From venom to medicine
Researchers at the Max Mousseron Biomolecules Institute (IBMM) are transforming poisons into medicines: they are sifting through animal venoms in search of new therapeutic molecules.
Snakes, scorpions, spiders, cone snails... 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 drugs. The idea of using animal venoms for medical purposes is not new; snake venom decoctions have been used in traditional Chinese medicine since ancient times. But systematic pharmacological research into these molecules is much more recent. "This field has only been developing intensively for about twenty years," explains Sébastien Dutertre, a researcher at the IBMM.
Poisons that heal
This research has led to the development of new drugs, some of which are now indispensable. Captopril, a drug now prescribed to thousands of patients suffering from high blood pressure, originates from the fangs of Bothrops jararaca, a formidable viper found in abundance in Brazil. The venom of this "lancehead viper" is deadly. Researchers discovered that it causes blood vessels to dilate, leading to a drop in blood pressure, a particularly interesting property for patients suffering from hypertension.
Another drug that sits prominently on our pharmacy shelves is Byetta, prescribed to patients with 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," says Sébastien Dutertre. This drug is now prescribed to thousands of diabetics to help them lower their blood sugar levels.
Shellfish that aren't so harmless...
"Around 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, beautiful tropical shells with colorful patterns that are very tempting to collect as vacation souvenirs, but which are actually dangerous predators. "Some of them can even be deadly to humans, such as the Conus geographus, which is responsible for many accidents," warns the researcher. These gastropod mollusks are equipped with a harpoon-like tooth calleda"radula"that allows them to inject their powerful venom to attack their prey or defend themselves against predators. In 2004, the first drug derived from cone snail venom, Ziconotide, was marketed.
" Itis a painkiller a thousand times more powerful than morphine," says Sébastien Dutertre, "and is particularly useful for patients who have become resistant to conventional opioids." This discovery has boosted research into cone snail venoms, which have revealed other particularly interesting properties. "The peptides in these venoms can preferentially target cancer cells, so they could be used as transport molecules to develop targeted chemotherapies that would not kill healthy cells," explains Sébastien Dutertre. Today, the researcher has turned his attention to a local species, the Languedoc scorpion.
This is certainly a closer research area, but also completely untouched: "The pharmacological properties of the molecules that make up its venom have not yet been studied," explains Sébastien Dutertre. Perhaps this is a path toward new UM-made drugs derived from the regional terroir...
Attack or defend, it all depends on the venom.
Sébastien Dutertre and his colleagues have shown that cone snails do not use the same weapon for hunting and defense: they have two completely different types of venom. This extraordinary ability has been identified for the first time. " We have demonstrated that cone snails only inject their deadly venom when threatened by a predator," explains Sébastien Dutertre. "When feeding, they inject a less complex but highly effective venom to quickly immobilize their prey." This unique property may be of interest to researchers, particularly in agrochemistry. "Cone snails feed mainly 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 attack by certain worms."