May CFTR Regulate the Functional Expression of AQP9 in Human Placenta?

LEVI LORENA; ZOTTA ELSA; CASTRO-PARODI MAURICIO; DAMIANO ALICIA E

Kingston, Ontario- Canadá

Congreso; 13th International Federation of Placenta Associations; 2007

International Federation of Placenta Associations

Normal fetal growth and development is critically dependent on sufficient transport of nutrients, metabolites, ions and water across the placenta. The syncytiotrophoblast of term human placenta (hST) is a continuous multinucleated structure with minimal tight junctions, which results from the fusion of the underlying cytotrophoblast cells. Thus, the transport of metabolites, ions and water from mother to fetus could take place primarily via transcellular routes. Transcellular water and urea transport across hST may be facilitated by aquaporins (AQPs), water permeable membrane proteins widely expressed in cells and tissues and/or by urea transporters type UT. We previously observed an increase of AQP9 expression in preeclamptic placenta with a lack of functionality of AQP9 for water and mannitol. There is strong evidence that cystic fibrosis transmembrane conductance regulator (CFTR) regulates the AQP9 functionality. Here we have explored the possible interaction between CFTR and AQP9 in human placenta. We have determined the expression and co-localization of CFTR and AQP9 in normal and preeclamptic placentas by Western Blot and immunohistochemistry. We observed that CFTR localizes in the apical plasma membrane in normal placentas, but it decreases in preeclamptic placentas where AQP9 is significantly augmented. Semiquantitative Western Blot assay showed that CFTR decreased about 2 folds in preeclamptic placentas. These results suggest that the lack of functionality of AQP9 in preeclamptic placentas may be caused by the decrease of CFTR in the apical membrane of hST. Further work is necessary to elucidate the mechanisms that regulate the expression of these proteins, and if they may play a role in the pathogenesis of the preeclampsia.