Developmental biology of uterine glands

Select nutrients in the ovine uterine lumen. VI. Expression of FK506-binding protein 12-rapamycin complex-associated protein 1 (FRAP1) and regulators and effectors of mTORC1 and mTORC2 complexes in ovine uteri and conceptuses

FRAP1 (FK506-binding protein 12-rapamycin complex-associated protein 1), a component of the nutrient-sensing cell signaling pathway, is critical for cell growth and metabolism. The present study determined expression of FRAP1 and associated members of the mTORC1 and mTORC2 cell signaling pathways in uteri of cyclic and pregnant ewes and conceptuses, as well as effects of pregnancy, progesterone (P4), and interferon tau (IFNT) on their expression. The mRNAs for FRAP1, LST8, MAPKAP1, RAPTOR, RICTOR, TSC1, TSC2, RHEB, and EIF4EBP1 were localized to luminal, superficial glandular, and glandular epithelia and stromal cells of uteri from cyclic and pregnant ewes, as well as trophectoderm and endoderm of conceptuses between Days 13 and 18 of pregnancy. The abundance of FRAP1, RAPTOR, RICTOR, TSC1, and TSC2 mRNAs in endometria was unaffected by pregnancy status or by day of the estrous cycle or pregnancy; however, levels of LST8, MAPKAP1, RHEB, and EIF4EBP1 mRNA increased in endometria during early pregnancy. In ovariectomized ewes, P4 and IFNT stimulated expression of RHEB and EIF4EBP1 in uterine endometria. Total endometrial FRAP1 protein and phosphorylated FRAP1 protein levels were affected by pregnancy status and by day after onset of estrus, and phosphorylated FRAP1 protein was detected in nuclei of uterine epithelia and conceptuses. In endometria of pregnant ewes, increases in abundance of mRNAs for RICTOR, RHEB, and EIF4EBP1, as well as RHEB protein, correlated with rapid conceptus growth and development during the peri-implantation period. These results suggest that the FRAP1 cell signaling pathway mediates interactions between the maternal uterus and peri-implantation conceptuses and that P4 and IFNT affect this pathway by regulating expression of RHEB and EIF4EBP1.

Expression of transcriptional repressor Slug gene in mouse endometrium and its effect during embryo implantation

Slug, a member of the Snail family of zinc-finger transcription factors, is involved in regulating embryonic development and tumorigenesis. The aim of this study was to investigate the expression of Slug in mouse endometrium during early pregnancy and its possible role during embryo implantation. Fluorescence quantitative polymerase chain reaction and immunohistochemistry were applied to detect Slug mRNA and Slug protein expression in endometrium of nonpregnant and early pregnant mice, respectively. The expressions of Slug mRNA and its protein in pregnant group were higher than that in nonpregnant group and gradually increased from pregnancy day 1, reaching its maximum level on day 4 and then declining on days 5, 6, and 7. Immunohistochemistry showed that Slug protein was mainly present in luminal epithelium from pregnancy days 2 to 5 and in glandular epithelium from days 2 to 6 and enhanced significantly in stromal cells on days 4, 5, and 6. The number of embryos implanted was greatly decreased after Slug function in mouse endometrium was blocked by the intrauterine injection with anti-Slug polyclonal antibody on day 3 of pregnancy before implantation. These results suggested that up-regulation of Slug expression may play a key role in the embryo implantation in mice.

Exposure to developing females induces polyuria, polydipsia, and altered urinary levels of creatinine, 17beta-estradiol, and testosterone in adult male mice (Mus musculus)

Novel male mice can accelerate reproductive maturation in proximal developing females, an effect mediated by the chemistry of the males' urine. Exogenous estrogens can similarly accelerate female sexual development. In Experiment 1, adult male mice were housed across wire grid from either empty compartments or those containing post-weanling females. Proximity of females caused males to urinate more, progressively over days of exposure, with most urination directed towards females' compartments. Male urine collected after 5 days in these conditions was analyzed by enzyme immunoassay for 17beta-estradiol, testosterone, and creatinine. Urinary creatinine of isolated males significantly exceeded that of female-exposed males. Unadjusted urinary steroids also trended toward higher levels in isolates, but creatinine-adjusted estradiol and testosterone of female-exposed males significantly exceeded that of isolated males. In Experiment 2, measurement of water consumption indicated significantly greater drinking by female-exposed as opposed to isolated males. In Experiment 3, males were housed in isolation or beside post-weanling intact (sham-operated) females, ovariectomized females, or intact (sham-operated) males. Male water consumption was elevated in all conditions involving social contact. Urinary creatinine was significantly lower in female-exposed males compared to isolated controls, while unadjusted testosterone was significantly lower in males in all social conditions. Again, creatinine-adjusted estradiol in female-exposed males significantly exceeded that of isolates. These data indicate that adult males drink and urinate more, have more dilute urine, and have a higher ratio of estradiol to creatinine when they are near developing females. These dynamics increase females' exposure to urinary steroids and other urinary constituents that can hasten sexual maturity.

