Endothelin-1 attenuates apoptosis in cultured trophoblasts from term human placentas.
The authors test the hypothesis that endothelin-1 (ET-1) modulates apoptosis in human term trophoblasts. Primary cultures of cytotrophoblasts from term human placentas (n = 5) were cultured for 16 hours total or 24 hours prior to harvest at 72 hours in atmospheres of <1%, 8%, and 20% oxygen, in the presence of 10% serum, ET-1 (1-100 pmol/mL), both, or neither. The apoptotic cleavage products of poly-ADP-ribose polymerase and cytokeratin 18 filaments were quantified by Western analysis and immunocytochemistry. The expression of BAD, pBAD-serine 112, p53, and 2 isoforms of MDM2 were quantified by immunoblotting, and endothelin A and B receptors were analyzed by immunocytochemistry. Compared to vehicle control, increasing concentrations of ET-1 reduce by 3- to 6-fold the level of apoptosis in cytotrophoblasts exposed to serum-free conditions at 20% oxygen. Similarly, syncytiotrophoblast cultures grown for 24 hours without serum in 100 pmol/mL ET-1 show a 3-fold lower level of apoptosis compared with vehicle control. ET-1 significantly reduces apoptosis in cultures exposed to 20% oxygen but not in cultures exposed to 8% or 1% oxygen. The effect of ET-1 on apoptosis in 20% oxygen is accompanied by reduced p53 expression and is correlated with enhanced expression of endothelin B receptor, compared to cultures in 8% or 1% oxygen. ET-1 reduces apoptosis in cultured human trophoblasts, and this finding suggests a role for ET-1 in protecting trophoblasts against injury.
Cervar-Zivkovic
M
M
Department of Obstetrics and Gynecology, Washington University School of Medicine, St Louis, Missouri, USA. mila.cervarzivkovic@meduni-graz.at
Hu
C
C
Barton
A
A
Sadovsky
Y
Y
Desoye
G
G
Lang
U
U
Nelson
D M
DM
D017209:Apoptosis / Q000502:physiology*; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D019332:Endothelin-1 / Q000502:physiology*; D005260:Female; D006801:Humans; D007743:Labor, Obstetric / Q000502:physiology*; D010920:Placenta / Q000166:cytology / Q000502:physiology*; D011247:Pregnancy; D014327:Trophoblasts / Q000166:cytology / Q000502:physiology*
D016895:Culture Media, Serum-Free; D019332:Endothelin-1