RESUMEN
BACKGROUND: In insects, continuous growth requires the periodic replacement of the exoskeleton. Once the remains of the exoskeleton from the previous stage have been shed during ecdysis, the new one is rapidly sclerotized (hardened) and melanized (pigmented), a process collectively known as tanning. The rapid tanning that occurs after ecdysis is critical for insect survival, as it reduces desiccation, and gives the exoskeleton the rigidity needed to support the internal organs and to provide a solid anchor for the muscles. This rapid postecdysial tanning is triggered by the "tanning hormone", bursicon. Since bursicon is released into the hemolymph, it has naturally been assumed that it would act on the epidermal cells to cause the tanning of the overlying exoskeleton. RESULTS: Here we investigated the site of bursicon action in Drosophila by examining the consequences on tanning of disabling the bursicon receptor (encoded by the rickets gene) in different tissues. To our surprise, we found that rapid tanning does not require rickets function in the epidermis but requires it instead in peptidergic neurons of the ventral nervous system (VNS). Although we were unable to identify the signal that is transmitted from the VNS to the epidermis, we show that neurons that express the Drosophila insulin-like peptide ILP7, but not the ILP7 peptide itself, are involved. In addition, we found that some of the bursicon targets involved in melanization are different from those that cause sclerotization. CONCLUSIONS: Our findings show that bursicon does not act directly on the epidermis to cause the tanning of the overlying exoskeleton but instead requires an intermediary messenger produced by peptidergic neurons within the central nervous system. Thus, this work has uncovered an unexpected layer of control in a process that is critical for insect survival, which will significantly alter the direction of future research aimed at understanding how rapid postecdysial tanning occurs.
Asunto(s)
Exoesqueleto/fisiología , Drosophila/fisiología , Hormonas de Insectos/metabolismo , Hormonas de Invertebrados/metabolismo , Animales , Proteínas de Drosophila/metabolismo , Epidermis/fisiología , Femenino , Masculino , Neuropéptidos/metabolismoRESUMEN
OBJECTIVE: To quantitate 2-methoxyestradiol (2-ME) in human corpus luteum (CL) of different ages and to determine the expression of cytochrome-P450-1A1 (CYP1A1) and catechol-O-methyl transferase (COMT) in CL and the action of 2-ME on P, vascular endothelial growth factor (VEGF) secretion, and luteal angiogenesis. DESIGN: Experimental study. SETTING: University division of reproductive endocrinology. PATIENT(S): Twenty-four women of reproductive age. INTERVENTION(S): CL was collected from 15 women during the minilaparotomy for tubal sterilization. Granulosa lutein cells were harvested 36 hours after hCG administration in patients undergoing IVF. MAIN OUTCOMES MEASURE(S): Levels of 2-ME were determined by high-performance liquid chromatography in CL. CYP1A1 and COMT were assessed by immunohistochemistry and Western blot. P and VEGF were measured by radioimmunoassay and ELISA. The angiogenic potential was analyzed using EA.hy926 cells. RESULT(S): Plasma levels of E2 decreased in the late luteal phase in association with an increase in luteal tissue of 2-ME concentrations. Concomitantly, there was a significant reduction of angiogenic activity in late CL. There was no significant variation in CYP1A1 and COMT expression in all CL. In physiological doses, 2-ME inhibited basal VEGF by granulosa lutein cells and diminished the angiogenic activity in conditioned media but did not prevent P and VEGF production stimulated by hCG. CONCLUSION(S): These data suggest the participation of 2-ME in physiological luteolysis by reducing angiogenesis. However, 2-ME did not prevent in vitro hCG stimulation of P biosynthesis, providing a mechanism for CL rescue in the cycle of conception.
Asunto(s)
Cuerpo Lúteo/irrigación sanguínea , Cuerpo Lúteo/metabolismo , Estradiol/análogos & derivados , Células Lúteas/metabolismo , Fase Luteínica/metabolismo , Neovascularización Fisiológica , Progesterona/biosíntesis , 2-Metoxiestradiol , Adulto , Catecol O-Metiltransferasa/metabolismo , Línea Celular , Medios de Cultivo Condicionados/metabolismo , Citocromo P-450 CYP1A1/metabolismo , Estradiol/sangre , Estradiol/metabolismo , Femenino , Humanos , Fase Luteínica/sangre , Factores de Tiempo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
OBJECTIVE: To evaluate nuclear factor kappaB (NF-κB) activation and NF-κB-p65 subunit activation, immunolocalization, and expression in the endometrium of healthy women and endometriosis patients throughout the menstrual cycle. DESIGN: Prospective observational study. SETTING: Affiliated hospital and university research laboratory. PATIENT(S): Twenty-four healthy women and 24 endometriosis patients. INTERVENTION(S): Menstrual, proliferative, and secretory endometrial biopsies. MAIN OUTCOME MEASURE(S): Assessment of NF-κB and p65 activation by protein-DNA binding assays and p65 localization and expression by immunohistochemistry. RESULT(S): Total NF-κB-DNA binding was constitutive and variable in human endometrium accross the menstrual cycle. Healthy women (physiologic conditions) showed higher p65-DNA binding in proliferative than in menstrual and secretory endometrium. Conversely, in endometriosis patients, p65-DNA binding was higher in proliferative and secretory endometrium than in menstrual endometrium. Endometrial epithelial cells showed higher p65 expression level score than endometrial stromal cells. CONCLUSION(S): NF-κB activity is constitutive, physiologic, and variable in human endometrium. The physiologic cyclic p65 activation pattern was altered in endometriosis patients, showing no cyclic variation between the proliferative and secretory phase of the menstrual cycle. The absence of decreased p65 activity in secretory endometrium from endometriosis patients is concurrent with progesterone resistance and could participate in endometrial biologic alterations during the implantation window in endometriosis patients.