RESUMEN
The histamine H4 receptor (H4R), a member of the G-protein coupled receptor family, has been considered as a potential therapeutic target for treating atopic dermatitis (AD). A large number of H4R antagonists have been disclosed, but no efficient agents controlling both pruritus and inflammation in AD have been developed yet. Here, we have discovered a novel class of orally available H4R antagonists showing strong anti-itching and anti-inflammation activity as well as excellent selectivity against off-targets. A pharmacophore-based virtual screening system constructed in-house successfully identified initial hit compound 9, and the subsequent homology model-guided optimization efficiently led us to discover pyrido[2,3- e]tetrazolo[1,5- a]pyrazine analogue 48 as a novel chemotype of a potent and highly selective H4R antagonist. Importantly, orally administered compound 48 exhibits remarkable efficacy on antipruritus and anti-inflammation with a favorable pharmacokinetic (PK) profile in several mouse models of AD. Thus, these data strongly suggest that our compound 48 is a promising clinical candidate for treatment of AD.
Asunto(s)
Dermatitis Atópica/tratamiento farmacológico , Antagonistas de los Receptores Histamínicos/síntesis química , Antagonistas de los Receptores Histamínicos/uso terapéutico , Receptores Histamínicos H4/antagonistas & inhibidores , Animales , Disponibilidad Biológica , Simulación por Computador , Descubrimiento de Drogas , Evaluación Preclínica de Medicamentos , Femenino , Antagonistas de los Receptores Histamínicos/farmacocinética , Inflamación/tratamiento farmacológico , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos ICR , Modelos Moleculares , Conformación Molecular , Simulación del Acoplamiento Molecular , Prurito/tratamiento farmacológico , Receptores Histamínicos H4/metabolismo , Relación Estructura-ActividadRESUMEN
Triggering receptor expressed on myeloid cells 2 (TREM2) is known to be involved in the anti-inflammatory response and osteoclast development. However, the role of TREM2 in adipogenesis or obesity has not yet been defined. The effect of TREM2 on adipogenesis and obesity was investigated in TREM2 transgenic (TG) mice on a high-fat diet (HFD). To block TREM2 signaling, a neutralizing fusion protein specific for TREM2 (TREM2-Ig) was used. TG mice were much more obese than wild-type mice after feeding with an HFD, independent of the quantity of food intake. These HFD-fed TG mice manifested adipocyte hypertrophy, glucose and insulin resistance, and hepatic steatosis. The expression of adipogenic regulator genes, such as peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α, was markedly increased in HFD-fed TG mice. Additionally, HFD-fed TG mice exhibited decreased Wnt10b expression and increased GSK-3ß (glycogen synthase kinase-3ß)-mediated ß-catenin phosphorylation. In contrast, the blockade of TREM2 signaling using TREM2-Ig resulted in the inhibition of adipocyte differentiation in vitro and a reduction in body weight in vivo by downregulating the expression of adipogenic regulators. Our data demonstrate that TREM2 promotes adipogenesis and diet-induced obesity by upregulating adipogenic regulators in conjunction with inhibiting the Wnt10b/ß-catenin signaling pathway.
Asunto(s)
Adipocitos/metabolismo , Adipogénesis/fisiología , Glicoproteínas de Membrana/metabolismo , Células Mieloides/metabolismo , Obesidad/metabolismo , Receptores Inmunológicos/metabolismo , Células 3T3-L1 , Adipocitos/citología , Adipocitos/inmunología , Animales , Calorimetría Indirecta , Diferenciación Celular/fisiología , Dieta Alta en Grasa , Metabolismo Energético/fisiología , Fibroblastos/citología , Fibroblastos/inmunología , Fibroblastos/metabolismo , Resistencia a la Insulina/fisiología , Masculino , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Ratones , Ratones Transgénicos , Células Mieloides/citología , Células Mieloides/inmunología , Obesidad/genética , Obesidad/inmunología , Cultivo Primario de Células , Receptores Inmunológicos/genética , Receptores Inmunológicos/inmunología , Transducción de Señal/fisiología , Vía de Señalización Wnt/fisiologíaRESUMEN
Bacterial ß-(1,3)-glucan has more advantages in terms of cost, yield and efficiency than that derived from mushrooms, plants, yeasts and fungi. We have previously developed a novel and high-yield ß-(1,3)-glucan produced by Agrobacterium sp. R259. This study aimed to elucidate the functional mechanism and therapeutic efficacy of bacterial ß-(1,3)-glucan in dextran sulfate sodium (DSS)-induced inflammatory bowel disease (IBD).Mice were orally pretreated with bacterial ß-(1,3)-glucan at daily doses of 2.5 or 5mg/kg for 2 weeks. After 6 days of DSS treatment, clinical assessment of IBD severity and expression of pro-inflammatory cytokines were evaluated. In vivo cell proliferation was examined by immunohistochemistry using Ki-67 and ER-TR7 antibodies. The frequency of regulatory T cells (Tregs) was analyzed by flow cytometry. Natural killer (NK) activity and IgA level were evaluated using NK cytotoxicity assay and ELISA.The deterioration of body weight gain, colonic architecture, disease score and histological score was recovered in DSS-induced IBD mice when pretreated with bacterial ß-(1,3)-glucan. The recruitment of macrophages and the gene expression of proinflammatory cytokines, such as IL-1ß, IL-6 and IL-17A/F, were markedly decreased in the colon of ß-(1,3)-glucan-pretreated mice. ß-(1,3)-Glucan induced the recovery of Tregs in terms of their frequency in DSS-induced IBD mice. Intriguingly, ß-(1,3)-glucan reversed the functional defects of NK cells and excessive IgA production in DSS-induced IBD mice.We conclude that bacterial ß-(1,3)-glucan prevented the progression of DSS-induced IBD by recovering the reduction of Tregs, functional defect of NK cells and excessive IgA production.