The endocannabinoids anandamide and 2-arachidonoylglycerol (2-AG) act through cannabinoid CB1 and CB2 receptors, and are inactivated by a two-step process: Both are transported into cells, and then anandamide is hydrolyzed by fatty acid amide hydrolase (FAAH) and 2-AG by monoacylglycerol lipase (MGL). Selective inhibition of either FAAH or MGL results in the accumulation of either anandamide or 2-AG, respectively, and in non-overlapping therapeutic effects. In a study funded by a NIDA-CEBRA grant, we found that the microglial cell line, BV-2, does not express MGL and yet efficiently hydrolyzes 2-AG, suggesting the existence of a new 2-AG-hydrolyzing enzyme that could be targeted for the treatment of pathologies associated with neuroinflammation. In collaboration with Ben Cravatt, we used a functional proteomics approach and identified ABHD6 as a candidate enzyme for 2-AG hydrolysis in BV-2 cells. More recently, we used shRNA knockdown and a newly developed ABHD6 inhibitor and showed that this enzyme plays a major role in 2-AG hydrolysis in both BV-2 cells and neurons. Because Hungtington's disease (HD) is associated with an early down-regulation of CB1 receptors and a chronic neuroinflammatory response, inhibiting ABHD6 might represent a valid therapeutic approach to treat this degenerative disease. In this grant proposal, we outline experiments designed to: 1) Map ABHD6 expression and activity in healthy and HD mice brains, 2) Determine the pharmacological profile of ABHD6 and develop novel inhibitors 3) Test if ABHD6 controls 2-AG signaling in microglia and neurons, and constitutes a valid target for treating HD mice. The completion of these three aims will provide a comprehensive understanding of the expression, activity and role of ABHD6 in microglia and neurons in healthy and degenerating brain. Our long-term goal is to generate pharmacological and genetic tools that selectively inhibit endocannabinoid inactivation as means to develop therapeutics that lack the abuse liability and adverse effects produced by cannabinoid agonists.

Public Health Relevance

In this grant proposal, we outline experiments designed to 1) Map the expression and activity of the novel endocannabinoid-hydrolyzing enzyme, ABHD6, in the brains of healthy mice, and of two mice models of Huntington's disease, 2) Determine the pharmacological profile and develop inhibitors of this novel enzyme and 3) Test its role in controlling endocannabinoid's ability to regulate microglial and neuronal cell functions, and whether its inhibition affects disease progression in a mouse model of Huntington's disease.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
1R01DA026430-01A1
Application #
7789781
Study Section
Molecular Neuropharmacology and Signaling Study Section (MNPS)
Program Officer
Rapaka, Rao
Project Start
2009-09-30
Project End
2014-08-31
Budget Start
2009-09-30
Budget End
2010-08-31
Support Year
1
Fiscal Year
2009
Total Cost
$351,000
Indirect Cost
Name
University of Washington
Department
Pharmacology
Type
Schools of Medicine
DUNS #
605799469
City
Seattle
State
WA
Country
United States
Zip Code
98195
Cao, Jessica K; Detloff, Peter J; Gardner, Richard G et al. (2018) Sex-dependent behavioral impairments in the HdhQ350/+ mouse line. Behav Brain Res 337:34-45
Grant, Kimberly S; Petroff, Rebekah; Isoherranen, Nina et al. (2018) Cannabis use during pregnancy: Pharmacokinetics and effects on child development. Pharmacol Ther 182:133-151
Kaplan, Joshua S; Stella, Nephi; Catterall, William A et al. (2017) Cannabidiol attenuates seizures and social deficits in a mouse model of Dravet syndrome. Proc Natl Acad Sci U S A 114:11229-11234
Deng, Liting; Ng, Lindsay; Ozawa, Tatsuya et al. (2017) Quantitative Analyses of Synergistic Responses between Cannabidiol and DNA-Damaging Agents on the Proliferation and Viability of Glioblastoma and Neural Progenitor Cells in Culture. J Pharmacol Exp Ther 360:215-224
Di Marzo, Vincenzo; Stella, Nephi; Zimmer, Andreas (2015) Endocannabinoid signalling and the deteriorating brain. Nat Rev Neurosci 16:30-42
Kow, Rebecca L; Cheng, Eugene M; Jiang, Kelly et al. (2015) Muscarinic M1 receptor and cannabinoid CB1 receptor do not modulate paraoxon-induced seizures. Pharmacol Res Perspect 3:e00100
Naydenov, Alipi V; Sepers, Marja D; Swinney, Katie et al. (2014) Genetic rescue of CB1 receptors on medium spiny neurons prevents loss of excitatory striatal synapses but not motor impairment in HD mice. Neurobiol Dis 71:140-50
Kow, Rebecca L; Jiang, Kelly; Naydenov, Alipi V et al. (2014) Modulation of pilocarpine-induced seizures by cannabinoid receptor 1. PLoS One 9:e95922
Cherry, A E; Stella, N (2014) G protein-coupled receptors as oncogenic signals in glioma: emerging therapeutic avenues. Neuroscience 278:222-36
Naydenov, Alipi V; Horne, Eric A; Cheah, Christine S et al. (2014) ABHD6 blockade exerts antiepileptic activity in PTZ-induced seizures and in spontaneous seizures in R6/2 mice. Neuron 83:361-371

Showing the most recent 10 out of 20 publications