Erratum to “The potency of the fatty acid amide hydrolase inhibitor URB597 is dependent upon the assay pH”[Pharmacol. Res. 54 (2006) 481–485] (original) (raw)
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The potency of the fatty acid amide hydrolase inhibitor URB597 is dependent upon the assay pH
Pharmacological research, 2006
Inhibitors of the enzyme fatty acid amide hydrolase (FAAH), the principal enzyme involved in the metabolism of the endogenous cannabinoid anandamide, have potential utility in the treatment of disorders including inflammation and inflammatory pain. The carbamate compound URB597 (3 -carbamoyl-biphenyl-3-yl-cyclohexylcarbamate) potently and selectively inhibits FAAH by forming a covalent bond with a key serine residue of the enzyme. Little is known as to the pH dependency of this inhibition. Using a preincubation time of 10 min, URB597 inhibited rat brain anandamide hydrolysis with pI 50 values of 7.19 ± 0.02 and 7.75 ± 0.06 at pH 6 and 8, respectively. The inhibition was time-dependent, and second order rate constants of ∼0.15 × 10 6 M −1 min −1 (pH 6) and ∼1.2 × 10 6 M −1 min −1 (pH 8) could be estimated. In intact C6 glioma cells and using a preincubation time of 10 min, URB597 inhibited the hydrolysis of 250 nM [ 3 H]AEA hydrolysis with pI 50 values of 5.58 ± 0.07 and 6.45 ± 0.07 at extracellular pH values of 6 and 8, respectively. Since tissue pH is affected by inflammation, these data would suggest that the pH selectivity of the inhibition can contribute to the potency of the compound in vivo.
Journal of Pharmacology and Experimental Therapeutics, 2004
Fatty acid amide hydrolase (FAAH) is an intracellular serine enzyme that catalyzes the hydrolysis of bioactive fatty acid ethanolamides such as anandamide and oleoylethanolamide (OEA). Genetic deletion of the faah gene in mice elevates brain anandamide levels and amplifies the effects of this endogenous cannabinoid agonist. Here, we show that systemic administration of the selective FAAH inhibitor URB597 (cyclohexyl carbamic acid 3Ј-carbamoyl-biphenyl-3-yl ester; 0.3 mg/kg i.p.) increases anandamide levels in the brain of rats and wild-type mice but has no such effect in FAAH-null mutants. Moreover, URB597 enhances the hypothermic actions of anandamide (5 mg/kg i.p.) in wild-type mice but not in FAAH-null mice. In contrast, the FAAH inhibitor does not affect anandamide or OEA levels in the rat duodenum at doses that completely inhibit FAAH activity. In addition, URB597 does not alter the hypophagic response elicited by OEA (5 and 10 mg/kg i.p.), which is mediated by activation of peroxisome proliferator-activated receptor type-␣. Finally, exogenously administered OEA (5 mg/kg i.p.) was eliminated at comparable rates in wild-type and FAAH Ϫ/Ϫ mice. Our results indicate that URB597 increases brain anandamide levels and magnifies anandamide responses by inhibiting intracellular FAAH activity. The results also suggest that an enzyme distinct from FAAH catalyzes OEA hydrolysis in the duodenum, where this lipid substance acts as a local satiety factor. ABBREVIATIONS: OEA, oleoylethanolamide; PEA, palmitoylethanolamide; FAE, fatty acid ethanolamide; FAAH, fatty acid amide hydrolase; URB597, cyclohexyl carbamic acid 3Ј-carbamoyl-biphenyl-3-yl ester; PPAR-␣, peroxisome proliferator-activated receptor type-␣; HPLC/MS, high-performance liquid chromatography/mass spectrometry; 2-AG, 2-arachidoloylglycerol.
