FAAH-Catalyzed C-C Bond Cleavage of a New Multitarget Analgesic Drug.
Alessia LigrestiCristoforo SilvestriRosa Maria VitaleJose L MartosFabiana PiscitelliJenny W WangMarco AllaràRobert W CarlingLivio LuongoFrancesca GuidaAnna IllianoAngela AmoresanoSabatino MaionePietro AmodeoDavid F WoodwardVincenzo Di MarzoGennaro MarinoPublished in: ACS chemical neuroscience (2018)
The discovery of extended catalytic versatilities is of great importance in both the chemistry and biotechnology fields. Fatty acid amide hydrolase (FAAH) belongs to the amidase signature superfamily and is a major endocannabinoid inactivating enzyme using an atypical catalytic mechanism involving hydrolysis of amide and occasionally ester bonds. FAAH inhibitors are efficacious in experimental models of neuropathic pain, inflammation, and anxiety, among others. We report a new multitarget drug, AGN220653, containing a carboxyamide-4-oxazole moiety and endowed with efficacious analgesic and anti-inflammatory activities, which are partly due to its capability of achieving inhibition of FAAH, and subsequently increasing the tissue concentrations of the endocannabinoid anandamide. This inhibitor behaves as a noncompetitive, slowly reversible inhibitor. Autoradiography of purified FAAH incubated with AGN220653, opportunely radiolabeled, indicated covalent binding followed by fragmentation of the molecule. Molecular docking suggested a possible nucleophilic attack by FAAH-Ser241 on the carbonyl group of the carboxyamide-4-oxazole moiety, resulting in the cleavage of the C-C bond between the oxazole and the carboxyamide moieties, instead of either of the two available amide bonds. MRM-MS analyses only detected the Ser241-assisted formation of the carbamate intermediate, thus confirming the cleavage of the aforementioned C-C bond. Quantum mechanics calculations were fully consistent with this mechanism. The study exemplifies how FAAH structural features and mechanism of action may override the binding and reactivity propensities of substrates. This unpredicted mechanism could pave the way to the future development of a completely new class of amidase inhibitors, of potential use against pain, inflammation, and mood disorders.
Keyphrases
- neuropathic pain
- molecular docking
- anti inflammatory
- spinal cord
- dna binding
- spinal cord injury
- oxidative stress
- molecular dynamics simulations
- fatty acid
- molecular dynamics
- chronic pain
- small molecule
- multiple sclerosis
- transition metal
- mass spectrometry
- risk assessment
- current status
- pain management
- sleep quality
- density functional theory
- transcription factor
- ionic liquid
- climate change
- depressive symptoms
- human health
- crystal structure