RESUMEN
Wnt5a is a ligand that activates the noncanonical Wnt signaling pathways (beta-catenin-independent pathways). Human neutrophils expressed several Wnt5a receptors, such as Frizzled 2, 5 and 8. Stimulation of human neutrophils with Wnt5a caused chemotactic migration and the production of two important chemokines, CXCL8 and CCL2. CCL2 production by Wnt5a was mediated by a pertussis toxin-sensitive G-protein-dependent pathway. Wnt5a also stimulated the phosphorylation of three mitogen-activated protein kinases (MAPKs: ERK, p38 MAPK and JNK) and Akt. Inhibition of ERK, p38 MAPK or JNK by specific inhibitors induced a dramatic reduction in Wnt5a-induced CCL2 production. Supernatant collected from lipopolysaccharide-stimulated macrophages induced neutrophil chemotaxis, which was significantly inhibited by anti-Wnt5a antibody. Our results suggested that Wnt5a may contribute to neutrophil recruitment, mediating the inflammation response.
Asunto(s)
Animales , Humanos , Ratones , Factor de Transcripción Activador 2/metabolismo , Separación Celular , Quimiocinas/biosíntesis , Quimiotaxis/efectos de los fármacos , Medios de Cultivo Condicionados/farmacología , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Proteínas de Unión al GTP/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Lipopolisacáridos/farmacología , Macrófagos/efectos de los fármacos , FN-kappa B/metabolismo , Neutrófilos/citología , Toxina del Pertussis/farmacología , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores Wnt/metabolismo , Fosfolipasas de Tipo C/metabolismo , Proteínas Wnt/farmacología , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
In this study, we determined mode of action of a novel carbamoyloxy arylalkanoyl arylpiperazine compound (SKL-NP) on hyperpolarization-activated cyclic nucleotide-gated (HCN) channel currents (Ih) that plays important roles in neuropathic pain. In small or medium-sized dorsal root ganglion (DRG) neurons (<40 microm in diameter) exhibiting tonic firing and prominent Ih, SKL-NP inhibited Ih and spike firings in a concentration dependent manner (IC50=7.85 microM). SKL-NP-induced inhibition of Ih was blocked by pretreatment of pertussis toxin (PTX) and N-ethylmaleimide (NEM) as well as 8-Br-cAMP, a membrane permeable cAMP analogue. These results suggest that SKL-NP modulates Ih in indirect manner by the activation of a Gi-protein coupled receptor that decreases intracellular cAMP concentration. Taken together, SKL-NP has the inhibitory effect on HCN channel currents (I h) in DRG neurons of rats.