Correlation between hCG, cAMP and AQP9 in human placenta

MARINO GABRIELA; CASTRO-PARODI MAURICIO; ZOTTA ELSA; DAMIANO ALICIA E

Adelaida, Australia

Congreso; International Federation of Placental Associations Meeting 2009; 2009

INTERNATIONAL FEDERATION OF PLACENTA ASSOCIATIONS

Since trophoblastic abnormalities play a central role in the pathophysiology of preeclampsia, it is conceivable that some placental hormone profiles such as an increased secretion of human chorionic gonadotropin (hCG) are modified in the maternal circulation, which could affect the placental function. We have described in preeclamptic pregnancies that there are elevated levels of serum hCG with an increased of aquaporin-9 (AQP9) expression in the syncytiotrophoblast (hST. Several reports indicate that AQP9 expression may be mediated by some factors induced by cAMP.In addition hCG signal transduction usually involves cAMP signaling.Here, we are focused on the hypothesis that there is a correlation between the increased levels of hCG and AQP9 expression in preeclamptic placentas, involving a cAMP dependent pathway. Normal placental explants were cultured at different times with 20 mIU/ml of recombinant hCG and 100-500 µM 8-bromo-cAMP (8-Br-cAMP), a potent cAMP analogue. Semiquantitative Western blot and immunohistochemistry were performed to evaluate AQP9 expression and localization. In Western blots we observed a stimulatory effect on AQP9 protein expression after hCG treatment.AQP9 was localized in the apical membrane of hST and in the cytoplasm, and similar results were obtained with placental explants incubated with 8-Br –cAMP, this effect being time and dose dependent. Our results suggest that hCG may be implicated in the regulation of AQP9 expression involving a cAMP dependent pathway in hST.