Publication Date:
2014-03-04
Description:
by Paula Díaz, Amber M. Wood, Colin P. Sibley, Susan L. Greenwood Regulation of human placental syncytiotrophoblast renewal by cytotrophoblast migration, aggregation/fusion and differentiation is essential for successful pregnancy. In several tissues, these events are regulated by intermediate conductance Ca 2+ -activated K + channels (IK Ca ), in part through their ability to regulate cell volume. We used cytotrophoblasts in primary culture to test the hypotheses that IK Ca participate in the formation of multinucleated syncytiotrophoblast and in syncytiotrophoblast volume homeostasis. Cytotrophoblasts were isolated from normal term placentas and cultured for 66 h. This preparation recreates syncytiotrophoblast formation in vivo , as mononucleate cells (15 h) fuse into multinucleate syncytia (66 h) concomitant with elevated secretion of human chorionic gonadotropin (hCG). Cells were treated with the IK Ca inhibitor TRAM-34 (10 µM) or activator DCEBIO (100 µM). Culture medium was collected to measure hCG secretion and cells fixed for immunofluorescence with anti-IK Ca and anti-desmoplakin antibodies to assess IK Ca expression and multinucleation respectively. K + channel activity was assessed by measuring 86 Rb efflux at 66 h. IK Ca immunostaining was evident in nucleus, cytoplasm and surface of mono- and multinucleate cells. DCEBIO increased 86 Rb efflux 8.3-fold above control and this was inhibited by TRAM-34 (85%; p
Electronic ISSN:
1932-6203
Topics:
Medicine
,
Natural Sciences in General
