Nuclear Progesterone Receptor Expression Research Articles

Effects of mifepristone, a model compound with anti-progestogenic activity, on the development of African clawed frog (Xenopus laevis)

The objective of this study was to assess the effects of a model substance with anti-progestogenic activity on development of African clawed frog (Xenopus laevis) from tadpole to juvenile stage. Mifepristone, a synthetic progesterone receptor-blocking steroid hormone used in medicine as an abortifacient, was chosen as a model compound with anti-progestogenic activity. In the experiment, African clawed frog tadpoles were exposed to mifepristone at three concentrations (2, 21, and 215 ng L−1). A control group was exposed to dimethyl sulfoxide (DMSO; 0.001 %). The experiment started when tadpoles reached stages 47–48 according to Nieuwkoop and Faber (NF; 1994) and continued until stage NF 66, when metamorphosis was complete. Exposure to mifepristone had no significant effect on the rate of tadpole development, occurrence of morphological anomalies, weight, body length, or sex ratio. Mortality was within an acceptable range of 0–3.6 % throughout the test and did not differ among the groups. Histopathological examination of the gonads and thyroid gland revealed no significant changes. Therefore, we can conclude that mifepristone had no negative effect on development of the African clawed frog up to juvenile stage. Nevertheless, at the highest tested mifepristone concentration (215 ng L−1), gene expression analysis revealed up-regulation of mRNA expression of nuclear progesterone receptor (npr), membrane progesterone receptor (mpr), estrogen receptor beta (esrβ), and luteinizing hormone (lh) in the brain–pituitary complex of exposed frogs at stage NF 66. Higher mRNA expression of npr was also found in frogs exposed to 22 ng L−1 mifepristone compared to the solvent control. These findings confirmed the anti-progestogenic activity of mifepristone in frogs because the up-regulation of progesterone receptors occurs if progesterone availability in the body is reduced. All the observed changes in combination may have negative consequences for reproduction and reproductive behavior later in life.

037 Nuclear progesterone receptor expression and localisation in growing bovine oocytes

037 Nuclear progesterone receptor expression and localisation in growing bovine oocytes

Developing a reproducible protocol for culturing functional confluent monolayers of differentiated equine oviduct epithelial cells†.

We describe the development of two methods for obtaining confluent monolayers of polarized, differentiated equine oviduct epithelial cells (EOEC) in Transwell inserts and microfluidic chips. EOECs from the ampulla were isolated post-mortem and seeded either (1) directly onto a microporous membrane as differentiated EOECs (direct seeding protocol) or (2) first cultured to a confluent de-differentiated monolayer in conventional wells, then trypsinized and seeded onto a microporous membrane (re-differentiation protocol). Maintenance or induction of EOEC differentiation in these systems was achieved by air–liquid interface introduction. Monolayers cultured via both protocols were characterized by columnar, cytokeratin 19-positive EOECs in Transwell inserts. However, only the re-differentiation protocol could be transferred successfully to the microfluidic chips. Integrity of the monolayers was confirmed by transepithelial resistance measurements, tracer flux, and the demonstration of an intimate network of tight junctions. Using the direct protocol, 28% of EOECs showed secondary cilia at the apical surface in a diffuse pattern. In contrast, re-differentiated polarized EOECs rarely showed secondary cilia in either culture system (>90% of the monolayers showed <1% ciliated EOECs). Occasionally (5–10%), re-differentiated monolayers with 11–27% EOECs with secondary cilia in a diffuse pattern were obtained. Additionally, nuclear progesterone receptor expression was found to be inhibited by simulated luteal phase hormone concentrations, and sperm binding to cilia was higher for re-differentiated EOEC monolayers exposed to estrogen–progesterone concentrations mimicking the follicular rather than luteal phase. Overall, a functional equine oviduct model was established with close morphological resemblance to in vivo oviduct epithelium.

Evaluation of progesterone receptor expression in low- and high-grade astrocytomas.

