A novel fluorophosphonate inhibitor of the biosynthesis of the endocannabinoid 2-arachidonoylglycerol with potential anti-obesity effects

BACKGROUND.: The development of potent and selective inhibitors of the biosynthesis of the endocannabinoid 2-AG via diacylglycerol lipases (DAGL) ? and ? is just starting to be considered as a novel and promising source of pharmaceuticals for the treatment of disorders that might benefit from a reduction of endocannabinoid tone, such as hyperphagia in obese subjects. METHODS.: Three new fluorophosphonate compounds: 1-((fluoro(methyl)phosphoryl)oxy)-3-(penthyloxy)propan-2-yl oleate (O-7458); 1-ethoxy-3-((fluoro(methyl)phosphoryl)oxy)propan-2-yl oleate (O-7459); and 1-((fluoro(methyl)phosphoryl)oxy)-3-isopropoxypropan-2-yl oleate (O-7460) were synthesized and characterized in various enzymatic assays. O-7460 was tested on high fat diet intake in mice. RESULTS.: Of the new compounds, O-7460 exhibited the highest potency (IC(50) =690 nM) against the human recombinant DAGL?, and selectivity (IC(50) >10 ?M) towards COS-7 cell and human monoacylglycerol lipase (MAGL), and rat brain fatty acid amide hydrolase (FAAH). Competitive activity-based protein profiling confirmed that O-7460 inhibits mouse brain MAGL only at concentrations > 10 ?M, and showed that this compound has only one major "off-target", i.e. the serine hydrolase KIAA1363. O-7460 did not exhibit measurable affinity for human recombinant CB(1) or CB(2) cannabinoid receptors (K(i) >10 ?M). In mouse neuroblastoma N18TG2 cells stimulated with ionomycin, O-7460 (10 ?M) reduced 2-AG levels. When administered to mice, O-7460 dose-dependently (0-12 mg/kg, i.p.) inhibited the intake of a high fat diet over a 14 h observation period, and, subsequently, slightly but significantly reduced body weight. CONCLUSIONS.: O-7460 might be considered a useful pharmacological tool to investigate further the role played by 2-AG both in vitro and in vivo under physiological as well as pathological conditions.