INVESTIGADORES
ASSEF Yanina Andrea
congresos y reuniones científicas
Título:
An outwardly rectifying chloride channel in BeWo choriocarcinoma cell line.
Autor/es:
MARINO G.; ASSEF Y.; KOTSIAS BA.
Lugar:
Salta
Reunión:
Congreso; XXXIX Reunion Anual de la Sociedad Argentina de Biofisica y 3rd Latin American protein Society; 2010
Institución organizadora:
Sociedad Aregentina de Biofisica
Resumen:
The outwardly rectifying chloride channel (ORCC) has been described in many epithelial and nonepithelial cells, although its molecular structure and physiological role are not well known. In this study, an ORCC was characterized in the trophoblastic cell line BeWo, human hormone-synthesizing cells which display many biochemical and morphological properties similar to those reported for the human cytotrophoblast. Ion channel activity was recorded in the inside-out configuration with standard patch-clamp technology. The channel under symmetrical chloride solution (Na+ free) in both sides of the membrane exhibited spontaneous activity with an outwardly rectifying current/voltage relationship and single-channel conductances of 15.1±7.4 and 48.0±11.9 pS for inwards and outwards currents, respectively (n=12). The channel was selective for Cl- over Na+ with the anionic permeability sequence I->Cl->F->gluconate. The open probability (Po) of the channel exhibited a membrane potential dependence, being greater at positive pulses.
The channel activity was inhibited by the sulphonylurea hypoglycaemic agent glibenclamide (50 and 100 μM) added to the cytoplasmic side of the patch. This blockade reduced the Po at higher positive and negative pulses following the voltage-dependence observed at control channels. In addition, the channel was blocked by intracellular diphenylamine-2-carboxylic acid (DPC, 500μM).
The physiological role of ORCC in BeWo cells is not clear at this time. Preliminary results showed that the incubation with increasing concentrations of chloride channel inhibitors (glibenclamide, DIDS and DPC) for 72 h reduced BeWo viability and cell proliferation, suggesting that the ORCC channel, as other Cl- channels could contribute to the trophoblastic cells proliferation.