Gliomas are tumors originating from glial cells. Gliomas are the most common primary neoplasms of the central nervous system, with astrocytomas being the most prevalent glioma subtype. Progesterone regulates several reproductive processes, such as ovulation and sexual behavior, and influences neuronal excitability, learning, and the neoplastic proliferation of glial cells. Progesterone functions mainly by interacting with intracellular progesterone receptors to modify the expression of the genes involved in cell proliferation, angiogenesis, and epidermal growth factor production. As not many studies on the hormone receptors in glial tumors have been reported, the objective of this study was to evaluate the expression of these proteins in astrocytomas and to determine whether their expression levels vary according to the tumor grade. This was a retrospective study using glial tumor paraffin blocks obtained from the São Marcos Hospital Pathology Department archives. Forty cases were divided equally into two groups, based on histological types and the World Health Organization criteria (low- and high-grade tumors). Progesterone receptor expression was analyzed by immunohistochemistry. The data were statistically analyzed using the Mann-Whitney U test and Spearman's correlation coefficient; results with p<0.05 were considered statistically significant. There were no statistically significant differences between the mean nuclear progesterone receptor expression of low-grade (0.1495) and high-grade (0.0937) astrocytomas (p=0.2). Progesterone receptors are present in both low- and high-grade gliomas; however, there is no significant difference in the levels of progesterone receptor expression between the tumor grades.

Expression of nuclear progesterone receptor, progesterone receptor membrane components 1 and 2 and prostaglandin-endoperoxide synthase 2 in the endometrium and oviduct of spontaneously ovulating cats

Although ovulations not followed by pregnancy occur regularly in cats, differences in endometrial function between cats in the luteal and non-luteal phase have not been studied so far. Progesterone exerts its effects through a nuclear progesterone receptor (PGR) and via cell-membrane bound receptors referred to as progesterone receptor membrane component (PGRMC) 1 and 2. Progesterone receptor expression is regulated by gonadal steroid hormones and therefore may change throughout the oestrous cycle. Protein expression of PGR, PGRMC-1 and 2 and prostaglandin-endoperoxide synthase 2 (PTGS2) was analysed in the endometrium and oviduct of non-pregnant female cats in the follicular (n = 8) and luteal phase (n = 9). We hypothesized that the presence of corpora lutea (CL) is associated with downregulation of progesterone receptors and PTGS2. Cells of the luminal endometrial epithelium, endometrial stroma and oviductal epithelium were assessed by immunohistochemistry. The PGR protein expression was more pronounced in the endometrial epithelium than stroma (p < 0.001) and less pronounced in cats with a CL than without CL (p < 0.001) but did not differ between groups in the oviduct. The PTGS2 was localized only in the endometrial and oviductal epithelium and its expression was reduced in cats with CL (p = 0.001). In the endometrial epithelium, PGRMC-1 expression was reduced in cats with CL (p < 0.05). Expression of PGRMC-2 was highest in the endometrial epithelium and lowest in the endometrial stroma (p = 0.01) but did not differ between cats with and without CL. In conclusion, progesterone receptor and PTGS2 downregulation in the female cat closely resembles findings in other spontaneously ovulating domestic animal species.

Survey of nuclear progesterone receptor expression in the uterus of the cyclic and pregnant camel (Camelus dromedarius).

Progesterone receptors (PR) are necessary to mediate the biological effects of progesterone and are integral to the regulation of a number of different aspects of reproduction in mammals including ovulation of the oocyte, implantation of the conceptus and maintenance of pregnancy. This study investigated the expression and localization of progesterone receptors in the uterine wall of both pregnant and cyclic (nonpregnant) camels. Uterine tissue samples were collected from healthy animals and processed for routine histological and immunohistochemical staining techniques to reveal nuclear PR. Demonstration of PR was performed by indirect immunohistochemical techniques using monoclonal antibodies raised against human PR. Immunolocalization of PR was more intense in all four endometrial zones (I-IV) as well as the myometrium of non pregnant (cyclic) animals (animals with newly formed corpus luteum). In contrast, PR immunostaining in both the endometrium and the myometrium was greatly reduced in pregnancy, particularly in the latest stage examined (approximately 366days of gestation). In conclusion, a better understanding of the expression of steroid hormones and their receptors, including progesterone and the PR is critical to improving the reproductive health and pregnancy in the domesticated dromedary camel.

