Expression and localization of ion and water channels in trophoblastic cells from normal and pathological placenta.

DAMIANO, ALICIA E; ZOTTA ELSA; IBARRA CRISTINA

Buenos Aires

Jornada; Jornadas Anuales de la Sociedad Argentina de Biología; 2000

SAB

The syncytiotrophoblast of normal human placenta (hST) is a continuous, multi-nucleated 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 primary via transcellular routes. Here, we report the expression and localization of CFTR (cystic fibrosis transmembrane conductance regulator), APXL (human homologue of the apical protein of Xenopus laevis), AQP3 and AQP9 (aquaporin 3 and 9) by RT-PCR, immunoblotting and immunocytochemistry. Total RNA was purified from hST and the RT-PCR technique was applied using primers flanking highly conserved regions of CFTR, APXL and AQPs. PCR amplification bands were 295 bp for CFTR, 360 and 404 bp for APXL, and 398 and 393 bp for AQP3 and AQP9, respectively. Western blot analysis in a plasma membrane fraction from hST using specific antibodies, showed a band of ~170 kDa for CFTR, ~160 kDa for APXL and 27-28 kDa for AQPs. The immunolocalization was restricted to the plasma membrane domains of hST. CFTR and APXL were also found in hydatidiform mole, a placental trophoblastic disease characterized by greatly enlarged avascular ¨grape-like¨ villi. The functional importance of these channels in normal and pathological placenta need to be elucidated.