Pharmacological Research, 2006
The O-arylcarbamate URB597 (cyclohexylcarbamic acid 3 -carbamoylbiphenyl-3-yl ester; also referred to as KDS-4103) is a potent inhibitor of fatty-acid amide hydrolase (FAAH), an intracellular serine hydrolase responsible for the inactivation of the endogenous cannabinoid anandamide. URB597 demonstrates a remarkable degree of selectivity for FAAH over other serine hydrolases (e.g. cholinesterases) or other components of the endocannabinoid system (e.g. cannabinoid receptors). However, in a proteomic-based selectivity screen based on the displacement of fluorophosphonate-rhodamine (FPR) from mouse brain proteins, it was recently shown that URB597 prevents FPR binding to triacylglycerol hydrolase (TGH) with a median inhibitory concentration of 192 nM. To determine whether this effect correlates with inhibition of TGH activity, we investigated the ability of URB597 to inhibit triolein hydrolysis in rat liver and heart tissues, which are rich in TGH, as well as white adipose tissue (WAT), which is rich in adipose triacylglycerol lipase (TGL) and hormone-sensitive lipase. The results show that URB597 does not affect triolein hydrolysis in any of these tissues at concentrations as high as 10 M, whereas it inhibits FAAH activity at low nanomolar concentrations. Moreover, intraperitoneal (i.p.) administration of URB597 at doses that maximally inhibit FAAH in vivo (0.3-3 mg kg −1 ) exerts no effect on triolein hydrolysis and tissue triacylglycerol (TAG) levels in rat liver, heart or WAT. The results indicate that URB597, while potent at inhibiting FAAH, does not affect TGH and TGL activities in rat tissues.
The fatty acid amide hydrolase inhibitor URB 597: interactions with anandamide in rhesus monkeys
British Journal of Pharmacology, 2011
The fatty acid amide hydrolase inhibitor URB 597 increases brain anandamide levels, suggesting that URB 597 could enhance the behavioural effects of anandamide. The goal of the current study was to examine and characterize the in vivo pharmacology of URB 597 alone and in combination with anandamide and D 9 -tetrahydrocannabinol (D 9 -THC) in two drug discrimination assays in rhesus monkeys.
Aryl Piperazinyl Ureas as Inhibitors of Fatty Acid Amide Hydrolase (FAAH) in Rat, Dog, and Primate
ACS Medicinal Chemistry Letters, 2012
A series of aryl piperazinyl ureas that act as covalent inhibitors of fatty acid amide hydrolase (FAAH) is described. A potent and selective (does not inhibit FAAH-2) member of this class, JNJ-40355003, was found to elevate the plasma levels of three fatty acid amides: anandamide, oleoyl ethanolamide, and palmitoyl ethanolamide, in the rat, dog, and cynomolgous monkey. The elevation of the levels of these lipids in the plasma of monkeys suggests that FAAH-2 may not play a significant role in regulating plasma levels of fatty acid ethanolamides in primates. Figure 1. Δ 9 -THC and substrates of FAAH. Letter pubs.acs.org/acsmedchemlett
A Sensitive and Specific Radiochromatographic Assay of Fatty Acid Amide Hydrolase Activity
Analytical Biochemistry, 1999
A radiochromatographic method has been set up in order to determine fatty acid amide hydrolase (FAAH) activity, based on reversed-phase high-performance liquid chromatography and on-line scintillation counting. The reaction products were separated using a C18 column eluted with methanol-water-acetic acid and quantitated with an external standard. Baseline separation of the acid product from the substrate was completed in less than 4 min, with a detection limit of 2.5 fmol arachidonic acid at a signal to noise ratio of 4:1. The method enabled to determine the kinetic constants (i.e., apparent K m of 2.0 ؎ 0.2 M and V max of 800 ؎ 75 pmol ⅐ min ؊1 ⅐ mg protein ؊1 toward anandamide) and the substrate specificity of human brain FAAH, as well as the extent of enzyme inhibition by some anandamide congeners. The femtomole sensitivity and the accuracy of the method allow detection and characterization of the activity of FAAH in very minute tissue samples or in samples where the enzymatic activity is very low.