193 PROGESTERONE CONCENTRATIONS AND MESSENGER RNA EXPRESSION OF PROGESTERONE RECEPTORS IN ENDOMETRIAL TISSUE OF BOVINE UTERINE HORN IPSILATERAL AND CONTRALATERAL TO CORPUS LUTEUM

Generally, conception is established in the uterine horn ipsilateral to the corpus luteum (CL) in cattle. When a bovine embryo is transferred into the uterine horn contralateral to CL, conception rate is low. Since progesterone (P4) is essential for the establishment of pregnancy in cattle, locational effects of P4 released from CL at the uterus may cause the differences in fertility. The aim of this study was to determine the endometrial tissue P4 concentrations (EndP4) and the mRNA expression of nuclear progesterone receptor (PGR), and progesterone receptor component-1 (PGRMC-1) and -2 (PGRMC-2) in the endometrial tissues from the ipsi- and contralateral horn. The uteruses of Holstein cows were obtained at a local abattoir. Endometrial tissues were collected from both horns. Based on ovarian morphology, the oestrus cycle of the cow was estimated as follows: early luteal phase (ELP, Day 5–6, Day 0 = oestrus), mid luteal phase (MLP, Day 8–12), late luteal phase (LLP, Day 15–17), and follicular phase (FP, Day 18–20). EndP4 was measured by enzyme immunoassay. Expressions of mRNA were analysed by real-time RT–PCR. Two-way factorial ANOVA and the Steel-Dwass test were applied for a multiple comparison of means. The interrelations between both parameters were expressed by Spearman correlation coefficient. At ELP and MLP, EndP4 in ipsi-horn were higher than that in contra-horn (P &lt; 0.05, see Table 1). Higher mRNA expression of PGRMC-1 in ipsi-horn was observed at ELP compared with contra-horn (P &lt; 0.05). Expressions of mRNA for PGR and PGRMC-2 were similar in both horns. In ipsi-horn at ELP, EndP4 was positively correlated with PGRMC-1 mRNA (r = 0.87, P &lt; 0.05), but was negatively correlated with PGR mRNA (r = –0.76, P &lt; 0.05). However, in contra-horn, EndP4 has no correlation to mRNA expression of P4 receptors. In conclusion, EndP4 was influenced by the location of CL and stage of oestrus cycle. Higher expression of PGRMC-1 mRNA in endometrial tissue of ipsi-horn at ELP might be up-regulated by higher EndP4. These locational effects of CL on uterus may provide an intrauterine environment suitable for embryo development. Table 1.End P4 and expression of mRNA for P4 receptors in bovine uterine horn1

Amniotic membrane-derived mesenchymal cells and their conditioned media: potential candidates for uterine regenerative therapy in the horse.

Amniotic membrane-derived mesenchymal cells (AMCs) are considered suitable candidates for a variety of cell-based applications. In view of cell therapy application in uterine pathologies, we studied AMCs in comparison to cells isolated from the endometrium of mares at diestrus (EDCs) being the endometrium during diestrus and early pregnancy similar from a hormonal standpoint. In particular, we demonstrated that amnion tissue fragments (AM) shares the same transcriptional profile with endometrial tissue fragments (ED), expressing genes involved in early pregnancy (AbdB-like Hoxa genes), pre-implantantion conceptus development (Erα, PR, PGRMC1 and mPR) and their regulators (Wnt7a, Wnt4a). Soon after the isolation, only AMCs express Wnt4a and Wnt7a. Interestingly, the expression levels of prostaglandin-endoperoxide synthase 2 (PTGS2) were found greater in AM and AMCs than their endometrial counterparts thus confirming the role of AMCs as mediators of inflammation. The expression of nuclear progesterone receptor (PR), membrane-bound intracellular progesterone receptor component 1 (PGRMC1) and membrane-bound intracellular progesterone receptor (mPR), known to lead to improved endometrial receptivity, was maintained in AMCs over 5 passages in vitro when the media was supplemented with progesterone. To further explore the potential of AMCs in endometrial regeneration, their capacity to support resident cell proliferation was assessed by co-culturing them with EDCs in a transwell system or culturing in the presence of AMC-conditioned medium (AMC-CM). A significant increase in EDC proliferation rate exhibited the crucial role of soluble factors as mediators of stem cells action. The present investigation revealed that AMCs, as well as their derived conditioned media, have the potential to improve endometrial cell replenishment when low proliferation is associated to pregnancy failure. These findings make AMCs suitable candidates for the treatment of endometrosis in mares.

