cannabidiol and arachidonyl-2-chloroethylamide

Autophagy is a catabolic process involved in homeostatic and regulated cellular protein recycling and degradation via the lysosomal degradation pathway. Emerging data associate impaired autophagy, increased activity in the endocannabinoid system, and upregulation of suppressor of cytokine signaling-3 (SOCS3) protein expression during intestinal inflammation. We have investigated whether these three processes are linked. By assessing the impact of the phytocannabinoid cannabidiol (CBD), the synthetic cannabinoid arachidonyl-2'-chloroethylamide (ACEA), and the endocannabinoid N-arachidonoylethanolamine (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 Caco-2 cells, a model of mature intestinal epithelium. ACEA and AEA induced canonical autophagy, which was cannabinoid type 1 receptor-mediated. In contrast, CBD was able to bypass the cannabinoid type 1 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 early and late autophagy. In conclusion, the regulatory protein SOCS3 is regulated by autophagy, and cannabinoids play a role in this process, which could be important when therapeutic applications for the cannabinoids in inflammatory conditions are considered.

Topics: Arachidonic Acids; Autophagy; Blotting, Western; Caco-2 Cells; Cannabidiol; Cannabinoid Receptor Agonists; Cannabinoids; Dose-Response Relationship, Drug; Down-Regulation; Endocannabinoids; Humans; Intestinal Mucosa; Microscopy, Confocal; Polyunsaturated Alkamides; Receptor, Cannabinoid, CB1; RNA Interference; Signal Transduction; Suppressor of Cytokine Signaling 3 Protein; Suppressor of Cytokine Signaling Proteins; Time Factors; Transfection

The neuroprotective potential of cannabinoids has been examined in rats with striatal lesions caused by 3-nitropropionic acic (3NP), an inhibitor of mitochondrial complex II. We used the CB1 agonist arachidonyl-2-chloroethylamide (ACEA), the CB2 agonist HU-308, and cannabidiol (CBD), an antioxidant phytocannabinoid with negligible affinity for cannabinoid receptors. The administration of 3NP reduced GABA contents and also mRNA levels for several markers of striatal GABAergic projection neurons, including proenkephalin (PENK), substance P (SP) and neuronal-specific enolase (NSE). We also found reductions in mRNA levels for superoxide dismutase-1 (SOD-1) and -2 (SOD-2), which indicated that 3NP reduced the endogenous antioxidant defences. The administration of CBD, but not ACEA or HU-308, completely reversed 3NP-induced reductions in GABA contents and mRNA levels for SP, NSE and SOD-2, and partially attenuated those found in SOD-1 and PENK. This indicates that CBD is neuroprotective but acted preferentially on striatal neurons that project to the substantia nigra. The effects of CBD were not reversed by the CB1 receptor antagonist SR141716. The same happened with the TRPV1 receptor antagonist capsazepine, in concordance with the observation that capsaicin, a TRPV1 receptor agonist, failed to reproduce the CBD effects. The effects of CBD were also independent of adenosine signalling as they were not attenuated by the adenosine A2A receptor antagonist MSX-3. In summary, this study demonstrates that CBD provides neuroprotection against 3NP-induced striatal damage, which may be relevant for Huntington's disease, a disorder characterized by the preferential loss of striatal projection neurons. This capability seems to be based exclusively on the antioxidant properties of CBD.

Topics: Adenosine A2 Receptor Agonists; Animals; Arachidonic Acids; Atrophy; Brain Chemistry; Cannabidiol; Cannabinoid Receptor Agonists; Cannabinoids; Chromatography, High Pressure Liquid; Convulsants; Dopamine; gamma-Aminobutyric Acid; Glutamic Acid; In Situ Hybridization; Male; Neostriatum; Nitro Compounds; Phosphopyruvate Hydratase; Propionates; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; RNA, Messenger; TRPV Cation Channels