Bioorganic & Medicinal Chemistry Letters, 2012
The structure-activity relationships for a series of heteroaryl urea inhibitors of fatty acid amide hydrolase (FAAH) are described. Members of this class of inhibitors have been shown to inactivate FAAH by covalent modification of an active site serine with subsequent release of an aromatic amine from the urea electrophile. Systematic Ames II testing guided the optimization of urea substituents by defining the structuremutagenicity relationships for the released aromatic amine metabolites. Potent FAAH inhibitors were identified having heteroaryl amine leaving groups that were non-mutagenic in the Ames II assay.
Lack of selectivity of URB602 for 2-oleoylglycerol compared to anandamide hydrolysisin vitro
British Journal of Pharmacology, 2007
Background and purpose: Two compounds, URB602 and URB754, have been reported in the literature to be selective inhibitors of monoacylglycerol lipase, although a recent study has questioned their ability to prevent 2-arachidonoyl hydrolysis by brain homogenates and cerebellar membranes. In the present study, the ability of these compounds to inhibit monoacylglycerol lipase and fatty acid amide hydrolase has been reinvestigated. Experimental approach: Homogenates and cell lines were incubated with test compounds and, thereafter, with either [ 3 H]-2oleoylglycerol or [ 3 H]-anandamide. Labelled reaction products were separated from substrate using chloroform: methanol extraction. Key results: In cytosolic fractions from rat brain, URB602 and URB754 inhibited the hydrolysis of 2-oleoylglycerol with IC 50 values of 25 and 48 mM, respectively. Anandamide hydrolysis by brain membranes was not sensitive to URB754, but was inhibited by URB602 (IC 50 value 17 mM). Hydrolysis of 2-oleoylglycerol by human recombinant monoacylglycerol lipase was sensitive to URB602, but not URB754. The lack of selectivity of URB602 for 2-oleoylglycerol compared to anandamide hydrolysis was also observed for intact RBL2H3 basophilic leukaemia cells. C6 glioma expressed mRNA for monoacylglycerol lipase, and hydrolyzed 2-oleoylglycerol in a manner sensitive to inhibition by methyl arachidonoyl fluorophosphonate but not URB754 or URB597. MC3T3-E1 mouse osteoblastic cells, which did not express mRNA for monoacylglycerol lipase, hydrolyzed 2-oleoylglycerol in the presence of URB597, but the hydrolysis was less sensitive to methyl arachidonoyl fluorophosphonate than for C6 cells. Conclusions and implications: The data demonstrate that the compounds URB602 and URB754 do not behave as selective and/or potent inhibitors of monoacylglycerol lipase.
British Journal of Pharmacology, 2009
Background and purpose: Genistein, a tyrosine kinase inhibitor used to block caveolae dependent endocytosis, reduces the cellular uptake of anandamide in RBL2H3 basophilic leukaemia cells. However, genistein is also a competitive inhibitor of fatty acid amide hydrolase, the enzyme responsible for anandamide hydrolysis. Here we have investigated whether inhibition of fatty acid amide hydrolase rather than inhibition of endocytosis is the primary determinant of genistein actions upon anandamide uptake. Experimental approach: Cellular uptake of anandamide, labelled in the arachidonoyl part of the molecule was assessed in four different cell lines using a standard method. Fatty acid amide hydrolase activity in homogenates and intact cells was measured using anandamide labelled in the ethanolamine part of the molecule. Key results: The fatty acid amide hydrolase inhibitor URB597 inhibited anandamide uptake into RBL2H3 cells and R3327 AT-1 prostate cancer cells, but not into 3T3-L1 preadipocytes or PC-3 prostate cancer cells. An identical pattern was seen with genistein. The related compound daidzein inhibited anandamide hydrolysis in homogenates and intact cells, and reduced its uptake into RBL2H3 and R3327 AT-1, but not PC-3 cells. Anandamide hydrolysis by cell homogenates was in the order RBL2H3 4 R3327 AT-1 4 PC-3 E3T3-L1. Conclusions and implications: The ability of genistein to inhibit anandamide uptake is mimicked by daidzein (which does not affect tyrosine kinase), and is only seen in cells that show sensitivity to URB597. This indicates that blockade of fatty acid amide hydrolase is the primary determinant of the effects of genistein on cellular anandamide uptake.