​Autophagy is a natural cell self-cleaning process inherited from evolution. It is a complex and highly regulated degradation mechanism that enables cells to survive in response to various types of stress, as well as intracellular pathogens. Numerous studies have shown that intoxication by bacterial toxins induces protective autophagy responses. This is the case for Bacillus anthracis toxin, anthrax, Clostridium difficile toxin B and E.coli Shigatoxin 2.

Ricin is a plant toxin produced by the castor bean that inhibits cell protein synthesis, resulting in cell death. There is currently no approved treatment for patients exposed to this toxin, classified as a biothreat agent. Ricin-induced apoptosis (programmed cell death) has been extensively studied, but the question of whether ricin intoxication also solicits autophagic processes remains unresolved.

In this study, researchers demonstrated that ricin intoxication is accompanied by its own autophagic degradation in mammalian cells. In fact, they show that induction of autophagy partially protects the cells, and that the quantity of ricin in the cell decreases.

The results indicate that a protective autophagy process is indeed triggered during ricin poisoning, and that stimulating this degradation pathway could help counteract this deadly cellular intoxication.

Contact : Julien Barbier (julien.barbier@cea.fr )