Expression and Regulation of Glucocorticoid Receptor in Human Placental Villous Fibroblasts

Abstract

The human placenta is a glucocorticoid (GC)-responsive organ consisting of multiple cell types including smooth muscle cells, fibroblasts, and trophoblast that demonstrate changes in gene expression after hormone treatment. However, little is known about the relative expression or activity of the GC receptor (GR) among the various placental cell types. Normal term human placentas were examined by immunohistochemistry using either GR phosphorylation site-specific antibodies that are markers for various activation states of the GR or a GR antibody that recognizes the receptor independent of its phosphorylation state (total GR). We found strong total GR and phospho-GR immunoreactivity in stromal fibroblasts of terminal villi, as well as perivascular fibroblasts and vascular smooth muscle cells of the stem villi. Lower levels of both total GR and phospho-GR were found within cytotrophoblast cells relative to fibroblasts, whereas syncytiotrophoblast showed very little total GR or phospho-GR immunoreactivity. This pattern holds true for immunoblot analysis of extracts from cell fractions cultured ex vivo. In cultured placental fibroblasts, phosphorylation of GR increased upon short-term GC treatment, consistent with a role for GR phosphorylation in receptor transactivation. Total GR levels were reduced by nearly 90% after long-term hormone treatment; however, this down-regulation was independent of changes in GR mRNA levels. These findings demonstrate that GR levels in fibroblasts can be modulated by changes in hormone exposure. Such cell type-specific differences in GR protein expression and phosphorylation may provide the means of differentially regulating the GC response among the cells of the human placenta. (Endocrinology 146: 4619 -4626, 2005)

Cell Type-specific Expression and Function of Toll-like Receptors 2 and 4 in Human Placenta: Implications in Fetal Infection

“…Expression of αSMA in these cells and not in SCTs was revealed by Western blotting. Protocols using collagenase digestion without immunopurification have been used by our group and others to previously isolate vimentin-positive and αSMA-positive FIBs from term placenta [17,25]. The current protocols allowed for the simultaneous separation of SCTs and mFIBs from the same placenta.…”

“…Immunohistochemical localization of proteins in human term placentas was carried out essentially as we have previously described [17]. Formalin-fixed samples were embedded in paraffin and cut into 5 μm sections.…”

Enhanced Human Decidual Cell–Expressed FKBP51 May Promote Labor-Related Functional Progesterone Withdrawal

“…24 SCTs were obtained by spontaneous differentiation of CYTs after 72 hours of culture, as previously described. 25 CYTs and SCTs were treated with 10 À7 mol/L Dex for 6 hours, and RNA was extracted for further studies.…”

Differential recruitment of glucocorticoid receptor phospho-isoforms to glucocorticoid-induced genes

“…We have generated antibodies that specifically recognize GR phosphorylated on S203, S211 or S226, and we have used these to investigate hormone-dependent GR phosphorylation [9,[14][15][16]. GR S203 and S226 are phosphorylated in both the absence and presence of agonists, such as dexamethasone, whereas phosphorylation of S211 is observed upon agonist treatment, but not understand basal conditions.…”