Cannabinoid-1 receptor activation induces reactive oxygen species-dependent and -independent mitogen-activated protein kinase activation and cell death in human coronary artery endothelial cells

Cannabinoid 1 receptor activation contributes to vascular inflammation and cell death in a mouse model of diabetic retinopathy and a human retinal cell line

AIMS/HYPOTHESIS

Recent studies have demonstrated that cannabinoid-1 (CB(1)) receptor blockade ameliorated inflammation, endothelial and/or cardiac dysfunction, and cell death in models of nephropathy, atherosclerosis and cardiomyopathy. However the role of CB(1) receptor signalling in diabetic retinopathy remains unexplored. Using genetic deletion or pharmacological inhibition of the CB(1) receptor with SR141716 (rimonabant) in a rodent model of diabetic retinopathy or in human primary retinal endothelial cells (HREC) exposed to high glucose, we explored the role of CB(1) receptors in the pathogenesis of diabetic retinopathy.

METHODS

Diabetes was induced using streptozotocin in C57BL/6J Cb(1) (also known as Cnr1)(+/+) and Cb(1)(-/-) mice aged 8 to 12 weeks. Samples from mice retina or HREC were used to determine: (1) apoptosis; (2) activity of nuclear factor kappa B, intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), poly (ADP-ribose) polymerase and caspase-3; (3) content of 3-nitrotyrosine and reactive oxygen species; and (4) activation of p38/Jun N-terminal kinase/mitogen-activated protein kinase (MAPK).

RESULTS

Deletion of CB(1) receptor or treatment of diabetic mice with CB(1) receptor antagonist SR141716 prevented retinal cell death. Treatment of diabetic mice or HREC cells exposed to high glucose with SR141716 attenuated the oxidative and nitrative stress, and reduced levels of nuclear factor κB, ICAM-1 and VCAM-1. In addition, SR141716 attenuated the diabetes- or high glucose-induced pro-apoptotic activation of MAPK and retinal vascular cell death.

CONCLUSIONS/INTERPRETATION

Activation of CB(1) receptors may play an important role in the pathogenesis of diabetic retinopathy by facilitating MAPK activation, oxidative stress and inflammatory signalling. Conversely, CB(1) receptor inhibition may be beneficial in the treatment of this devastating complication of diabetes.

Fatty acid amide hydrolase is a key regulator of endocannabinoid-induced myocardial tissue injury

Previous studies have suggested that increased levels of endocannabinoids in various cardiovascular disorders (e.g., various forms of shock, cardiomyopathies, atherosclerosis) through the activation of CB(1) cannabinoid receptors may promote cardiovascular dysfunction and tissue injury. We have investigated the role of the main endocannabinoid anandamide-metabolizing enzyme (fatty acid amide hydrolase; FAAH) in myocardial injury induced by an important chemotherapeutic drug, doxorubicin (DOX; known for its cardiotoxicity mediated by increased reactive oxygen and nitrogen species generation), using well-established acute and chronic cardiomyopathy models in mice. The DOX-induced myocardial oxidative/nitrative stress (increased 4-hydroxynonenal, protein carbonyl, and nitrotyrosine levels and decreased glutathione content) correlated with multiple cell death markers, which were enhanced in FAAH knockout mice exhibiting significantly increased DOX-induced mortality and cardiac dysfunction compared to their wild type. The effects of DOX in FAAH knockouts were attenuated by CB(1) receptor antagonists. Furthermore, anandamide induced enhanced cell death in human cardiomyocytes pretreated with FAAH inhibitor and enhanced sensitivity to ROS generation in inflammatory cells of FAAH knockouts. These results suggest that in pathological conditions associated with acute oxidative/nitrative stress FAAH plays a key role in controlling the tissue injury that is, at least in part, mediated by the activation of CB(1) receptors by endocannabinoids.

CADgene: a comprehensive database for coronary artery disease genes

Coronary artery disease (CAD) is a complex, multifactorial disease and a leading cause of mortality world wide. Over the past decades, great efforts have been made to elucidate the underlying genetic basis of CAD and massive data have been accumulated. To integrate these data together and to provide a useful resource for researchers, we developed the CADgene, a comprehensive database for CAD genes. We manually extracted CAD-related evidence for more than 300 candidate genes for CAD from over 1300 publications of genetic studies. We classified these candidate genes into 12 functional categories based on their roles in CAD. For each gene, we extracted detailed information from related studies (e.g. the size of case–control, population, SNP, odds ratio, P-value, etc.) and made useful annotations, which include general gene information, Gene Ontology annotations, KEGG pathways, protein–protein interactions and others. Besides the statistical number of studies for each gene, CADgene also provides tools to search and show the most frequently studied candidate genes. In addition, CADgene provides cumulative data from 11 publications of CAD-related genome-wide association studies. CADgene has a user-friendly web interface with multiple browse and search functions. It is freely available at http://www.bioguo.org/CADgene/.