Document Type
Article
Publication Date
12-1-2008
Description
Macrophage apoptosis is an important process in the pathophysiology of atherosclerosis. Oxidized low-density lipoproteins (OxLDL) are a major component of lesions and potently induce macrophage apoptosis. Cannabinoid receptor 2 (CB2), the predominant macrophage cannabinoid receptor, modulates several macrophage processes associated with ongoing atherosclerosis; however, the role of CB2 in macrophage apoptosis is unknown. To determine if CB2 influences a macrophage apoptotic pathway relevant to atherosclerosis, we examined the effect of CB2 deficiency on OxLDL-induced macrophage apoptosis. In situ terminal transferase-mediated dUTP nick end labeling (TUNEL) analysis of resident peritoneal macrophages detected significantly fewer apoptotic CB2-/- macrophages than CB2+/+ macrophages after incubation with OxLDL (27.9 ± 4.7% vs. 61.9 ± 8.5%, P < 0.001) or 7-ketocholesterol (7KC) (18.9 ± 10.5% vs. 54.1 ± 6.9%, P < 0.001), an oxysterol component of OxLDL. Caspase-3 activity; proteolytic conversion of procaspase-3; and cleavage of a caspase-3 substrate, PARP, were also diminished in 7KC-treated CB2-/-macrophages. Furthermore, the deactivation of the prosurvival kinase, Akt, in response to 7KC was impaired in CB2-/-macrophages. These results suggest that CB2 expression increases the susceptibility of macrophages to OxLDL-induced apoptosis, in part, by modulating the effect of oxysterols on the Akt survival pathway and that CB2 may influence atherosclerosis by modulating lesional macrophage apoptosis.
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Citation Information
Freeman-Anderson, Natalie; Pickle, Theresa G.; Netherland, Courtney D.; Bales, Alicia; Buckley, Nancy E.; and Thewke, Douglas P.. 2008. Cannabinoid (CB2) Receptor Deficiency Reduces the Susceptibility of Macrophages to Oxidized LDL/Oxysterol-Induced Apoptosis. Journal of Lipid Research. Vol.49(11). 2338-2346. https://doi.org/10.1194/jlr.M800105-JLR200 PMID: 18614816 ISSN: 0022-2275
Copyright Statement
© 2008 ASBMB. Currently published by Elsevier Inc; originally published by American Society for Biochemistry and Molecular Biology.
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