Expression of nuclear progesterone receptor and progesterone receptor membrane components 1 and 2 in the oviduct of cyclic and pregnant cows during the post-ovulation period

BackgroundProgesterone (P4) may modulate oviductal functions to promote early embryo development in cattle. In addition to its nuclear receptor (PR), P4 may mediate its actions through P4 receptor membrane component 1 (PGRMC1) and its relative, PGRMC2. Two successive experiments were undertaken to characterise the expression of PR, PGRMC1 and PGRMC2 in the bovine oviduct during the post-ovulation period, and to relate their expression to the presence of an embryo, the proximity of the CL and to the region of the oviduct.MethodsIn the first experiment (Exp. I), whole oviduct sections were collected from Holstein cows at Day 1.5, Day 4 and Day 5 post-ovulation (n = 2 cows per stage). The expression of PR, PGRMC1 and PGRMC2 was studied in the ampulla and isthmus by RT-PCR, western-blot and immunohistochemistry. In Exp. II, oviduct epithelial cells were collected from cyclic and pregnant Charolais cows (n = 4 cows per status) at Day 3.5 post-ovulation and mRNA expression of PR, PGRMC1 and PGRMC2 was examined in the ampulla and isthmus by real-time quantitative PCR.ResultsIn Exp. I, PR, PGRMC1 and PGRMC2 were expressed in all oviduct samples. PGRMC1 was mainly localised in the luminal epithelium whereas PR and PGRMC2 were localised in the epithelium as well as in the muscle and stroma layers of the oviduct. The expression was primarily nuclear for PR, primarily cytoplasmic for PGRMC1 and both nuclear and cytoplasmic for PGRMC2. In Exp. II, mRNA levels for PR, PGRMC1 and PGRMC2 were not affected by either the pregnancy status or the side relative to the CL. However, the expression of PR and PGRMC2 varied significantly with the region of the oviduct: PR was more highly expressed in the isthmus whereas PGRMC2 was more highly expressed in the ampulla.ConclusionsThis is the first evidence of PGRMC2 expression in the bovine oviduct. Our findings suggest that P4 regulates the functions of the bovine oviduct in a region-specific manner and through both classical and non classical pathways during the post-ovulation period.

Modulation of ATP-induced calcium signaling by progesterone in T47D-Y breast cancer cells

Extracellular ATP activates purinergic (P(2)) receptors with an increase in intracellular calcium and phosphorylation of MAPK. In this study we have investigated the effect of progesterone/progestin on ATP-induced calcium mobilization and phosphorylation of the kinase ERK in the T47D-Y breast cancer cell line that exhibits no detectable nuclear progesterone receptor expression. Brief pretreatment with progesterone/progestin results in a dose dependent inhibition of ATP-induced intracellular calcium mobilization, and inhibition of ERK phosphorylation. Response to a cell impermeable ligand and inhibition of the response by an inactivating antibody suggests a mechanism of action at the plasma membrane. These results in T47D-Y cells strongly suggest that progesterone can act in a rapid non-nuclear manner to inhibit extracellular ATP effects on intracellular calcium mobilization and ERK activation. This research provides an example of progesterone action in a breast cancer cell line lacking expression of the classical nuclear progesterone receptors.

