From venom to medicine
Researchers at the Institut des biomolécules Max Mousseron (IBMM) are turning poisons into medicines: they are sifting through animal venoms in search of new therapeutic molecules.
Snakes, scorpions, spiders, cones... These animals secrete extremely powerful venoms, enabling them to kill their prey in a matter of seconds. But these deadly elixirs are also a tremendous source of hope: researchers are studying these venoms to develop new medicines. The idea of using animal venoms for medicinal purposes is not new: decoctions of snake venom have been used in traditional Chinese medicine since antiquity. But systematic pharmacological research into these molecules is much more recent. " It's only in the last twenty years or so that we've seen any real development in this area ", explains Sébastien Dutertre, a researcher at IBMM.
Poisons that heal
This work led to the development of new drugs, some of which are now indispensable. Captopril, a drug now prescribed to thousands of patients suffering from hypertension, has its origins in the fangs of Bothrops jararaca, a fearsome viper abundant in Brazil. The venom of this "spearhead viper" is devastating. Researchers have discovered that it causes blood vessels to dilate, resulting in a drop in blood pressure - a particularly interesting property for patients suffering from hypertension.
Another drug on the shelves of our pharmacies is Byetta, prescribed to patients suffering from type 2 diabetes. The active molecule was identified in the saliva of the "Gila monster", a Mexican lizard. " Researchers found a molecule similar to insulin, but more stable," explains Sébastien Dutertre. This drug is now prescribed to thousands of diabetics to help reduce their blood sugar levels.
Not so harmless shellfish...
" Some twenty molecules derived from animal venoms are already on the market," explains Sébastien Dutertre. For the past 12 years, the biologist has been working on the venom of cone shells, magnificent tropical shells with colorful patterns that are very tempting to pick up as a vacation souvenir, but which turn out to be dangerous predators. " Some of them can even be fatal to humans, like the Conus geographus, which is the cause of numerous accidents ", warns the researcher. These gastropod molluscs have a kind of harpoon-shaped tooth called aradula, which they use to inject their powerful venom to attack their prey or defend themselves against predators. In 2004, the first drug derived from cone venom was marketed, Ziconotide.
It's a painkiller a thousand times more powerful than morphine," stresses Sébastien Dutertre, "and is particularly useful for patients who have become refractory to conventional opioids. This discovery has boosted research into cone venoms, which have revealed other particularly interesting properties. " The peptides in these venoms can preferentially target cancer cells, so they could be used as carrier molecules to develop targeted chemotherapies that don't kill healthy cells ", explains Sébastien Dutertre. Today, the researcher has turned his attention to a local species, the Languedoc scorpion.
The pharmacological properties of the molecules that make up its venom have not yet been studied ", explains Sébastien Dutertre. Perhaps this will pave the way for new medicines made in UM from the region...
Attack or defend, it all depends on the venom
Sébastien Dutertre and his colleagues have shown that cones do not use the same weapon to hunt as they do to defend themselves: they possess two completely different types of venom. This extraordinary ability has been identified for the first time. We've shown that cones only inject their deadly venom when threatened by a predator," explains Sébastien Dutertre. When it comes to feeding, they inject a less complex but highly effective venom that rapidly immobilizes their prey ". This unique property may be of interest to researchers, particularly in agrochemistry. " Cones feed in particular on small invertebrates such as worms, so we can imagine developing products from their predatory venom that could be used in agronomy to protect plants and crops from the attack of certain worms ".