RESUMO
Neuroinflammation is a crucial process to maintain homeostasis in the central nervous system (CNS). However, chronic neuroinflammation is detrimental, and it is described in the pathogenesis of CNS disorders, including Alzheimer's disease (AD) and depression. This process is characterized by the activation of immune cells, mainly microglia. The role of the orphan G-protein-coupled receptor 55 (GPR55) in inflammation has been reported in different models. However, its role in neuroinflammation in respect to the arachidonic acid (AA) cascade in activated microglia is still lacking of comprehension. Therefore, we synthesized a novel GPR55 antagonist (KIT 10, 0.1-25 µM) and tested its effects on the AA cascade in lipopolysaccharide (LPS, 10 ng / mL)-treated primary rat microglia using Western blot and EIAs. We show here that KIT 10 potently prevented the release of prostaglandin E2 (PGE2), reduced microsomal PGE2 synthase (mPGES-1) and cyclooxygenase-2 (COX-2) synthesis, and inhibited the phosphorylation of Ikappa B-alpha (IκB-α), a crucial upstream step of the inflammation-related nuclear factor-kappaB (NF-κB) signaling pathway. However, no effects were observed on COX-1 and -2 activities and mitogen-activated kinases (MAPK). In summary, the novel GPR55 receptor antagonist KIT 10 reduces neuroinflammatory parameters in microglia by inhibiting the COX-2/PGE2 pathway. Further experiments are necessary to better elucidate its effects and mechanisms. Nevertheless, the modulation of inflammation by GPR55 might be a new therapeutic option to treat CNS disorders with a neuroinflammatory background such as AD or depression.
Assuntos
Anti-Inflamatórios/farmacologia , Ácido Araquidônico/metabolismo , Dinoprostona/metabolismo , Inflamação/tratamento farmacológico , Microglia/metabolismo , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Animais , Anti-Inflamatórios/química , Ciclo-Oxigenase 2/metabolismo , Inflamação/metabolismo , Inflamação/patologia , Lipopolissacarídeos/farmacologia , Microglia/efeitos dos fármacos , NF-kappa B/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Canabinoides , Transdução de SinaisRESUMO
BACKGROUND: Neuroinflammation plays a vital role in Alzheimer's disease and other neurodegenerative conditions. Microglia are the resident mononuclear immune cells of the central nervous system, and they play essential roles in the maintenance of homeostasis and responses to neuroinflammation. The orphan G-protein-coupled receptor 55 (GPR55) has been reported to modulate inflammation and is expressed in immune cells such as monocytes and microglia. However, its effects on neuroinflammation, mainly on the production of members of the arachidonic acid pathway in activated microglia, have not been elucidated in detail. METHODS: In this present study, a series of coumarin derivatives, that exhibit GPR55 antagonism properties, were designed. The effects of these compounds on members of the arachidonic acid cascade were studied in lipopolysaccharide (LPS)-treated primary rat microglia using Western blot, qPCR, and ELISA. RESULTS: We demonstrate here that the various compounds with GPR55 antagonistic activities significantly inhibited the release of PGE2 in primary microglia. The inhibition of LPS-induced PGE2 release by the most potent candidate KIT 17 was partially dependent on reduced protein synthesis of mPGES-1 and COX-2. KIT 17 did not affect any key enzyme involved on the endocannabinoid system. We furthermore show that microglia expressed GPR55 and that a synthetic antagonist of the GPR receptor (ML193) demonstrated the same effect of the KIT 17 on the inhibition of PGE2. CONCLUSIONS: Our results suggest that KIT 17 is acting as an inverse agonist on GPR55 independent of the endocannabinoid system. Targeting GPR55 might be a new therapeutic option to treat neurodegenerative diseases with a neuroinflammatory background such as Alzheimer's disease, Parkinson, and multiple sclerosis (MS).
Assuntos
Anti-Inflamatórios/farmacologia , Cumarínicos/farmacologia , Microglia/efeitos dos fármacos , Receptores de Canabinoides/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Animais Recém-Nascidos , Células Cultivadas , Córtex Cerebral/citologia , Ciclo-Oxigenase 1/genética , Ciclo-Oxigenase 1/metabolismo , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Dinoprostona/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Lipopolissacarídeos/farmacologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Microglia/metabolismo , Prostaglandina-E Sintases/genética , Prostaglandina-E Sintases/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Canabinoides/genética , Receptores Acoplados a Proteínas G/genéticaRESUMO
After prosperous domino reactions towards benzopyrans, the products were used as the starting material in Lewis acid catalyzed and organocatalytic Diels-Alder reactions to build up a tricyclic system. Herein, an asymmetric induction up to 96% enantiomeric excess was obtained by the use of imidazolidinone catalysts. This approach can be utilized to construct the tricyclic system in numerous natural products, in particular the scaffold of tetrahydrocannabinol (THC) being the most representative one. Compared with other published methods, condensation with a preexisting cyclohexane moiety in the precursor is needed to gain the heterogenic tricycle systems, whereas we present a novel strategy towards cannabinoid derivatives based on a flexible modular synthesis.