A review of uterine structural modifications that influence conceptus implantation and development in sheep and goats

Evolution of the placenta and viviparity in eutherian animals underscores the need for an intimate relationship between the developing conceptus (embryo/foetus and associated extra-embryonic membranes) and the dam throughout the period of pregnancy. Thus, maternal support is unequivocally important for conceptus survival and development in utero. Under the influence of several pregnancy-associated hormones, the maternal uterine architecture undergoes rapid growth and substantial remodeling early in gestation. These changes are necessary preparations to accommodate and support rapid conceptus development and growth in the later two-thirds of pregnancy. There are species variations in the nature and extent of uterine remodeling during pregnancy. The regulatory influence of these uterine wall modifications on conceptus survival, implantation and placentation in sheep and goats are discussed in this review.

Epigenetic programming of porcine endometrial function and the lactocrine hypothesis

Epigenetic programs controlling development of the female reproductive tract (FRT) are influenced by the effects of naturally occurring bioactive agents on patterns of gene expression in FRT tissues during organizationally critical periods of foetal and perinatal life. Aberrations in such important cellular and molecular events, as may occur with exposure to natural or manmade steroid or peptide receptor-modulating agents, disrupt the developmental program and can change the developmental trajectory of FRT tissues, including the endometrium, with lasting consequences. In the pig, as in other mammals, maternal programming of FRT development begins pre-natally and is completed post-natally, when maternal effects on development can be communicated via signals transmitted in milk. Studies involving relaxin (RLX), a prototypic milk-borne morphoregulatory factor (MbF), serve as the basis for ongoing efforts to identify maternal programming events that affect uterine and cervical tissues in the neonatal pig. Data support the lactocrine hypothesis for delivery of MbFs to neonates as a specific consequence of nursing. Components of a maternally driven lactocrine mechanism for RLX-mediated signalling in neonatal FRT tissues, including evidence that milk-borne RLX is delivered into the neonatal circulation where it can act on RLX receptor (RXFP1)-positive neonatal tissues to affect their development, are in place in the pig. The fact that all newborn mammals drink milk extends the timeframe of maternal influence on neonatal development across many species. Thus, lactocrine transmission of milk-borne developmental signals is an element of the maternal epigenetic programming equation that deserves further study.

Female reproductive disorders: the roles of endocrine-disrupting compounds and developmental timing

OBJECTIVE

To evaluate the possible role of endocrine-disrupting compounds (EDCs) on female reproductive disorders emphasizing developmental plasticity and the complexity of endocrine-dependent ontogeny of reproductive organs. Declining conception rates and the high incidence of female reproductive disruptions warrant evaluation of the impact of EDCs on female reproductive health.

DESIGN

Publications related to the contribution of EDCs to disorders of the ovary (aneuploidy, polycystic ovary syndrome, and altered cyclicity), uterus (endometriosis, uterine fibroids, fetal growth restriction, and pregnancy loss), breast (breast cancer, reduced duration of lactation), and pubertal timing were identified, reviewed, and summarized at a workshop.

CONCLUSION(S)

The data reviewed illustrate that EDCs contribute to numerous human female reproductive disorders and emphasize the sensitivity of early life-stage exposures. Many research gaps are identified that limit full understanding of the contribution of EDCs to female reproductive problems. Moreover, there is an urgent need to reduce the incidence of these reproductive disorders, which can be addressed by correlative studies on early life exposure and adult reproductive dysfunction together with tools to assess the specific exposures and methods to block their effects. This review of the EDC literature as it relates to female health provides an important platform on which women's health can be improved.

