Background: Apoptosis is induced by ethanol (EtOH) in human placental trophoblast cells, possibly disrupting placentation and contributing to intrauterine growth restriction in fetal alcohol spectrum disorder (FASD). EtOH induces programmed cell death in several embryonic tissues by raising intracellular Ca2+. Therefore, the role of Ca2+ signaling in EtOH-induced apoptosis was examined using human first trimester cytotrophoblast cell lines, examining the hypothesis that apoptosis is dependent on intracellular Ca2+ signaling. Methods: Using HTR-8/SVneo and SW.71 cytotrophoblast cell lines, real-time intracellular Ca2+ concentration was monitored by fluo-4 epifluorescence microscopy and apoptosis was assessed by flow cytometry of cells fluorescently labeled for DNA fragmentation (TUNEL) and annexin V binding. Results: Intracellular Ca2+ concentrations increased synchronously in all cells within 10 seconds of exposure to 50 mM EtOH, but not at lower EtOH concentrations (10 to 25 mM) incapable of inducing apoptosis. Trophoblast cells treated with inhibitors of Ca2+ signaling (BAPTA-AM, U73122, xestospongin D, BAPTA, SKF-96365) produced no intracellular Ca2+ transients after exposure to 50 mM EtOH and were protected from cell death induced by EtOH. Conclusions: EtOH-induced apoptosis in human cytotrophoblast cells, identified by DNA fragmentation and externalized phosphatidylserine, was dependent upon Ca2+ signaling. Both intracellular Ca2+ mobilization and extracellular Ca2+ influx were required, as well as phosphatidylinositol signaling. Inhibition by SKF-96365 suggests that the capacitative Ca2+ entry mechanism that utilizes TRPC channels was activated by EtOH. Apoptosis occurs downstream of Ca2+ signaling in trophoblasts and may contribute to placental insufficiency and poor fetal growth associated with FASD.
- Fetal Alcohol Spectrum Disorder
- Intracellular Signaling
- Intrauterine Growth Restriction
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Psychiatry and Mental health