RESUMO
Over the last decade the use of urea derivatives as useful reagents, catalysts, and structural features in organic chemistry has increased rapidly. They now find utility as hydrogen-bond donors in organocatalysts and anion transporters, as important scaffolds in supramolecular chemistry, as lithiation directors, amination substrates, and promoters of metalation, and as substrates for novel rearrangement reactions. Highlighted herein is the remarkably rapid and recent development of the chemistry of ureas, which for many years had been considered unreactive, intractable, and of little value.
RESUMO
In the present study we synthesized 36 coumarin and 2H-chromene derivatives applying a recently developed umpoled domino reaction using substituted salicylaldehyde and alpha,beta-unsaturated aldehyde derivatives as starting compounds. In radioligand binding studies 5-substituted 3-benzylcoumarin derivatives showed affinity to cannabinoid CB(1) and CB(2) receptors and were identified as new lead structures. In further GTPgammaS binding studies selected compounds were shown to be antagonists or inverse agonists.
Assuntos
Cumarínicos/síntese química , Cumarínicos/farmacologia , Receptor CB1 de Canabinoide/agonistas , Receptor CB1 de Canabinoide/antagonistas & inibidores , Receptor CB2 de Canabinoide/agonistas , Receptor CB2 de Canabinoide/antagonistas & inibidores , Animais , Linhagem Celular , Cumarínicos/química , Agonismo Inverso de Drogas , Humanos , Ratos , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/metabolismo , Especificidade da Espécie , Relação Estrutura-AtividadeRESUMO
The orphan G-protein-coupled receptor GPR55, which is activated by 1-lysophosphatidylinositol and interacts with cannabinoid (CB) receptor ligands, has been proposed as a new potential drug target for the treatment of diabetes, Parkinson's disease, neuropathic pain, and cancer. We applied ß-arrestin assays to identify 3-substituted coumarins as a novel class of antagonists and performed an extensive structure-activity relationship study for GPR55. Selectivity versus the related receptors CB1, CB2, and GPR18 was assessed. Among the 7-unsubstituted coumarins selective, competitive GPR55 antagonists were identified, such as 3-(2-hydroxybenzyl)-5-isopropyl-8-methyl-2H-chromen-2-one (12, PSB-SB-489, IC50 = 1.77 µM, pA2 = 0.547 µM). Derivatives with long alkyl chains in position 7 were potent, possibly allosteric GPR55 antagonists which showed ancillary CB receptor affinity. 7-(1,1-Dimethyloctyl)-5-hydroxy-3-(2-hydroxybenzyl)-2H-chromen-2-one (69, PSB-SB-487, IC50 = 0.113 µM, KB = 0.561 µM) and 7-(1,1-dimethylheptyl)-5-hydroxy-3-(2-hydroxybenzyl)-2H-chromen-2-one (67, PSB-SB-1203, IC50 = 0.261 µM) were the most potent GPR55 antagonists of the present series.
Assuntos
Cumarínicos/síntese química , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Sítio Alostérico , Animais , Células CHO , Cumarínicos/química , Cumarínicos/farmacologia , Cricetinae , Células HEK293 , Humanos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fosforilação , Receptores de Canabinoides , Relação Estrutura-AtividadeRESUMO
Dianionic enolates formed from N'-aryl urea derivatives of amino acids undergo intramolecular C-arylation by attack of the enolate anion on the N'-aryl ring, leading to a hydantoin derivative of a quaternary amino acid. In situ IR studies allow identification of four intermediates on the reaction pathway.
Assuntos
Aminoácidos/química , Cetonas/síntese química , Ânions/síntese química , Ânions/química , Ciclização , Cetonas/química , Estrutura MolecularRESUMO
A series of 7-alkyl-3-benzylcoumarins was designed, synthesized, and tested at cannabinoid CB(1) and CB(2) receptors in radioligand binding and cAMP accumulation studies. 7-Alkyl-3-benzylcoumarins were found to constitute a versatile scaffold for obtaining potent CB receptor ligands with high potency at either CB(1) or CB(2) and a broad spectrum of efficacies. Fine-tuning of compound properties was achieved by small modifications of the substitution pattern. The most potent compounds of the present series include 5-methoxy-3-(2-methylbenzyl)-7-pentyl-2H-chromen-2-one (19a, PSB-SB-1201), a selective CB(1)antagonist (K(i) CB(1) 0.022 µM), 5-methoxy-3-(2-methoxybenzyl)-7-pentyl-2H-chromen-2-one (21a, PSB-SB-1202), a dual CB(1)/CB(2)agonist (CB(1)K(i) 0.032 µM, EC(50) 0.056 µM; CB(2)K(i) 0.049 µM, EC(50) 0.014 µM), 5-hydroxy-3-(2-hydroxybenzyl)-7-(2-methyloct-2-yl)-2H-chromen-2-one (25b, PSB-SB-1203), a dual CB(1)/CB(2) ligand that blocks CB(1) but activates CB(2) receptors (CB(1)K(i) 0.244 µM; CB(2)K(i) 0.210 µM, EC(50) 0.054 µM), and 7-(1-butylcyclopentyl)-5-hydroxy-3-(2-hydroxybenzyl)-2H-chromen-2-one (27b, PSB-SB-1204), a selective CB(2) receptor agonist (CB(1)K(i) 1.59 µM; CB(2)K(i) 0.068 µM, EC(50) 0.048 µM).