Progesterone and placentation increase secreted phosphoprotein one (SPP1 or osteopontin) in uterine glands and stroma for histotrophic and hematotrophic support of ovine pregnancy

Secreted phosphoprotein one (SPP1, osteopontin) may regulate conceptus implantation and placentation. We investigated effects of progesterone (P(4)) and the conceptus on expression and localization of SPP1 in the ovine uterus. Steady-state levels of SPP1 mRNA in the endometrium of unilaterally pregnant ewes did not differ significantly between nongravid and gravid horns within their respective days of pregnancy; however, levels did increase as pregnancy progressed. SPP1 mRNA was detectable in the glandular epithelium (GE) of both nongravid and gravid horns via in situ hybridization. SPP1 protein was localized to the apical surface of the luminal epithelium of both nongravid and gravid uterine horns. Gravid horns exhibited extensive stromal SPP1 on Days 40 through 120, whereas SPP1 was markedly lower in the stroma of nongravid uterine horns through Day 80 of pregnancy. By Day 120, stromal expression of SPP1 between nongravid and gravid horns was similar. Long-term P(4) treatment of ovariectomized ewes induced SPP1 in the uterine stroma and GE. A bioactive 45-kDa SPP1 fragment was purified from uterine secretions and promoted ovine trophectoderm cell attachment in vitro. Interestingly, increased stromal cell expression of SPP1 was positively associated with vascularization as assessed by von Willebrand factor staining. Finally, ovine uterine artery endothelial cells produced SPP1 during outgrowth into three-dimensional collagen matrices in an in vitro model system that recapitulates angiogenesis. Collectively, P(4) induces and the conceptus further stimulates SPP1 in uterine GE and stroma, where SPP1 likely influences histotrophic and hematotrophic support of conceptus development.

Insulin-like growth factor II activates phosphatidylinositol 3-kinase-protooncogenic protein kinase 1 and mitogen-activated protein kinase cell Signaling pathways, and stimulates migration of ovine trophectoderm cells

IGF-II, a potent stimulator of cellular proliferation, differentiation, and development, regulates uterine function and conceptus growth in several species. In situ hybridization analyses found that IGF-II mRNA was most abundant in the caruncular endometrial stroma of both cyclical and pregnant ewes. In the intercaruncular endometrium, IGF-II mRNA transitioned from stroma to luminal epithelium between d 14 and 20 of pregnancy. IGF-II mRNA was present in all cells of the conceptus but was particularly abundant in the yolk sac. Immunohistochemical analyses revealed that phosphorylated (p)-protooncogenic protein kinase 1, p-ribosomal protein S6 kinase, p-ERK1/2, and p-P38 MAPK proteins were present at low levels in a majority of endometrial cells but were most abundant in the nuclei of endometrial luminal epithelium and conceptus trophectoderm of pregnant ewes. In mononuclear trophectoderm cells isolated from d-15 conceptuses, IGF-II increased the abundance of p-pyruvate dehydrogenase kinase 1, p-protooncogenic protein kinase 1, p-glycogen synthase kinase 3B, p-FK506 binding protein 12-rapamycin associated protein 1, and p-ribosomal protein S6 kinase protein within 15 min, and the increase was maintained for 90 min. IGF-II also elicited a rapid increase in p-ERK1/2 and p-P38 MAPK proteins that was maximal at 15 or 30 min posttreatment. Moreover, IGF-II increased migration of trophectoderm cells. Collectively, these results support the hypothesis that IGF-II coordinately activates multiple cell signaling pathways critical to survival, growth, and differentiation of the ovine conceptus during early pregnancy.

Postnatal uterine development in Inverdale ewe lambs

Postnatal development of the uterus involves, particularly, development of uterine glands. Studies with ovariectomized ewe lambs demonstrated a role for ovaries in uterine growth and endometrial gland development between postnatal days (PNDs) 14 and 56. The uterotrophic ovarian factor(s) is presumably derived from the large numbers of growing follicles in the neonatal ovary present after PND 14. The Inverdale gene mutation (FecXI) results in an increased ovulation rate in heterozygous ewes; however, homozygous ewes (II) are infertile and have 'streak' ovaries that lack normal developing of preantral and antral follicles. Uteri were obtained on PND 56 to determine whether postnatal uterine development differs between wild-type (++) and II Inverdale ewes. When compared with wild-type ewes, uterine weight of II ewes was 52% lower, and uterine horn length tended to be shorter, resulting in a 68% reduction in uterine weight:length ratio in II ewes. Histomorphometrical analyses determined that endometria and myometria of II ewes were thinner and intercaruncular endometrium contained 38% fewer endometrial glands. Concentrations of estradiol in the neonatal ewes were low and not different between ++ and II ewes, but II ewes had lower concentrations of testosterone and inhibin-alpha between PNDs 14 and 56. Receptors for androgen and activin were detected in the neonatal uteri of both ++ and II ewes. These results support the concept that developing preantral and/or antral follicles of the ovary secrete uterotrophic factors, perhaps testosterone or inhibin-alpha, that acts in an endocrine manner to stimulate uterine growth and endometrial gland development in the neonatal ewes.

