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Regulation of the estrogen receptor and its messenger ribonucleic acid in the ovariectomized sheep myometrium and endometrium: the role of estradiol and progesterone. Wu W X,Owiny J,Zhang Q,Ma X H,Nathanielsz P W Biology of reproduction Estrogen receptor (ER) mRNA is dramatically increased in sheep myometrium and endometrium during glucocorticoid-induced premature labor and term spontaneous labor. However, the underlying mechanism for the up-regulation of uterine ER in labor is still unknown. We used ovariectomized (OVX) non-pregnant sheep to analyze the role of estradiol and progesterone in the regulation of myometrial and endometrial ER protein and ER mRNA in vivo. Twenty-one OVX ewes were treated with saline (n = 6), or with estradiol infused i.v. for 2 days (50 micrograms/day, n = 5), or with an intravaginal progesterone sponge for 10 days (containing 0.3 g progesterone, n = 5), or with an intravaginal progesterone sponge for 10 days with estradiol (50 micrograms/day) administered on Days 9 and 10 with the progesterone sponge still in place (n = 5). The ER protein concentration in both cytosolic and nuclear compartments, analyzed by Western blot, increased significantly (P < 0.05) in the myometrium after estradiol treatment, while progesterone alone had no detectable effect on ER level. Elevated ER protein was observed only in the nuclear fraction of endometrium. However, when estradiol was given together with progesterone treatment, progesterone antagonized the up-regulatory effect of estradiol on the ER level both at the endometrium and myometrium. The changes in cellular ER mRNA followed the pattern observed at the ER protein level. Estrogen receptor mRNA was elevated significantly (p < 0.01) only in estradiol-treated ewes. Expression of the ER gene in ewes receiving progesterone alone or progesterone combined with estradiol was similar to that of the control group. From these observations we conclude that ER gene expression and active ER synthesis in nonpregnant sheep myometrium and endometrium are estradiol-dependent. Progesterone antagonizes this estrogen action. Progesterone down-regulated the elevated ER mRNA when used together with estradiol. In situ hybridization showed that ER mRNA was evenly distributed in the smooth muscle cells and blood vessels of the myometrium and the epithelial cells of the glands in endometrium. In conclusion, we have observed estradiol-dependent activation of ER gene expression as well as active ER synthesis in the nonpregnant sheep myometrium and endometrium. Progesterone acted as an antagonist of estradiol on ER gene expression. 10.1095/biolreprod55.4.762
Influence of oestrogen and progesterone on macrophage distribution in the mouse uterus. De M,Wood G W The Journal of endocrinology Macrophages are constituents of all normal connective tissue including the murine uterus. Macrophages have been identified previously in endometrium and myometrium of pregnant and non-pregnant murine uterus using antibodies against macrophages. In the current study immunohistochemical analysis of murine uterus demonstrated that there were not significant quantitative differences in uterine macrophages between the diestrous, pro-oestrous and oestrous stages. However, distributional changes occurred during the oestrous cycle. Macrophages were evenly distributed throughout uterine tissue during dioestrus, while, during pro-oestrus and oestrus, their concentration was highest in the subepithelial stroma. Because the oestrous cycle is hormonally regulated, we asked whether or not oestrogen and/or progesterone might influence macrophage distribution. Ovariectomy, which eliminates cyclical production of oestrogen and progesterone, resulted in a significant decrease in both the relative and the absolute number of uterine macrophages within 6 days. Injections of progesterone or oestrogen to ovariectomized mice resulted in restoration of uterine macrophage numbers. Injection of oestrogen plus progesterone in a regimen known to prepare the uterus for receptivity for blastocyst implantation increased the number of macrophages to levels which were consistently higher than those seen during oestrus. Moreover, following hormone administration macrophages were more concentrated in the subepithelial stroma, a distributional pattern which was most evident following injection of both hormones. The results suggest that both oestrogen and progesterone promote quantitative and distributional changes in the uterine macrophage population. 10.1677/joe.0.1260417
