Contributed by Benjamin F. Cravatt, November 13, 2015 (sent for review October 23, 2015; reviewed by Christopher Fowler and Stephan Sieber)
Lipid transmitters, such as endocannabinoid and eicosanoids, play important roles in the nervous system and regulate behaviors that include pain, emotionality, and addiction. Chemical probes that perturb lipid transmitter biosynthesis are needed to understand the functions of these pathways in the nervous system. Here, we describe selective and in vivo active inhibitors of the diacylglycerol lipases DAGLα and DAGLβ, which biosynthesize the endocannabinoid 2-arachidonoylglycerol (2-AG). We show that these inhibitors produce rapid and dramatic changes in a brain lipid signaling network, comprising not only 2-AG, but also eicosanoids and diacylglycerols. These lipid changes are accompanied by impairments in synaptic plasticity and attenuation of neuroinflammatory responses in vivo, underscoring the broad role that DAGLs play in nervous system metabolism and function.
Diacylglycerol lipases (DAGLα and DAGLβ) convert diacylglycerol to the endocannabinoid 2-arachidonoylglycerol. Our understanding of DAGL function has been hindered by a lack of chemical probes that can perturb these enzymes in vivo. Here, we report a set of centrally active DAGL inhibitors and a structurally related control probe and their use, in combination with chemical proteomics and lipidomics, to determine the impact of acute DAGL blockade on brain lipid networks in mice. Within 2 h, DAGL inhibition produced a striking reorganization of bioactive lipids, including elevations in DAGs and reductions in endocannabinoids and eicosanoids. We also found that DAGLα is a short half-life protein, and the inactivation of DAGLs disrupts cannabinoid receptor-dependent synaptic plasticity and impairs neuroinflammatory responses, including lipopolysaccharide-induced anapyrexia. These findings illuminate the highly interconnected and dynamic nature of lipid signaling pathways in the brain and the central role that DAGL enzymes play in regulating this network.
↵1D.O. and H.D. contributed equally to this work.
This contribution is part of the special series of Inaugural Articles by members of the National Academy of Sciences elected in 2014.
Author contributions: D.O., H.D., A.V., H.S.O., B.C., Q.-s.L., and M.v.d.S. designed research; D.O., H.D., A.V., M.P.B., A.B., H.d.D., A.M.C.H.v.d.N., M.S., T.v.d.W., J.Z., M.S.-A., S.M., W.N., X.L., and Y.C. performed research; D.O., H.D., M.P.B., A.B., H.d.D., A.M.C.H.v.d.N., M.S., T.v.d.W., J.Z., M.S.-A., S.M., W.N., X.L., and Y.C. contributed new reagents/analytic tools; D.O., H.D., A.V., M.P.B., A.B., H.d.D., A.M.C.H.v.d.N., M.S., T.v.d.W., J.Z., H.S.O., M.S.-A., S.M., W.N., B.C., X.L., Y.C., Q.-s.L., B.F.C., and M.v.d.S. analyzed data; and D.O., H.D., A.V., H.d.D., H.S.O., B.C., Q.-s.L., B.F.C., and M.v.d.S. wrote the paper.
Reviewers: C.F., Umea University; and S.S., Technical University of Munich.
Conflict of interest statement: B.F.C. is a founder and advisor to Abide Therapeutics, a biotechnology company interested in developing serine hydrolase inhibitors as therapeutics.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1522364112/-/DCSupplemental.
