Contrasting protective effects of cannabinoids against oxidative stress and amyloid-β evoked neurotoxicity in vitro

• Published in: Neurotoxicology (Park Forest South) Vol. 33; no. 1; pp. 138 - 146
• Main Authors: Harvey, Benjamin S., Ohlsson, Katharina S., Mååg, Jesper L.V., Musgrave, Ian F., Smid, Scott D.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-01-2012; Elsevier
• Subjects: Amyloid beta-Peptides - metabolism; Amyloid beta-Peptides - pharmacology; Amyloid beta-Peptides - ultrastructure; Analysis of Variance; Animals; Antioxidants - pharmacology; Arachidonic Acids - pharmacology; Biological and medical sciences; Cannabinoid; Cannabinoids - pharmacology; Cell Line, Tumor; Cell Survival - drug effects; Chromans - pharmacology; Drug addictions; Drug Interactions; Gene Expression Regulation - drug effects; Humans; Hydrogen Peroxide - pharmacology; Indoles - pharmacology; Lipid Peroxidation - drug effects; Medical sciences; Microscopy, Electron, Transmission; Neuroblastoma - pathology; Neuroprotection; Neurosciences; Neurovetenskaper; Oxidative stress; Oxidative Stress - drug effects; PC12 Cells - drug effects; Peptide Fragments - pharmacology; Rats; Receptor, Cannabinoid, CB1 - agonists; Receptor, Cannabinoid, CB1 - genetics; Receptor, Cannabinoid, CB1 - metabolism; Receptor, Cannabinoid, CB2 - genetics; Receptor, Cannabinoid, CB2 - metabolism; Thiazoles; Toxicology; β-Amyloid; β-Amyloid; Neuroprotection; Oxidative stress; Cannabinoid; Prevention; Neurotoxicity; Nervous system diseases; Toxicity; Protective factor; Amyloid; Drug of abuse; In vitro
• ISSN: 0161-813X; 1872-9711; 1872-9711
• DOI: 10.1016/j.neuro.2011.12.015

► Alzheimer's protein amyloid-β and pro-oxidants elicit neurotoxicity in vitro. ► We compared neuroprotective effects of cannabinoid ligands against these stressors. ► Cannabidiol variably protects against pro-oxidant evoked neurotoxicity. ► Anandamide but not cannabidiol protects against amyloid-β neurotoxicity. ► Cannabinoid ligands did not disrupt preformed amyloid-β fibrils and aggregates.
Cannabinoids have been widely reported to have neuroprotective properties in vitro and in vivo. In this study we compared the effects of CB1 and CB2 receptor-selective ligands, the endocannabinoid anandamide and the phytocannabinoid cannabidiol, against oxidative stress and the toxic hallmark Alzheimer's protein, β-amyloid (Aβ) in neuronal cell lines. PC12 or SH-SY5Y cells were selectively exposed to either hydrogen peroxide, tert-butyl hydroperoxide or Aβ, alone or in the presence of the CB1 specific agonist arachidonyl-2′-chloroethylamide (ACEA), CB2 specific agonist JWH-015, anandamide or cannabidiol. Cannabidiol improved cell viability in response to tert-butyl hydroperoxide in PC12 and SH-SY5Y cells, while hydrogen peroxide-mediated toxicity was unaffected by cannabidiol pretreatment. Aβ exposure evoked a loss of cell viability in PC12 cells. Of the cannabinoids tested, only anandamide was able to inhibit Aβ-evoked neurotoxicity. ACEA had no effect on Aβ-evoked neurotoxicity, suggesting a CB1 receptor-independent effect of anandamide. JWH-015 pretreatment was also without protective influence on PC12 cells from either pro-oxidant or Aβ exposure. None of the cannabinoids directly inhibited or disrupted preformed Aβ fibrils and aggregates. In conclusion, the endocannabinoid anandamide protects neuronal cells from Aβ exposure via a pathway unrelated to CB1 or CB2 receptor activation. The protective effect of cannabidiol against oxidative stress does not confer protection against Aβ exposure, suggesting divergent pathways for neuroprotection of these two cannabinoids.