Distribution of androgen receptor in the porcine uterus throughout pregnancy

The uterus is a well-known target of endocrine, paracrine and autocrine acting molecules among which steroid hormones (oestrogens, androgens and progesterone) are of special importance. The uterine tissues (endometrium and myometrium) undergo morphological and physiological changes which are associated with changes in expression of steroid hormone receptors. Androgen receptors (AR) that mediate the action of androgens have already been detected in porcine uteri during the oestrous cycle and early pregnancy. To evaluate the role of AR in uterine physiology, the presence of ARmRNA and AR protein localization in the porcine uterus from day 10 to day 90 of pregnancy and in the uterus from the foetus of day 90 postcoitum (p.c.) and from the neonatal 1-day-old piglet was studied. ARmRNA was detected in the porcine endometrium up to day 18 p.c., while AR protein was detectable in glandular epithelium and stromal cells as through day 90 of pregnancy. AR was also detected in the myometrium on all investigated days of pregnancy; however, on day 90, the immunostaining was present only in a limited number of cells. AR immunostaining was clearly demonstrated in the uterus of the female foetuses on day 90 as well as in the uterus of 1-day-old piglets. The physiological relevance of this finding needs further elucidation.

The onset of puberty in female mice as reflected in urinary steroids and uterine/ovarian mass: interactions of exposure to males, phyto-oestrogen content of diet, and ano-genital distance

Development of puberty in female mice was examined in relationship with the ano-genital distance index (AGDI), phyto-oestrogen content of diet and exposure to males post weaning. Throughout gestation and post-natal development, females were exposed to a regular diet or a nutritionally similar diet deficient in phyto-oestrogens. After segregation at weaning on the basis of short or long AGDI, an indirect measure ofin uteroandrogen exposure, females were housed alone or underneath two outbred adult males for 2 weeks. Female urinary samples were collected non-invasively throughout this exposure, then assayed for oestradiol, progesterone and creatinine. Females were then killed and uterine and ovarian mass was determined. Urinary oestradiol was substantially reduced in females raised on the phyto-oestrogen-free diet. Oestradiol levels were more dynamic over days in urine of male-exposed females, especially among those on the regular diet. Urinary progesterone was not strongly influenced by diet. Progesterone was more dynamic in urine of male-exposed females, and was generally elevated compared with levels in isolated females, the size of this effect dependent on AGDI, diet and whether the measure was adjusted for creatinine. Urinary creatinine was elevated by the phyto-oestrogen-free diet and reduced by male exposure, tending to decline over days in females exposed to males. Male exposure increased uterine and ovarian mass and was influenced by AGDI in interaction with diet and male exposure.

Traffic of endogenous, transduced, and endocytosed prolactin in rabbit lacrimal acinar cells

The rabbit lacrimal gland undergoes an immunophysiological transformation during pregnancy, reminiscent of that of the mammary gland as it prepares to deliver secretory IgA into the nascent fluid product. The contents of TGF-beta and prolactin (PRL) within ductal epithelial cells increase, and their primary localizations shift from the apical to the basal cytoplasm, suggesting a transformation from exocrine to paracrine secretion. Studies with ex vivo acinar cell models demonstrated that elevated PRL suppresses traffic of secretory proteins into the regulated exocrine apparatus and directs them into a novel, induced, regulated paracrine apparatus [Wang, Y., Chiu, C.T., Nakamura, T., Walker, A.M., Petridou, B., Trousdale M.D., Hamm-Alvarez S.F., Schechter J.E., Mircheff A.K., 2007. Elevated prolactin redirects secretory vesicle traffic in rabbit lacrimal acinar cells. Am. J. Physiol. Endocrinol. Metab. 292, E1122-E1134]. However, it was not clear whether PRL itself entered the induced paracrine apparatus. In the present study, confocal immunofluorescence microscopy revealed that natively expressed PRL and over-expressed PRL co-localized with PRL receptors (PRLR); rab11, a marker for the recycling endosome; gamma-adaptin, a marker for the Golgi complex and trans-Golgi network; and rab7, a marker for the autophagic lysosomal apparatus. Natively expressed, over-expressed, and endocytosed PRL also co-localized with rab4 and rab5A, markers for the early endosome, and with rab3D, a marker for regulated exocrine secretory vesicles. Endocytosed PRL was stored in intact form and released in response to stimulation with carbachol. Subcellular fractionation analysis detected relative excesses of PRL over PRLR in fractions that contained fragments of the recycling endosome and fractions that contained both secretory vesicle fragments and prelysosomal and autolysosomal fragments. EM-gold microscopy demonstrated PRL within small vesicles, consistent with endosomes or secondary lysosomes, and in large vesicles, consistent with regulated secretory vesicles. The secretory vesicles were preponderantly localized in the apical cytoplasm of control cells, and in the basal cytoplasm of PRL over-expressing cells. These results indicate that when lacrimal epithelial cells synthesize PRL, and when they endocytose it from their ambient medium, they traffic it both into the endosomes that constitute the constitutive transcytotic paracrine apparatus and also into regulated secretory vesicles, which are associated with the exocrine apparatus at low PRL levels and with the induced paracrine apparatus at high PRL levels.