Estrogen receptor (ER) expression and function in the pregnant human myometrium: estradiol via ERα activates ERK1/2 signaling in term myometrium. Welsh Toni,Johnson Matrika,Yi Lijuan,Tan Huiqing,Rahman Roksana,Merlino Amy,Zakar Tamas,Mesiano Sam The Journal of endocrinology Estrogens are thought to promote labor by increasing the expression of pro-contraction genes in myometrial cells. The specific estrogen receptors ((ERs: ERα and ERβ (also known as ESR1 and ESR2)) and G protein-coupled receptor 30 (GPR30; also known as G protein-coupled estrogen receptor 1)) and signaling pathways that mediate these actions are not clearly understood. In this study, we identified the ERs expressed in the pregnant human myometrium and determined a key extranuclear signaling pathway through which estradiol (E(2)) modulates expression of the gene encoding the oxytocin receptor (OXTR), a major pro-contraction protein. Using quantitative RT-PCR, we found that ERα and GPR30 mRNAs were expressed in the human pregnant myometrium while ERβ mRNA was virtually undetectable. While mRNA encoding ERα was the predominant ER transcript in the pregnant myometrium, ERα protein was largely undetectable in myometrial tissue by immunoblotting. Pharmacological inhibition of 26S proteasome activity increased ERα protein abundance to detectable levels in term myometrial explants, however, indicating rapid turnover of ERα protein by proteasomal processing in the pregnant myometrium. E(2) stimulated rapid extranuclear signaling in myometrial explants, as evidenced by increased extracellularly regulated kinase (ERK1/2) phosphorylation within 10 min. This effect was inhibited by pre-treatment with an ER antagonist, ICI 182 780, indicating the involvement of ERα. Inhibition of ERK signaling abrogated the ability of E(2) to stimulate OXTR gene expression in myometrial explants. We conclude that estrogenic actions in the human myometrium during pregnancy, including the stimulation of contraction-associated gene expression, can be mediated by extranuclear signaling through ERα via activation of the ERK/mitogen-activated protein kinase pathway. 10.1530/JOE-11-0358
Ghrelin in the human myometrium. O'Brien Margaret,Earley Padraig,Morrison John J,Smith Terry J Reproductive biology and endocrinology : RB&E BACKGROUND:Ghrelin is a 28-amino acid octanolyated peptide, synthesised primarily in the stomach. It stimulates growth hormone release, food intake and exhibits many other diverse effects. Our group have previously determined that ghrelin inhibited human contractility in vitro. The aim of this study therefore, was to investigate the expression of ghrelin, its receptor, the growth hormone secretagogue receptor type 1 (GHS-R1), ghrelin O-acyltransferase (GOAT) which catalyses ghrelin octanoylation, prohormone convertase 1/3 (PC1/3) responsible for pro-ghrelin processing, in human myometrium, during pregnancy prior to labour, during labour and in the non-pregnant state. Modulation of ghrelin and ghrelin receptor expression in cultured myometrial cells was also investigated. METHODS:mRNA and protein were isolated from human myometrium and the myometrial smooth muscle cell line hTERT-HM; and real-time fluorescence RT-PCR, western blotting and fluorescence microscopy performed. The effects of beta-Estradiol and bacterial lipopolysaccharide (LPS) on hTERT-HM gene expression were evaluated by western blotting. RESULTS:We have reported for the first time the expression and processing of ghrelin, GHS-R1, GOAT and PC1/3 expression in human myometrium, and also the down-regulation of ghrelin mRNA and protein expression during labour. Furthermore, GHS-R1 protein expression significantly decreased at labour. Myometrial GOAT expression significantly increased during term non-labouring pregnancy in comparison to both non-pregnant and labouring myometrium. Mature PC1/3 protein expression was significantly decreased at term pregnancy and labour in comparison to non-pregnant myometrium. Ghrelin, GHS-R1, GOAT and PC1/3 mRNA and protein expression was also detected in the hTERT-HM cells. Ghrelin protein expression decreased upon LPS treatment in these cells while beta-Estradiol treatment increased GHS-R1 expression. CONCLUSIONS:Ghrelin processing occurred in the human myometrium at term pregnancy and in the non-pregnant state. GOAT expression which increased during term non-labouring pregnancy demonstrating a similar expression pattern to prepro-ghrelin and GHS-R1, decreased at labour, signifying possible myometrial ghrelin acylation. Moreover, the presence of PC1/3 may contribute to pro-ghrelin processing. These results along with the previous in vitro data suggest that myometrially-produced and processed ghrelin plays a significant autocrine or paracrine role in the maintenance of relaxation in this tissue during pregnancy. Furthermore, the significant uterine modulators LPS and beta-Estradiol are involved in the regulation of ghrelin and ghrelin receptor expression respectively, in the human myometrium. 10.1186/1477-7827-8-55
