Expression and localization of AQP-3 and AQP-9 in human term placenta

DAMIANO ALICIA E; ZOTTA ELSA; GOLDSTEIN JORGE; MUZZOLINI, SILVANA; VAN HOEK, ALFRED; SILBERSTEIN CLAUDIA; IBARRA CRISTINA

Rochester

Congreso; International Federation of Placenta Associations Meeting 2000; 2000

Placenta Association of the Americas

The syncytiotrophoblast of human term placenta (HST) is a continuous, multinucleated structure with minimal tight junctions, which results from fusion of the underlying cytotrophoblast cells. Thus the transport of metabolites, ions and water from mother to fetus should take place primarily via transcellular routes. However, the possibility exits that wide, nonspecific, paracellular channels, allowing the passage of large hydrophilic molecules, may also be present. The aim of our work is to investigate the water pathways in HST. Here, we report the expression and localization of aquaporin 3 (AQP3) and aquaporin 9 (AQP9) in HST using RT-PCR, inmunoblotting, and inmunocytochemistry. Total RNA was purified from HST and RT-PCR data showed amplification of the NPA-NPA concensus sequence in the AQP3 and AQP9 genes. Western blot analysis using anti-AQP3 antibodies revealed a predominant band of 27-28 kDa in the enriched apical membrane fraction from HST. A similar band was detected using anti-AQP9 antibody. Inmunocytochemistry using these antibodies showed specific labelling associated with plasma membrane domains, while the cytoplasmic areas were devoid of staining. Since AQP3 and AQP9 are not only water channels, but also permit rapid passage of both urea and glycerol, the ocurrence of AQP3 and AQP9 in HST suggests a role for these proteins in the water and solute transport across the placenta.