Ultrastructural dynamics of the human endometrium from 14 to 22 weeks of gestation

In order to elucidate the ultrastructural dynamics of endometrium differentiation, uterine samples of fetuses aged 14 to 22 weeks of gestation (WG) were analyzed. Samples were processed for light (LM), transmission (TEM) and field-emission scanning electron microscopy (FE-SEM). Initial stratification of the uterine wall occurred at 14 WG: endometrial, myometrial, and perimetrial primordia were identified. At this age, the endometrial epithelium was simple columnar to pseudostratified and consisted of microvillous cells. Blood capillaries developed mainly in the stroma and between the myometrium and perimetrium primordia. At 18-20 WG the endometrial epithelium became clearly pseudostratified, with active ciliogenesis and a predominance of microvillous cells. Primordia of tubular glands were present at 20 WG. Microvillous cells still predominated in the endometrial epithelium at 21-22 WG and showed morphological features of apoptosis. The endometrial stroma at this stage was organizing into a thick lamina propria provided with subepithelial capillary plexuses. However, the stroma was formed by still undifferentiated mesenchymal cells during the whole period of study. Our data showed that the epithelial differentiation and distribution in the uterus occur in the human fetus in a similar way as in the adult. The above events are likely the expression of an early developmental patterning and related to future reproductive processes, such as the regulation of gamete passage and blastocyst implantation. Because the structure of the adult uterus is determined by the degree of paramesonephric duct fusion, septum absorption, and differentiation of the uterine primordial layers, our study may contribute toward clarifying to normal urogenital development.

Ion concentrations in oviduct and uterine fluid and blood serum during the estrous cycle in the bovine

In the bovine up to 40% of embryos die before implantation but despite the importance of ions in oviduct and uterine fluid formation and in gamete, zygote and early embryo development there is very little published information on the ion concentrations of oviduct or uterine fluid. The free anions chloride, phosphate and sulphate and the free cations sodium, calcium, magnesium and potassium were measured in oviduct fluid on days 0, 2, 4 and 6 and in uterine fluid on days 6, 8 and 14 and in corresponding blood samples. Oviduct and uterine fluids were collected in situ. Sodium was 25-fold higher than potassium and 80-fold higher than the other ions and chloride was 10-fold higher than potassium and 40-fold higher than the other ions in oviduct and uterine fluid. Phosphate, sulphate, magnesium, potassium and calcium were at lower concentrations in all fluids. Oviduct calcium and sodium were higher on day 0 than other days. The most striking uterine differences were the higher potassium and lower chloride, sodium and magnesium on day 14 than other days. There were significant positive associations between oviduct and blood chloride, sulphate, magnesium and calcium while only uterine sulphate was positively related to its blood concentration. There was no relationship between fluid secretion rate and no association between the concentrations of systemic progesterone or oestradiol and any ion in oviduct or uterine fluid. The different concentrations and associations between ions in the oviduct, uterus and blood suggest a differential regulation of ion secretion by the oviduct and uterine epithelia.

Comparative temporal and dose-dependent morphological and transcriptional uterine effects elicited by tamoxifen and ethynylestradiol in immature, ovariectomized mice

BACKGROUND

Uterine temporal and dose-dependent histopathologic, morphometric and gene expression responses to the selective estrogen receptor modulator tamoxifen (TAM) were comprehensively examined to further elucidate its estrogen receptor-mediated effects. These results were systematically compared to the effects elicited by the potent estrogen receptor ligand 17alpha-ethynylestradiol (EE) to identify pathways similarly and uniquely modified by each compound.