Collagen and elastic fiber remodeling in the pregnant mouse myometrium†. Biology of reproduction The myometrium undergoes progressive tissue remodeling from early to late pregnancy to support fetal growth and transitions to the contractile phase to deliver a baby at term. Much of our effort has been focused on understanding the functional role of myometrial smooth muscle cells, but the role of extracellular matrix is not clear. This study was aimed to demonstrate the expression profile of sub-sets of genes involved in the synthesis, processing, and assembly of collagen and elastic fibers, their structural remodeling during pregnancy, and hormonal regulation. Myometrial tissues were isolated from non-pregnant and pregnant mice to analyze gene expression and protein levels of components of collagen and elastic fibers. Second harmonic generation imaging was used to examine the morphology of collagen and elastic fibers. Gene and protein expressions of collagen and elastin were induced very early in pregnancy. Further, the gene expressions of some of the factors involved in the synthesis, processing, and assembly of collagen and elastic fibers were differentially expressed in the pregnant mouse myometrium. Our imaging analysis demonstrated that the collagen and elastic fibers undergo structural reorganization from early to late pregnancy. Collagen and elastin were differentially induced in response to estrogen and progesterone in the myometrium of ovariectomized mice. Collagen was induced by both estrogen and progesterone. By contrast, estrogen induced elastin, but progesterone suppressed its expression. The current study suggests progressive extracellular matrix remodeling and its potential role in the myometrial tissue mechanical function during pregnancy and parturition. 10.1093/biolre/ioac102
Pregnancy-promoting actions of HCG in human myometrium and fetal membranes. Ticconi C,Zicari A,Belmonte A,Realacci M,Rao Ch V,Piccione E Placenta Human chorionic gonadotropin (HCG) plays a major role in early human development through a series of well recognized pregnancy-promoting actions that are exerted in the first trimester, including maternal recognition of pregnancy, enhancement of embryo implantation and survival, stimulation of trophoblast growth and differentiation, and prolongation of the functional life of the corpus luteum. Recent research indicates that HCG can exert significant pregnancy-promoting actions also in the remainder of pregnancy through its effect on the myometrium and on fetal membranes. In the myometrium, HCG promotes the inhibition of smooth muscle cell contractility through several mechanisms, including inhibition of gap junction formation, reduction of intracellular calcium concentration, increase in the expression of progesterone receptor, and an increase in the expression of phosphodiesterase 5 (PDE5), an enzyme controlling the intracellular levels of cGMP. This effect appears to be specific for PDE5 since it has not been found for other hormones potentially involved in pregnancy such as estrogen, progesterone and thyroid hormone. In fetal membranes, HCG can modulate expression of the inducible isoform of nitric oxide synthase (iNOS), as well as specific immunoregulatory cytokines such as the high mobility group box 1 (HMGB1) protein. This accumulating evidence suggests that HCG has a wide spread pregnancy-promoting actions that are exerted in various reproductive and gestational tissues. 10.1016/j.placenta.2007.01.002
