RESUMEN
OBJECTIVES: Cadmium (Cd) induces reactive oxygen species (ROS)-mediated hepatocyte apoptosis and consequential liver disorders. This study aimed to investigate the effect of magnesium isoglycyrrhizinate (MgIG) on Cd-induced hepatotoxicity. METHODS: L02 and AML-12 cells were used to study MgIG hepatoprotective effects. Cd-evoked apoptosis, ROS and protein phosphatase 2A (PP2A)/c-Jun N-terminal kinase (JNK) cascade disruption were analysed by cell viability assay, 6-diamidino-2-phenylindole (DAPI) and TdT-mediated dUTP Nick-End Labeling (TUNEL) staining, ROS imaging and Western blotting. Pharmacological and genetic approaches were used to explore the mechanisms. KEY FINDINGS: We show that MgIG attenuated Cd-evoked hepatocyte apoptosis by blocking JNK pathway. Pre-treatment with SP600125 or ectopic expression of dominant-negative c-Jun enhanced MgIG's anti-apoptotic effects. Further investigation found that MgIG rescued Cd-inactivated PP2A. Inhibition of PP2A activity by okadaic acid attenuated the MgIG's inhibition of the Cd-stimulated JNK pathway and apoptosis; in contrast, overexpression of PP2A strengthened the MgIG effects. In addition, MgIG blocked Cd-induced ROS generation. Eliminating ROS by N-acetyl-l-cysteine abrogated Cd-induced PP2A-JNK pathway disruption and concurrently reinforced MgIG-conferred protective effects, which could be further slightly strengthened by PP2A overexpression. CONCLUSIONS: Our findings indicate that MgIG is a promising hepatoprotective agent for the prevention of Cd-induced hepatic injury by mitigating ROS-inactivated PP2A, thus preventing JNK activation and hepatocyte apoptosis.
Asunto(s)
Cadmio/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Hígado/efectos de los fármacos , Proteína Fosfatasa 2/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Saponinas/farmacología , Triterpenos/farmacología , Animales , Apoptosis , Línea Celular , Supervivencia Celular , Enfermedad Hepática Inducida por Sustancias y Drogas/prevención & control , Medicamentos Herbarios Chinos/farmacología , Medicamentos Herbarios Chinos/uso terapéutico , Contaminantes Ambientales/toxicidad , Ácido Glicirrínico , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Hepatocitos/patología , Humanos , Hígado/citología , Hígado/metabolismo , Sistema de Señalización de MAP Quinasas , Ratones , Estrés Oxidativo/efectos de los fármacos , Saponinas/uso terapéutico , Transducción de Señal , Triterpenos/uso terapéuticoRESUMEN
A structure-hopping strategy was applied to discover a series of novel 4-aminoquinoline-3-carboxamide derivatives as potent, reversible BTK inhibitors. Compared to the previously described cinnoline scaffold compounds, the 4-aminoquinoline analogues showed significantly improved drug-like properties, especially in their aqueous solubility. The most potent compound, 25, displayed a stronger inhibitory effect on both BTKWT (IC50 = 5.3 nM) and BTKC481S (IC50 = 39 nM). In a rodent collagen-induced arthritis model, compound 25 efficiently reduced paw swelling without a loss in body weight. On the basis of potency, drug-like properties, stability, and noncovalent mode of inhibition, our representative inhibitors could have a promising profile to be treatments for a wide range of autoimmune diseases.
Asunto(s)
Agammaglobulinemia Tirosina Quinasa/antagonistas & inhibidores , Aminoquinolinas/química , Aminoquinolinas/uso terapéutico , Artritis Experimental/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/uso terapéutico , Agammaglobulinemia Tirosina Quinasa/metabolismo , Aminoquinolinas/farmacocinética , Aminoquinolinas/farmacología , Animales , Artritis Experimental/metabolismo , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/metabolismo , Perros , Diseño de Fármacos , Haplorrinos , Humanos , Masculino , Ratones , Simulación del Acoplamiento Molecular , Inhibidores de Proteínas Quinasas/farmacocinética , Inhibidores de Proteínas Quinasas/farmacología , Ratas , Ratas Sprague-DawleyRESUMEN
High fructose intake is a risk of glomerular podocyte dysfunction. Podocyte apoptosis has emerged as a major cause of podocyte loss, exacerbating proteinuria. Magnesium isoglycyrrhizinate (MgIG) is usually used as a hepatoprotective agent in clinic. Liver and kidney injury often occurs in human diseases. Recent report shows that MgIG improves kidney function. In this study, we found that MgIG significantly alleviated kidney dysfunction, proteinuria and podocyte injury in fructose-fed rats. It also restored fructose-induced podocyte apoptosis in rat glomeruli and cultured differentiated podocytes. Of note, high-expression of miR-193a, downregulation of Wilms' tumor protein (WT1) and RelA, as well as upregulation of C-Maf inducing protein (C-mip) were observed in these animal and cell models. The data from the transfection of miR-193a mimic, miR-193a inhibitor, WT1 siRNA or LV5-WT1 in cultured differentiated podocytes showed that fructose increased miR-193a to down-regulate WT1, and subsequently activated C-mip to suppress RelA, causing podocyte apoptosis. These disturbances were significantly attenuated by MgIG. Taken together, these results provide the first evidence that MgIG restrains fructose-induced podocyte apoptosis at least partly through inhibiting miR-193a to upregulate WT1, supporting the application of MgIG with a novel mechanism-of-action against podocyte apoptosis associated with fructose-induced kidney dysfunction.
Asunto(s)
Apoptosis/fisiología , Fructosa/toxicidad , MicroARNs/metabolismo , Podocitos/metabolismo , Saponinas/farmacología , Triterpenos/farmacología , Proteínas WT1/metabolismo , Animales , Apoptosis/efectos de los fármacos , Línea Celular , Relación Dosis-Respuesta a Droga , Medicamentos Herbarios Chinos/farmacología , Humanos , Masculino , MicroARNs/antagonistas & inhibidores , Podocitos/efectos de los fármacos , Ratas , Ratas Sprague-DawleyRESUMEN
To discover new potent cytotoxic steroidal saponins, a series of tigogenin neoglycosides were synthesized via oxyamine neoglycosylation for the first time. The preliminary bioassays for their in vitro antitumor activities against five human cancer cell lines (A375, A-549, HCT-116, HepG2 and MCF-7) were conducted. The results revealed a sugar-dependent activity profile of their cytotoxicity, the glycoconjugation converted the non-active tigogenin to the most potential product Tg29 ((3R)-N-methoxyamino-tigogenin-ß-2-deoxy-d-galactoside) with IC50 value of 2.7µM and 4.6µM against HepG2 and MCF-7 cells respectively. And the 3R-tigogenin neoglycosides exhibited enhanced antitumor activity while the 3S-tigogenin almost showed no activity. Among the five cell lines, HepG2 and MCF-7 cells showed more sensitive cytotoxic responses to the products. Therefore, the neoglycosylation could be a promising strategy for the synthesis of antitumor steroidal saponins and it also proved the essential role of carbohydrate moiety of steroidal saponins in the biological activity.