Progesterone stimulates mitochondrial activity with subsequent inhibition of apoptosis in MCF-10A benign breast epithelial cells

The effects of progesterone on breast epithelial cells remain poorly defined with observations showing both proliferative and antiproliferative effects. As an example, progesterone levels correlate with increased epithelial cell proliferation, but there is discordance between the dividing cells and the cells with nuclear progesterone receptor expression. The release of paracrine growth factors from nuclear receptor-positive cells has been postulated as a mechanism, since in vitro studies show a lack of growth effect by progesterone in breast epithelial cells lacking nuclear receptors. This study examined possible nongenomic effects of progesterone in breast epithelia by using MCF-10A cells known to lack nuclear progesterone receptor expression. Treatment for 30-60 min with progesterone or the progestin, R5020, increased mitochondrial activity as shown by an increase in mitochondrial membrane potential (hyperpolarization) with a concordant increase in total cellular ATP. The reaction was inhibited by a specific progesterone receptor antagonist and not affected by the translation inhibitor cycloheximide. Progestin treatment inhibited apoptosis induced by activation of the FasL pathway, as shown by a decrease in sub-G(1) cell fraction during fluorescence-activated cell sorting and a decrease in caspase 3/7 levels. Progestin treatment did not alter the cell cycle over 48 h. Our study demonstrates a nongenomic action of progesterone on benign breast epithelial cells, resulting in enhanced cellular respiration and protection from apoptosis.

Nuclear Progesterone Receptor Expression in the Human Fetal Membranes and Decidua at Term Before and After Labor

To explore how progesterone affects human pregnancy, we identified the progesterone target cells within the fetal membranes (amnion, chorion, and decidua) at term by assessing the extent of expression and localization of the nuclear progesterone receptors, progesterone receptor-A and progesterone receptor-B. Fetal membranes (separated into amnion and chorion-decidua) were obtained after term cesarean deliveries performed before (n = 7) and after (n = 7) labor onset. Nuclear progesterone receptor expression was determined by the abundance of nuclear progesterone receptor mRNAs (by quantitative reverse transcriptase-polymerase chain reaction) and proteins (by western blotting). Localization of nPRs was determined by immunohistochemistry. Progesterone receptor-A and progesterone receptor-B mRNA and protein levels were highest in the chorion-decidua and did not change in association with labor. Nuclear progesterone receptor mRNAs and proteins were barely detectable in amnion. Nuclear progesterone receptor immunostaining was detected only in the nucleus of decidual cells. These findings suggest that the decidua, and not the amnion and chorion, is a direct target for nuclear progesterone receptor-mediated progesterone actions during human pregnancy.

Receptor Isoforms That Mediate Estrogen and Progestagen Action in the Female Lower Urinary Tract

Bladder symptoms can be ameliorated by sex steroids but to our knowledge the mechanism of action is unknown. Previous studies of steroid receptor expression in the bladder did not indicate receptor subtype expression. We report the distribution of estrogen and progesterone receptor isoforms in the female lower urinary tract. Prospectively recruited women undergoing routine urogynecological or gynecological surgery provided cold cup biopsy samples from the bladder dome, trigone, and proximal and distal urethra. The samples were immediately frozen or fixed in formalin. After RNA extraction transcripts for estrogen receptor alpha and beta, and progesterone receptor A and B were noted on reverse transcriptase-polymerase chain reaction using isoform specific primers. The precise cellular localization of receptor proteins and their relative levels were assessed by immunochemistry in formalin fixed tissue sections with isoform specific antibodies. Nine premenopausal and 10 postmenopausal women were recruited into the study. Two postmenopausal women on hormone replacement therapy. Estrogen receptor alpha and beta, and progesterone receptor A and B transcripts were detected in whole bladder extracts. Nuclear estrogen receptor alpha immunoreactivity was present in squamous epithelium but absent from transitional epithelium. Estrogen receptor beta immunoreactivity was expressed in squamous and transitional cell epithelium. Nuclear progesterone receptor expression was present in urethral squamous epithelium only. Progesterone receptor expression was greater in premenopausal women and in postmenopausal women on estrogen. Estrogen receptor alpha and beta genes are transcribed in bladder tissue but only estrogen receptor beta is translated into protein, suggesting that the urothelium responds to endogenous estrogen via estrogen receptor beta. Progesterone receptor expression is confined to urethral squamous epithelium and the major isoform is progesterone receptor A.