravet mice not only restored normal brain function within minutes, but over three days we noted a dramatic reduction in seizures in the mice and increased survival,” Petrou says. “Every single untreated mouse died.”