Regulation of Expression and Localisation of the Na+/H+ Exchanger (NHE) 3 and the NHE Regulatory Factor 2 in Baboon Placental Syncytiotrophoblast by Oestrogen

Abstract

Our understanding of the regulation of the expression of the sodium hydrogen exchangers (NHE) and their regulatory factors (NHERF), which play important roles in fetal-placental homeostasis, is incomplete. We previously showed that the expression and localization of NHE3 and NHERF2 in the juxtanuclear compartment of the placental syncytiotrophoblast were markedly decreased between mid and late baboon pregnancy. In the current study, immunocytochemical fluorescence localization and level of NHE3/NHE1 and NHERF1/NHERF2 proteins were determined in late gestation in baboons untreated or treated throughout the second half of gestation with an aromatase inhibitor CGS 20267 alone (reduced estrogen levels by >95%) or with estradiol to determine whether estrogen regulated antiporter developmental expression. The immunocytochemical expression of NHE3 and NHERF2 in the juxtanuclear compartment was minimal in baboons untreated or treated with CGS 20267 plus estradiol (i.e. estrogen-replete) but extensive in estrogen-suppressed animals. Moreover, the abundant expression of NHERF2 in fetal vascular endothelium of estrogen-replete baboons was decreased in estrogen-suppressed animals. In contrast, expression and localization of NHE1 and NHERF1 in the placental syncytiotrophoblast were not altered by estrogen deprivation in baboons. Based on our current and previous findings, we propose that estrogen plays an important role in regulating localization and expression of components of the NHE system within and consequently development and function of the primate placental syncytiotrophoblast.

Uterine and fetal blood flow indexes and fetal growth assessment after chronic estrogen suppression in the second half of baboon pregnancy

“…Fetal-to-placental weight ratio has been suggested to be indicative of placental efficiency (46). Indeed, our laboratory (41) has shown that estrogen suppression causes a change in expression and localization within the baboon placental syncytiotrophoblast of the sodium-hydrogen exchangers (NHE), which control solute and water flux. Therefore, the apparent increase in placental weight in estrogendeprived baboons may be due to an accumulation of fluid/water and perhaps cellular volume secondary to changes in placental expression of the NHE system.…”

Regulation of Expression of Microvillus Membrane Proteins by Estrogen in Baboon Fetal Ovarian Oocytes1

“…The immunocytochemical detection of total ezrin, phosphorylated ezrin (T567), SLC9A3R1, and a-actinin was determined essentially as described previously [17,18]. Briefly, paraffin-embedded sections (4 lm) of fetal ovaries were mounted onto Superfrost/Plus microscope slides (Erie Scientific, Portsmouth, NH), heat fixed and, for diaminobenzidine (DAB) detection, endogenous peroxidase blocked with 0.3% H 2 O 2 (Sigma-Aldrich Corp., St. Louis, MO) in methanol (Fisher Scientific Co., Pittsburgh, PA).…”

“…In select experiments, ovarian samples also were incubated with rabbit polyclonal antibody to GAPDH (0.75 lg/ml; Abcam Inc., Cambridge, MA) to correct for loading/transfer. Membranes were washed and incubated with anti-mouse (a-actinin), anti-goat (ezrin), or anti-rabbit (SLC9A3R1, GAPDH) IgG horseradish peroxidase-conjugated secondary antibody (Vector Laboratories) diluted (1:20 000) in Solution II, washed, and proteins detected using enhanced chemiluminescence (Amersham Biosciences, Pittsburgh, PA), as described previously [18]. Specificity of the primary antibodies was determined by incubation of samples without primary antibody.…”