RESUMEN
Prostaglandin E2 (PGE2) plays pivotal roles in controlling microglial activation with the EP2 receptor, a PGE2 receptor subtype. Activated microglia are often reported to increase cyclooxygenase (COX)-2 expression, followed by PGE2 production, but it is unclear whether extracellular PGE2 is involved in microglial PGE2 synthesis. In the present study, we report that PGE2 increases COX-2 protein in microglia. In a culture system, PGE2 at 10-6 M for 3 h increased COX-2 and microsomal PGE synthase (mPGES)-1 mRNA levels, and reduced mPGES-2, but did not affect COX-1 or cytosolic PGE synthase (cPGES) in microglia. PGE2 at 10-6 M for 3 h also increased the COX-2 protein level, but did not affect COX-1, mPGES-1, mPGES-2, or cPGES. An EP2 agonist, ONO-AE1-259-01, also increased COX-2 and mPGES-1 mRNA levels, and reduced mPGES-2, but did not affect COX-1 or cPGES, whereas an EP1 agonist, ONO-DI-004, an EP3 agonist, ONO-AE-248, and an EP4 agonist, ONO-AE1-329, had no effect. Similar to PGE2, ONO-AE1-259-01 increased the COX-2 protein level, but did not affect COX-1, mPGES-1, mPGES-2, or cPGES. In addition, the effects of PGE2 were inhibited by an EP2 antagonist, PF-04418948, but not by an EP1 antagonist, ONO-8713, an EP3 antagonist, ONO-AE3-240, or an EP4 antagonist, ONO-AE3-208, at 10-6 M. On the other hand, lipopolysaccharide (LPS) increased PGE2 production, but the LPS-induced PGE2 production was not affected by ONO-8713, PF-04418948, ONO-AE3-240, or ONO-AE3-208. These results indicate that PGE2 increases COX-2 protein in microglia through the EP2 receptor supporting the idea that extracellular PGE2 has a triggering aspect for microglial activation.
Asunto(s)
Ciclooxigenasa 2/biosíntesis , Dinoprostona/farmacología , Microglía/efectos de los fármacos , Animales , Azetidinas/farmacología , Células Cultivadas , Corteza Cerebral/citología , Ciclooxigenasa 1/biosíntesis , Ciclooxigenasa 1/genética , Ciclooxigenasa 2/genética , Dinoprostona/análogos & derivados , Dinoprostona/biosíntesis , Inducción Enzimática/efectos de los fármacos , Proteínas de la Membrana/biosíntesis , Proteínas de la Membrana/genética , Éteres Metílicos/farmacología , Microglía/enzimología , Microsomas/efectos de los fármacos , Microsomas/enzimología , Prostaglandina-E Sintasas/biosíntesis , Prostaglandina-E Sintasas/genética , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Ratas , Ratas Wistar , Subtipo EP2 de Receptores de Prostaglandina E/agonistas , Subtipo EP2 de Receptores de Prostaglandina E/antagonistas & inhibidoresRESUMEN
We studied synthetic modifications of N-mercaptoacylamino acid derivatives to develop a new class of leukotriene A(4) (LTA(4)) hydrolase inhibitors. S-(4-Dimethylamino)benzyl-l-cysteine derivative 2a (SA6541) showed inhibitory activity against LTA(4) hydrolase (IC(50), 270nM) and selectivity over other metallopeptidases except angiotensin-converting enzyme (ACE, IC(50), 520nM). Modification at the para-substituent of the phenyl ring of compound 2a improved LTA(4) hydrolase inhibitory activity as well as selectivity over ACE. Finally, we obtained S-(4-cyclohexyl)benzy-l-cysteine derivatives 11l and 16i as potent and selective LTA(4) hydrolase inhibitors.
Asunto(s)
Cisteína/química , Epóxido Hidrolasas/antagonistas & inhibidores , Compuestos de Sulfhidrilo/síntesis química , Compuestos de Sulfhidrilo/farmacología , Inhibidores de la Enzima Convertidora de Angiotensina/síntesis química , Inhibidores de la Enzima Convertidora de Angiotensina/química , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Evaluación Preclínica de Medicamentos , Modelos Moleculares , Relación Estructura-Actividad Cuantitativa , Compuestos de Sulfhidrilo/químicaRESUMEN
We studied the synthetic modification of structurally similar N-mercaptoacyl-L-proline and (4R)-N-mercaptoacylthiazolidine-4-carboxylic acid to obtain potent leukotriene A(4) (LTA(4)) hydrolase inhibitors. An N-mercaptoacyl group, (2S)-3-mercapto-2-methylpropionyl group, was effective for both scaffolds. Additional introduction of a large substituent such as 4-isopropylbenzylthio (3f), 4-tert-butylbenzylthio (3l) or 4-cyclohexylbenzylthio group (3m) with (S)-configuration at the C(4) position of proline yielded much more potent LTA(4) hydrolase inhibitors (IC(50); 52, 31, and 34 nM, respectively) than captopril (IC(50); 630,000 nM).