RESULTS

Three daily doses of 100 microg/kg TAM elicited a dose-dependent increase in uterine wet weight (UWW) in immature, ovariectomized C57BL/6 mice at 72 hrs with concurrent increases in luminal epithelial cell height (LECH), luminal circumference and glandular epithelial tubule number. Significant UWW and LECH increases were detected at 24 hrs after a single dose of 100 microg/kg TAM. cDNA microarray analysis identified 2235 differentially expressed genes following a single dose of 100 microg/kg TAM at 2, 4, 8, 12, 18 and 24 hrs, and at 72 hrs after three daily doses (3 x 24 hrs). Functional annotation of differentially expressed genes was associated with cell growth and proliferation, cytoskeletal organization, extracellular matrix modification, nucleotide synthesis, DNA replication, protein synthesis and turnover, lipid metabolism, glycolysis and immunological responses as is expected from the uterotrophic response. Comparative analysis of TAM and EE treatments identified 1209 common, differentially expressed genes, the majority of which exhibited similar profiles despite a temporal delay in TAM elicited responses. However, several conserved and treatment specific responses were identified that are consistent with proliferation (Fos, Cdkn1a, Anapc1), and water imbibition (Slc30a3, Slc30a5) responses elicited by EE.

CONCLUSION

Overall, TAM and EE share similar gene expression profiles. However, TAM responses exhibit lower efficacy, while responses unique to EE are consistent with the physiological differences elicited between compounds.

Caracterização das áreas hemófagas da placenta bovina

A região específica da interface materno-fetal corresponde à zona arcada do placentônio ovino e caprino. Em pequenos ruminantes esta área é também caracterizada por sangue materno extravasado (áreas hemófagas). É possível que o ferro seja transferido para o feto por eritrofagocitose trofoblástica nestas áreas. Para investigar as áreas hemófagas na placenta bovina, foram analisados placentônios de 34 vacas zebuínas gestantes (dois a três, quatro a seis, sete a oito, e nove meses de prenhez). O material foi fixado com solução aquosa de formaldeído a 10% e paraformaldeído a 4%, em tampão fosfato, pH 7,4, 0,1M, sendo processado e corado para microscopia de luz e histoquímica. Os hematomas placentários foram observados entre o epitélio uterino e trofoblástico, a partir de três meses de prenhez. A presença de eritrócitos nas células trofoblásticas elucidou a eritrofago-citose. A reação histoquímica de Perl's permitiu provar a existência de ferro férrico no trofoblasto. A reação de PAS foi po-sitiva, marcando substância mucóide nas células epiteliais e, principalmente, nas células binucleadas do epitélio fetal. Baseando-se nas características histológicas e histoquímicas, inferimos que as áreas hemófagas são sítios importantes para a transferência de ferro na placenta bovina.

Cellular localization and function of the antiviral protein, ovine Mx1 (oMx1): I. Ovine Mx1 is secreted by endometrial epithelial cells via an 'unconventional' secretory pathway

PROBLEM

Embryonic loss is a major contributor to infertility. Understanding factors contributing to embryonic loss will aid in development of technologies to improve/regulate fertility in animals and humans.

METHOD OF STUDY

We tested the hypothesis that the antiviral protein, ovine Mx1 (oMx1), is secreted by uterine epithelial cells. Uterine flushes were obtained from cyclic and early pregnant ewes and examined for levels of oMx1 protein. The pathway for ovine Mx1 secretion in ovine glandular epithelial (oGE) cells was determined using brefeldin A (BFA), an inhibitor of the conventional secretory pathway. Effects of BFA were determined using beta2-microglobulin (beta2MG) as a marker for the conventional secretory pathway, and interferon stimulated gene 15 (ISG15) and Galectin-1 (Gal-1) as markers for the unconventional secretory pathways.

RESULTS

Ovine Mx1 protein levels were low in uterine flushes from cyclic ewes and levels increased in pregnant ewes after D 15. Ovine GE cells secreted oMx1 in response to interferon and secretion was not reduced by BFA, suggesting oMx1 was secreted via an unconventional secretory pathway. beta2MG secretion was reduced by BFA, whereas ISG15 and Gal-1 were not.

CONCLUSION

This is the first report that the antiviral protein, oMx1, is secreted and provides evidence that secretion occurs via unconventional secretory pathway(s).

