In line with the ESC mission, newly presented content is made available to all for a limited time (4 months for ESC Congress, 3 months for other events). ESC Professional Members, Association Members (Ivory & above) benefit from year-round access to all the resources from their respective Association, and to all content from previous years. Fellows of the ESC (FESC), and Professionals in training or under 40 years old, who subscribed to a Young Combined Membership package benefit from access to all ESC 365 content from all events, all editions, all year long. Find out more about ESC Memberships here.
2-arachidonoylglycerol activates pro-inflammatory pathways in murine macrophages and promotes atherogenesis in ApoE-/- mice
Authors : J Jehle (Bonn,DE), B Schoene (Bonn,DE), S Bagheri (Bonn,DE), E Avraamidou (Bonn,DE), M Danisch (Bonn,DE), A Franz (Bonn,DE), P Pfeifer (Bonn,DE), L Bindila (Mainz,DE), B Lutz (Mainz,DE), D Luetjohann (Bonn,DE), A Zimmer (Bonn,DE), G Nickenig (Bonn,DE)
J. Jehle1
,
B. Schoene1
,
S. Bagheri1
,
E. Avraamidou1
,
M. Danisch1
,
A. Franz1
,
P. Pfeifer1
,
L. Bindila2
,
B. Lutz2
,
D. Luetjohann3
,
A. Zimmer3
,
G. Nickenig1
,
1University Hospital Bonn, Department of Cardiology - Bonn - Germany
,
2Johannes Gutenberg University Mainz (JGU) - Mainz - Germany
,
3University Hospital Bonn - Bonn - Germany
,
Background: The endocannabinoid (eCB) 2-arachidonoylglycerol (2-AG) is a known modulator of inflammation and ligand to both, pro-inflammatory cannabinoid receptor 1 (CB1) and anti-inflammatory CB2. While the role of both cannabinoid receptors in atherogenesis has been studied extensively, the influence of 2-AG on atherogenesis and the underlying molecular mechanisms are still unclear.
Methods: The impact of 2-AG on atherogenesis was studied in two treatment groups of ApoE-/- mice. One group received the monoacylglycerol lipase (MAGL)-inhibitor JZL184 [5 mg/kg i.p.], which impairs 2-AG degradation and thus causes elevated 2-AG levels, the other group received vehicle for 4 weeks. Simultaneously, both groups were fed a high-cholesterol diet. The atherosclerotic plaque burden was assessed following oil red O staining and infiltrating macrophages were detected by immunofluorescence targeting CD68. In vitro, the effect of 2-AG on macrophage migration was assessed by Boyden chamber experiments. The impact of 2-AG on adhesion molecules, chemokine receptors and cholesterol metabolism was assessed by qPCR in immortalized macrophages.
Results: Application of the MAGL-inhibitor JZL184 resulted in a significant increase in 2-AG levels in vascular tissue (98.2±16.1 nmol/g vs. 27.3±4.5 nmol/g; n=14–16; p<0.001) without affecting levels of other eCBs or arachidonic acid. ApoE-/- mice with elevated 2-AG levels displayed a significantly increased plaque burden compared to vehicle treated controls (0.46±0.03 vs. 0.36±0.03; n=11–12; p=0.0391) and increased numbers of infiltrating macrophages within the atherosclerotic vessel wall (0.32±0.02 vs. 0.26±0.01; n=11; p=0.0244). While there was no alteration to the white blood counts of JZL184-treated animals, 2-AG enhanced macrophage migration in vitro by 1.8±0.2 -fold (n=4–6; p=0.0393) compared to vehicle which was completely abolished by co-administration of either CB1- or CB2-receptor-antagonists. qPCR analyses of 2-AG-stimulated macrophages showed an enhanced transcription of the chemokine CCL5 (1.59±0.23-fold; n=5–6; p=0.0589) and its corresponding receptors CCR1 (2.04±0.46-fold; n=10–11; p=0.0472) and CCR5 (2.45±0.62 –fold; n=5–6; p=0.0554). Additionally, transcription of intercellular adhesion molecule ICAM-1 was significantly increased by 2-AG (2.09±0.42 –fold; n=5–6; p=0.0447). Lastly, 2-AG increased mRNA levels of scavenging receptor CD36 which is known to promote oxLDL uptake into macrophages (8.02±1.89 –fold; n=3; p=0.0279), without affecting transcription of the cholesterol efflux transporters.
Conclusion: Taken together, elevated 2-AG levels appear to promote atherogenesis in vivo. Our data suggest that 2-AG promotes macrophage migration and might increase oxLDL accumulation in macrophages. Thus, decreasing vascular 2-AG levels might represent a novel therapeutic strategy in patients suffering from atherosclerosis and coronary heart disease.