San Diego, November 15, 2016
Monoacylglycerol lipase (MGLL) is a serine hydrolase enzyme that converts monoacylglycerols into fatty acids and glycerol. The MGLL substrate 2-arachidonoylglycerol (2-AG) is an endogenous ligand of the cannabinoid receptors CB1 and CB2, which are the molecular targets of the psychoactive component of Cannabis sativa, Δ9tetrahydrocannabinol (THC). Inhibition or genetic inactivation of MGLL results in accumulation of 2-AG in the brain and periphery and CB1/2-dependent anti-nociceptive and anti-inflammatory effects. Additionally, MGLL inactivation in mice reduces levels of arachidonic acid (AA) and pro-inflammatory prostanoid metabolites in a subset of tissues including the brain, liver and lung. MGLL inhibition may therefore provide therapeutic benefit via enhancing cannabinoid receptor signaling and reducing prostanoid signaling.
To further evaluate the therapeutic potential of MGLL inhibition, we have developed ABD-1970, a potent and selective MGLL inhibitor. ABD-1970 is a hexafluoroisopropyl carbamate that covalently inhibits MGLL in vitro with IC50 values of <50 nM across species. The selectivity of ABD-1970 for MGLL amongst other serine hydrolases has been extensively profiled using gel- and mass spectrometry-based activity-based protein profiling (ABPP) technologies.
ABD-1970 has been used to explore the effects of MGLL inhibition in human systems in vitro. We determined that MGLL is expressed and active in many regions of the post-mortem human brain. Homogenates prepared from human brain cortex readily hydrolyze 2-AG and we confirmed that this activity is largely mediated by MGLL by its sensitivity to ABD-1970 treatment.
Though MGLL inhibition has been shown to reduce prostanoid production in mice, the effects of MGLL inhibition on prostanoid production and signaling in human systems is not well understood. Cyclooxygenase (COX) inhibitors, such as non-steroidal anti-inflammatory drugs (NSAIDs), dramatically reduce prostanoid production in humans and carry both therapeutically beneficial effects as well as gastro-intestinal and cardiovascular side-effects. To compare the effects of MGLL and COX inhibition in human cells, ABD-1970 and the NSAID indomethacin were tested in three paradigms: 1) prostanoid production in stimulated human whole blood, 2) prostanoid production in stimulated human endothelial cells and 3) collagen-induced platelet aggregation. The results of these assays clearly differentiated MGLL inhibition from COX
inhibition as ABD-1970 was without effect in all three assays whereas indomethacin produced robust suppression of prostanoid production and platelet aggregation.