Progesterone-induced sphingosine kinase-1 expression in the rat uterus during pregnancy and signaling consequences

Sphingosine 1-phosphate (Sph-1-P), a product of sphingomyelin metabolism, can act via a family of cognate G protein-coupled receptors or as an intracellular second messenger for agonists acting through their membrane receptors. In view of the general growth promoting and developmental effects of Sph-1-P on target cells, we hypothesized that it plays a role in adaptation of the uterus to pregnancy. We analyzed its potential role and that of the related lysophospholipid lysophosphatidic acid in the pregnant rat uterus by examining changes in mRNA levels of cognate receptors and enzymes involved in their turnover. Of these, only sphingosine kinase-1 (SphK1) was markedly changed ( approximately 30-fold increase), being localized in the glandular epithelium, vasculature, and the myometrium. Uterine SphK1 mRNA and protein levels paralleled those of serum progesterone, and treatment with progesterone or an antagonist elevated or reduced SphK1 mRNA expression, respectively. Progesterone also increased SphK1 mRNA steady-state levels in a rat myometrial/leiomyoma cell line (ELT3). Overexpressing human SphK1 in these cells resulted in increased levels of the cell cycle regulator cyclin D1 and increased myosin light-chain phosphorylation. Ectopic expression of SphK1 also resulted in increased proliferation rates, possibly in conjunction with increased cyclin D1 expression. These studies suggest that the uterine expression of SphK1 mediates processes involved in growth and differentiation of uterine tissues during pregnancy.

Human early placental development: potential roles of the endometrial glands

There is strong evidence that the endometrial glands play a key role in regulating placental development in many domestic species, but their contribution in the human has largely been ignored once implantation is complete. Here we re-evaluate their role during the first trimester. Connections between the glands and the intervillous space have been observed from day 17 post-conception through to the end of the first trimester. In the absence of a maternal arterial supply to the early placenta it is believed that the carbohydrate- and lipid-rich secretions represent an important source of nutrients during the first trimester, and possibly the beginning of the second trimester. The secretions also contain a variety of growth factors that may regulate placental morphogenesis since their receptors are present on villous and extravillous trophoblast, and villous endothelial cells. Other components of the secretions may modulate immune responses and trophoblast invasion at the materno-fetal interface. We speculate that lactogenic hormones secreted by decidual cells and the syncytiotrophoblast may act in concert with human chorionic gonadotropin to stimulate the secretory activity of glandular epithelial cells during the first trimester. There is circumstantial evidence, but as yet no conclusive proof, that deficient glandular activity is associated with pregnancy failure in the human.

Dietary isoflavones act on bone marrow osteoprogenitor cells and stimulate ovary development before influencing bone mass in pre-pubertal piglets

Food containing soybeans provide isoflavone phytoestrogens that can preserve bone mass in postmenopausal women, and prevent bone loss in ovariectomized rats. But their effects on bone remain unclear, particularly on bone formation during growth. Two groups of eight pre-pubertal piglets were fed a basal or an isoflavone-enriched (S800) diet for 6 weeks. The S800 diet contained 800 mg SoyLifetrade mark/kg, providing 2.8 mg isoflavones/kg body weight/day. Several bones were collected and tested for bone strength and density. Bone marrow was collected from humeri together with blood samples and genital tracts. The plasma concentrations of isoflavones were increased in the pigs fed S800, but growth rate, body weight, plasma bone markers, bone mineral density, and strength were all unaffected. In contrast, cultured stromal cells from S800 pigs had more alkaline phosphatase-rich cells and mineralized nodules, secreted more osteocalcin, osteoprotegerin and RANK-L, synthesized more osteoprotegerin, and RANK-L. Cultured mononucleated nonadherent bone marrow cells from S800 pigs developed fewer tartrate-resistant acid phosphatase mononucleated cells (osteoclast progenitors) when cultured with 1,25(OH)(2)D(3), and resorbed a smaller area of dentine slices. Freshly isolated bone marrow osteoclast progenitors from S800 pigs had more caspase-3 cleavage activity, and synthesized less RANK. Both osteoclast and osteoblast progenitors had ERalpha and ERbeta, whose syntheses were stimulated by the S800 diet. The S800 piglets had heavier ovaries with more follicles, but their uterus weight was unaffected. We conclude that dietary isoflavones have no detectable effect on the bone mass of growing female piglets, but act on bone marrow osteoprogenitors via ERs--mainly ERbeta, and stimulate ovary development.

