RESUMEN
Platelet-activating factor acetylhydrolases (PAFAHs) 1b2 and 1b3 are poorly characterized serine hydrolases that form a complex with a noncatalytic protein (1b1) to regulate brain development, spermatogenesis, and cancer pathogenesis. Determining physiological substrates and biochemical functions for the PAFAH1b complex would benefit from selective chemical probes that can perturb its activity in living systems. Here, we report a class of tetrahydropyridine reversible inhibitors of PAFAH1b2/3 discovered using a fluorescence polarization-activity-based protein profiling (fluopol-ABPP) screen of the NIH 300,000+ compound library. The most potent of these agents, P11, exhibited IC50 values of â¼40 and 900 nM for PAFAH1b2 and 1b3, respectively. We confirm selective inhibition of PAFAH1b2/3 in cancer cells by P11 using an ABPP protocol adapted for in situ analysis of reversible inhibitors and show that this compound impairs tumor cell survival, supporting a role for PAFAH1b2/3 in cancer.
Asunto(s)
1-Alquil-2-acetilglicerofosfocolina Esterasa/antagonistas & inhibidores , Evaluación Preclínica de Medicamentos/métodos , 1-Alquil-2-acetilglicerofosfocolina Esterasa/genética , 1-Alquil-2-acetilglicerofosfocolina Esterasa/metabolismo , Animales , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Línea Celular , Línea Celular Tumoral/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Polarización de Fluorescencia/métodos , Humanos , Concentración 50 Inhibidora , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/patología , Ratones , Proteómica/métodos , Piridinas/química , Piridinas/farmacología , Bibliotecas de Moléculas Pequeñas/farmacología , Relación Estructura-ActividadRESUMEN
The endocannabinoid 2-arachidonoylglycerol (2-AG) is biosynthesized by diacylglycerol lipases DAGLα and DAGLß. Chemical probes to perturb DAGLs are needed to characterize endocannabinoid function in biological processes. Here we report a series of 1,2,3-triazole urea inhibitors, along with paired negative-control and activity-based probes, for the functional analysis of DAGLß in living systems. Optimized inhibitors showed high selectivity for DAGLß over other serine hydrolases, including DAGLα (â¼60-fold selectivity), and the limited off-targets, such as ABHD6, were also inhibited by the negative-control probe. Using these agents and Daglb(-/-) mice, we show that DAGLß inactivation lowers 2-AG, as well as arachidonic acid and eicosanoids, in mouse peritoneal macrophages in a manner that is distinct and complementary to disruption of cytosolic phospholipase-A2. We observed a corresponding reduction in lipopolysaccharide-induced tumor necrosis factor-α release. These findings indicate that DAGLß is a key metabolic hub within a lipid network that regulates proinflammatory responses in macrophages.