Secretion of estradiol-17beta by porcine endometrium and myometrium during early pregnancy and luteolysis. Franczak A,Kotwica G Theriogenology Past studies of the source of estrogens secreted during maternal recognition of pregnancy in pigs have focused on embryonic rather than uterine origin of these steroids. The present study documents: (1) the expression of the gene CYP 17, encoding cytochrome P450 17alpha-hydroxylase/C(17-20) lyase and (2) the synthesis and secretion of estradiol-17 beta (E(2)) in endometrial and myometrial tissues in gilts. The expression of CYP 17 gene was shown in porcine endometrium and myometrium. Basal endometrial secretion of E(2) was higher in pregnant gilts than in cyclic gilts (days 14-16). The myometrium secreted more E(2) during the expected time of luteolysis compared to early pregnancy. Basal secretion of E(2) during pregnancy was higher from the endometrium than from the myometrium. Conversely, during luteolysis E(2) secretion was higher from the myometrium and lower from the endometrium. In pregnant and cyclic gilts (days 14-16), progesterone (P(4), 10(-5)M) in vitro significantly increased E(2) secretion regardless of reproductive status. Oxytocin (OT, 10(-7)M) had no influence on E(2) secretion and did not change the stimulatory effect of P(4) in both tissues examined. In conclusions: (1) the CYP 17 gene transcript is present in porcine endometrium and myometrium; (2) porcine endometrium and myometrium release E(2) in vitro; (3) the endometrium releases more E(2) than the myometrium during early pregnancy; (4) the myometrium releases E(2) mainly during luteolysis; (5) the endometrium and myometrium can increase E(2) release in vitro if substrate (P(4)) is provided during early pregnancy and luteolysis. These data suggest active estrogen production by the myometrium and endometrium as an alternative source for this signal for recognition of pregnancy in the pig. 10.1016/j.theriogenology.2007.09.023
Oestrogen-dependent expression of the SM2 smooth muscle-type myosin isoform in rabbit myometrium. Journal of muscle research and cell motility Ovarectomized rabbits displayed a decreased SM1 to SM2 ratio of smooth muscle-type myosin heavy chain isoforms compared to unoperated, virgin females which was reversed after 17beta-oestradiol administration to a value similar to that of control animals. When this steroid was given to sexually immature animals or to adult virgin rabbits, SM2 expression was not induced, as also happened with proliferating myometrial smooth muscle cells grown in vitro. In growing rabbit, the 17beta-oestradiol administration induced the formation of the circular and the longitudinal muscle layers, characteristics of sexually competent females. The SM2 isoform was up-regulated during postnatal development and the SM1 to SM2 ratio changed during pregnancy and post-partum period but not with human gonadotropin treatment which increases the level of circulating progesterone. Immunofluorescence staining of adult myometrium with anti-SM2 antibody indicated that this isoform is localized to the longitudinal layer exclusively and, in contrast to the circular layer, its expression was independent of oestrogen level. Difference in oestrogen sensitivity between the two layers was also detected for the expression of the intermediate filament protein vimentin and the thin filament protein calponin. Changes of SM2 expression in the myometrium correlated with variations in the oestrogen receptor density as also confirmed by decreased SM2 content/oestrogen receptor density in the circular layer when ovarectomized females were treated with the oestrogen antagonist ICI 182,780. Our results indicate that: (1) a specific distribution of myosin heavy chain exists within rabbit myometrium, and (2) SM2 myosin expression in this smooth muscle is under oestrogen control. 10.1023/a:1018642713934
Estrogen action: induction of the synthesis of a specific protein (IP) in the myometrium, the stroma and the luminal epithelium of the rat uterus. Dupont-Mairesse N,Galand P Endocrinology The effect of estrogen on the synthesis of a specific uterine protein (estrogen-induced protein=IP) was investigated at the level of the epithelial, stromal and myometrial tissue fractions. For measuring IP induction, the procedure of Katzenellenbogen and Gorski was followed exactly (involving co-electrophoresis of soluble protein extracts from 3H-labeled estrogen treated uteri and 14C-labeled controls) except for the fact that the uteri were fractionated into their three main tissue components before homogenization. The results show that induction of IP synthesis by estradiol takes place in the three tissue fractions considered. This is consistent with hypotheses assuming a key function for IP in the development of the full estrogenic response in the uterus. 10.1210/endo-96-6-1587