RESUMEN
Though the decidua serves a critical function in implantation, the hormonal regulated pathway in decidualization is still elusive. Here we describe in detail the regional distribution and the effects of progesterone receptors (PGR), estrogen receptors (ESR), and MAPK activation on decidualization. We showed an increase in PGR A, PGR B, ESR1, and phosphorylated MAPK3-1 proteins (p-MAPK3-1), but not in ESR2, in the decidual tissue up to Day 8 of pregnancy. PGR was predominantly found in the nuclei of mesometrial decidual cells and of undifferentiated stromal cells where it colocalizes with ESR2 and ESR1. In the antimesometrial decidua, all the receptors showed cytoplasmic localization. MAPK was activated exclusively in undifferentiated stromal cells of the junctional zone between the antimesometrial and mesometrial decidua and at the border of the antimesometrial decidua. Treatment with the progesterone antagonist onapristone and/or the estrogen antagonist faslodex reduced the extent of decidual tissue and downregulated the levels of PGR and ESR1. The expression level of ESR2 was affected only by the progesterone receptor antagonist, while neither the antiprogestin nor the antiestrogen significantly modified the p-MAPK3-1 level. The inhibition of MAPK3-1 phosphorylation by PD98059 impaired the extent of decidualization and the closure reaction of the implantation chamber, and significantly downregulated ESR1. These results confirm a role of both steroid receptors in the growth and differentiation of the different decidual regions and suggest a new function for p-MAPK3-1 in regulating expression levels of ESR1, thereby maintaining the proliferation capacity of stromal cells and limiting the differentiation process in specified regions of decidual tissues.
Asunto(s)
Diferenciación Celular , Proliferación Celular , Endometrio/citología , Endometrio/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Receptores de Estrógenos/metabolismo , Receptores de Progesterona/metabolismo , Animales , Diferenciación Celular/efectos de los fármacos , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Proliferación Celular/efectos de los fármacos , Regulación hacia Abajo/efectos de los fármacos , Implantación del Embrión/efectos de los fármacos , Endometrio/efectos de los fármacos , Femenino , Antagonistas de Hormonas/farmacología , Fosforilación/efectos de los fármacos , Embarazo , Proteínas Gestacionales/antagonistas & inhibidores , Proteínas Gestacionales/metabolismo , Isoformas de Proteínas/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Ratas , Ratas Wistar , Receptores de Estrógenos/antagonistas & inhibidores , Receptores de Progesterona/antagonistas & inhibidores , Regulación hacia Arriba/efectos de los fármacosRESUMEN
We investigated the expression and cell localization of NOTCH1, NOTCH4, and the delta-like ligand DLL4 in corpus luteum (CL) from pregnant rats during prostaglandin F2alpha (PGF2alpha)-induced luteolysis. We also examined serum progesterone (P(4)) and CL proteins related to apoptosis after local administration of the notch inhibitor N-[N-(3,5-difluorophenacetyl-l-alanyl)]-S-phenylglycine t-butyl ester (DAPT). Specific staining for NOTCH1 and NOTCH4 receptors was detected predominantly in large and small luteal cells. Furthermore, in line with the fact that the notch intracellular domain is translocated to the nucleus, where it regulates gene expression, staining was evident in the nuclei of luteal cells. In addition, we detected diffuse cytoplasmic immunostaining for DLL4 in small and large luteal cells, in accordance with the fact that DLL4 undergoes proteolytic degradation after receptor binding. The mRNA expression of Notch1, Notch4, and Dll4 in CL isolated on Day 19 of pregnancy decreased significantly after administration of PGF2alpha. Consistent with the mRNA results, administration of PGF2alpha to pregnant rats on Day 19 of pregnancy decreased the protein fragment corresponding to the cleaved forms of NOTCH1/4 CL receptors. In contrast, no significant changes were detected in protein levels for the ligand DLL4. The local intrabursal administration of DAPT decreased serum P(4) levels and increased luteal levels of active caspase 3 and the BAX:BCL2 ratio 24 h after the treatment. These results support a luteotropic role for notch signaling to promote luteal cell viability and steroidogenesis, and they suggest that the luteolytic hormone PGF2alpha may act in part by reducing the expression of some notch system members.
Asunto(s)
Cuerpo Lúteo/metabolismo , Dinoprost/metabolismo , Luteólisis/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas Gestacionales/metabolismo , Receptor Notch1/metabolismo , Receptores Notch/metabolismo , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Animales , Apoptosis/efectos de los fármacos , Caspasa 3/metabolismo , Núcleo Celular/metabolismo , Cuerpo Lúteo/efectos de los fármacos , Cuerpo Lúteo/ultraestructura , Femenino , Regulación de la Expresión Génica , Péptidos y Proteínas de Señalización Intracelular , Luteólisis/sangre , Proteínas de la Membrana/genética , Fragmentos de Péptidos/metabolismo , Embarazo , Proteínas Gestacionales/antagonistas & inhibidores , Proteínas Gestacionales/genética , Progesterona/sangre , Inhibidores de Proteasas/farmacología , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Receptor Notch1/antagonistas & inhibidores , Receptor Notch1/genética , Receptor Notch4 , Receptores Notch/antagonistas & inhibidores , Receptores Notch/genética , Transducción de Señal/efectos de los fármacosRESUMEN
A group of eleven sesquiterpene lactones isolated from different Asteraceae species from north-western Argentina were investigated for their inhibitory action on the estrogen biosynthesis. Seven of them, of different skeleton types, were found to inhibit the aromatase enzyme activity in human placental microsomes, showing IC50 values ranging from 7 to 110 microM. The most active were the guaianolides 10-epi-8-deoxycumambrin B (compound 1), dehydroleucodin (compound 2) and ludartin (compound 3). These compounds were competitive inhibitors with an apparent Ki = 4 microM, Ki = 21 microM and Ki = 23 microM, respectively. Compounds 1 and 2 acted as type II ligands to the heme iron present in the active site of aromatase cytochrome P450 (P450arom). Besides, all of them failed to affect the cholesterol side-chain cleavage enzyme activity on human placental mitochondrias. This is the first report on the aromatase inhibitory activity of this group of natural compounds.