Cannabinoid-induced autophagy regulates suppressor of cytokine signaling (SOCS)-3 in intestinal epithelium

Koay, Luan and Rigby, Rachael and Wright, Karen (2014) Cannabinoid-induced autophagy regulates suppressor of cytokine signaling (SOCS)-3 in intestinal epithelium. American Journal of Physiology-Gastrointestinal and Liver Physiology, 307. G140-G148. ISSN 0193-1857

Abstract

Autophagy is a catabolic process involved in homeostatic and regulated cellular protein recycling and degradation via the lysosomal degradation pathway. Emerging data associates impaired autophagy, increased activity in the endocannabinoid system and upregulation of suppressor of cytokine signaling (SOCS)-3 protein expression during intestinal inflammatory states. We have investigated whether these three processes are linked. By assessing the impact of phyto-cannabinoid cannabidiol (CBD), synthetic cannabinoid (ACEA) and endocannabinoid (AEA) on autophagosome formation, we explored whether these actions were responsible for cyclic SOCS3 protein levels. Our findings show that all three cannabinoids induce autophagy in a dose-dependent manner in fully differentiated CaCo2 cells, a model of mature intestinal epithelium. ACEA and AEA induced canonical autophagy, which was cannabinoid receptor (CB)-1 mediated. In contrast, CBD was able to bypass both the CB1 receptor and the canonical pathway to induce autophagy, albeit to a lesser extent. Functionally, all three cannabinoids reduced SOCS3 protein expression, which was reversed by blocking both early and late autophagy. In conclusion, the regulatory protein, SOCS3, is itself regulated by autophagy and cannabinoids play a role in this process, which could be important when considering therapeutic applications for the cannabinoids in inflammatory conditions.