Cannabis is the most common illicit drug of abuse in the US and globally. In addition, many states in the US, as well as several countries in the world, have legalized the medical and/or recreational use of cannabis. In this rapidly expanding landscape of cannabis use, huge efforts are made to find innovative interventions reducing potential cannabis-evoked harms. Here, we investigated the possible relation between cannabinoids and autophagy, the process of programmed cell “self-digestion”, and asked whether it could be related to the control of motor coordination behavior, one of the best established neurobiological processes impacted by cannabinoids.
We showed that Δ9-tetrahydrocannabinol, the major psychoactive ingredient of cannabis, impairs autophagy and accumulates P62 protein in neurons of the striatum, a brain area that plays a key role in the control of motor coordination. Second, we demonstrate that boosting autophagy, either by pharmacological manipulation (with the FDA-approved mammalian target of rapamycin inhibitor temsirolimus) or by dietary intervention (with the natural, non-toxic disaccharide trehalose), rescues the Δ9-tetrahydrocannabinol-induced impairment of striatal autophagy and motor coordination in mice. Furthermore, we provide evidence that cannabinoid CB1 receptors located on neurons of the striatal direct (stratonigral) pathway, by coupling to mammalian target of rapamycin activation and autophagy inhibition, are indispensable for the motor dyscoordinating activity of Δ9-tetrahydrocannabinol in mice.
Last but not least, using viral mediated genetic manipulation of striatonigral neurons we confirmed that disrupting mammalian target of rapamycin pathway, as well as boosting P62 accumulation in these cells, completely prevents Δ9-tetrahydrocannabinol-induced impairment of striatal autophagy and motor dyscoordination in mice.
Taken together, these findings identify impairment of autophagy as an unprecedented mechanistic link between cannabinoids and motor dyscoordination, and suggest that activators of autophagy might be considered as promising therapeutic tools to treat certain cannabinoid-evoked behavioral alterations.
Inhibition of striatonigral autophagy as a link between cannabinoid intoxication and impairment of motor coordination. Cristina Blázquez, Andrea Ruiz-Calvo, Raquel Bajo-Grañeras, Jérôme M Baufreton, Eva Resel, Marjorie Varilh, Antonio C Pagano Zottola, Yamuna Mariani, Astrid Cannich, José A Rodríguez-Navarro, Giovanni Marsicano, Ismael Galve-Roperh, Luigi Bellocchio, Manuel Guzmán ; eLife 2020;9:e56811doi: 10.7554/eLife.56811