Endocannabinoid hydrolysis inhibition unmasks that unsaturated fatty acids induce a robust biosynthesis of 2‐arachidonoyl‐glycerol and its congeners in human myeloid leukocytes

Abstract

The endocannabinoid (eCB) 2‐arachidonoyl‐gycerol (2‐AG) modulates immune responses by activating cannabinoid receptors or through its multiple metabolites, notably eicosanoids. Thus, 2‐AG hydrolysis inhibition might represent an interesting anti‐inflammatory strategy that would simultaneously increase the levels of 2‐AG and decrease those of eicosanoids. Accordingly, 2‐AG hydrolysis inhibition increased 2‐AG half‐life in neutrophils. Under such setting, neutrophils, eosinophils, and monocytes synthesized large amounts of 2‐AG and other monoacylglycerols (MAGs) in response to arachidonic acid (AA) and other unsaturated fatty acids (UFAs). Arachidonic acid and UFAs were ~1000‐fold more potent than G protein‐coupled receptor (GPCR) agonists. Triascin C and thimerosal, which, respectively, inhibit fatty acyl‐CoA synthases and acyl‐CoA transferases, prevented the UFA‐induced MAG biosynthesis, implying glycerolipid remodeling. 2‐AG and other MAG biosynthesis was preceded by that of the corresponding lysophosphatidic acid (LPA). However, we could not directly implicate LPA dephosphorylation in MAG biosynthesis. While GPCR agonists poorly induced 2‐AG biosynthesis, they inhibited that induced by AA by 25%‐50%, suggesting that 2‐AG biosynthesis is decreased when leukocytes are surrounded by a pro‐inflammatory entourage. Our data strongly indicate that human leukocytes use AA and UFAs to biosynthesize biologically significant concentrations of 2‐AG and other MAGs and that hijacking the immune system with 2‐AG hydrolysis inhibitors might diminish inflammation in humans.

Dietary fatty acid intake and gut microbiota determine circulating endocannabinoidome signaling beyond the effect of body fat

“…Levels of NAEs and 2‑MAGs in plasma samples (200 uL) were measured using high-performance liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) as previously described 34 . It allows the quantification of NAEs including AEA, N -palmitoyl‑ethanolamine (PEA), N -oleoyl‑ethanolamine (OEA), N -linoleoyl-ethanolamine (LEA), N -docosapentaenoyl‑ethanolamine (DPEA), N -eicosapentaenoyl-ethanolamine (EPEA) and N -docosahexaenoyl‑ethanolamine (DHEA), as well as 2-MAG including 2-AG, 2-palmitoyl-glycerol (2-PG), 2-oleoyl-glycerol (2‑OG), 2-linoleoyl-glycerol (2-LG), 2-eicosapenaenoyl-glycerol (2-EPG), 2-docosapentaenoyl‑glycerol (2-DPG) and 2­docosahexaenoyl-glycerol (2‑DHG).…”

Emerging Role of Phospholipase-Derived Cleavage Products in Regulating Eosinophil Activity: Focus on Lysophospholipids, Polyunsaturated Fatty Acids and Eicosanoids

“…In contrast to soluble IP 3 , DAG remains bound at the cell membrane, where diacylglycerol lipase may hydrolyze it to 2-arachidonolyglycerol (2-AG) [ 248 ]. Eosinophils were recently discovered to express high levels of DAG lipase in contrast to neutrophils and lymphocytes, indicating the importance of the pathway for 2-AG synthesis in these cells [ 249 ].…”

Role of the Endocannabinoid System in the Adipose Tissue with Focus on Energy Metabolism

“…As with AEA, 2-AG biosynthesis can occur via numerous biosynthetic pathways. In many cell types, 2-AG arises from the sequential actions of phospholipase C and 1,2-diacylglycerol (DAG) lipases [ 40 ], although an alternative and more efficient biosynthetic route exists in human leukocytes and involves the acylation of free FAs into cellular membranes, followed by a subsequent release of 2-AG with a possible LPA intermediate [ 45 ]. 2-AG is hydrolyzed by at least seven enzymes [ 46 , 47 ] although the most recognized one for this function is the monoacylglycerol (MAG) lipase [ 48 ].…”