Effects of dam nutrition on growth and reproductive performance of heifer calves1

A 3-yr study was conducted with heifers (n = 170) whose dams were used in a 2 x 2 factorial arrangement of treatments to determine the effects of late gestation (LG) or early lactation (EL) dam nutrition on subsequent heifer growth and reproduction. In LG, cows received 0.45 kg/d of a 42% CP supplement (PS) or no supplement (NS) while grazing dormant Sandhills range. During EL, cows from each late gestational treatment were fed cool-season grass hay or grazed sub-irrigated meadow. Cows were managed as a single herd for the remainder of the year. Birth date and birth weight of heifer calves were not affected (P > 0.10) by dam nutrition. Meadow grazing and PS increased (P = 0.02; P = 0.07) heifer 205-d BW vs. feeding hay and NS, respectively. Weight at prebreeding and pregnancy diagnosis were greater (P < 0.04) for heifers from PS dams but were unaffected by EL nutrition (P > 0.10). There was no effect (P > 0.10) of LG or EL dam nutrition on age at puberty or the percentage of heifers cycling before breeding. There was no difference (P > 0.10) in pregnancy rates due to EL treatment. Pregnancy rates were greater (P = 0.05) for heifers from PS dams, and a greater proportion (P = 0.005) of heifers from PS dams calved in the first 21 d of the heifers' first calving season. Nutrition of the dams did not influence (P < 0.10) heifers' average calving date, calving difficulty, and calf birth weight during the initial calving season. Weight at the beginning of the second breeding season was greater (P = 0.005) for heifers from PS dams but was not affected by maternal nutrition during EL (P > 0.10). Dam nutrition did not affect (P > 0.10) heifer ADG or G:F ratio. Heifers from PS dams had greater DMI (P = 0.09) and residual feed intake (P = 0.07) than heifers from NS cows if their dams were fed hay during EL but not if their dams grazed meadows. Heifers born to PS cows were heavier at weaning, prebreeding, first pregnancy diagnosis, and before their second breeding season. Heifers from cows that grazed meadows during EL were heavier at weaning but not postweaning. Despite similar ages at puberty and similar proportions of heifers cycling before the breeding season, a greater proportion of heifers from PS dams calved in the first 21 d of the heifers' first calving season, and pregnancy rates were greater compared with heifers from NS dams. Collectively, these results provide evidence of a fetal programming effect on heifer postweaning BW and fertility.

Minimal uterine serous carcinoma: current concepts in diagnosis and prognosis

Uterine serous carcinoma (USC) is an aggressive type of endometrial cancer with a propensity to have extra-uterine spread at diagnosis, in some cases despite limited involvement of the uterus. Serous endometrial intra-epithelial carcinoma (EIC) is a recently recognised entity with the same cytological features and p53 mutations as USC, but it does not demonstrate stromal or myometrial invasion. In addition to representing the putative precursor to USC, the pure form of serous EIC may also be associated with extra-uterine tumour at the time of diagnosis and with risk for recurrence, spread, and eventual death from tumour. Current evidence indicates that serous EIC is a form of minimal USC with behaviour that is stage dependent, thereby necessitating complete surgical staging despite limited disease in the uterus. We review the diagnostic criteria for minimal USC, pitfalls in the differential diagnosis, and discuss a practical approach to evaluating biopsies, polypectomies, or hysterectomies containing minimal USC.

Regulation of HOXA10 expression by phytoestrogens

HOXA10 is necessary for normal development of the Müllerian duct, and continued adult expression in the uterus is necessary for female fertility. HOXA10 expression is altered by diethylstilbestrol, leading to uterine anomalies. Other endocrine disruptors may potentially lead to reproductive anomalies or dysfunction by altering HOXA10 expression. Here we investigated the effect of isoflavones on HOXA10 expression after in utero or adult exposure in the mouse. Genistein, but not diadzein, regulated HOXA10 mRNA and protein expression in the adult mouse uterus. In contrast, in utero genistein or diadzein exposure had no lasting effect on HOXA10 expression in the exposed offspring. Reporter gene expression driven by the HOXA10 estrogen response element was increased in a dose-responsive manner by genistein, but not daidzein. Neither estrogen receptor-alpha nor estrogen receptor-beta binding to the HOXA10 estrogen response element was affected by genistein or daidzein. In utero exposure to isoflavones is unlikely to result in HOXA10-mediated developmental anomalies. Adult genistein exposure alters uterine HOXA10 expression, a potential mechanism by which this agent affects fertility.

Expression of Smad ubiquitin regulatory factor 2 (Smurf2) in rhesus monkey endometrium and placenta during early pregnancy

Smad ubiquitin regulatory factor 2 (Smurf2) is an E3 ubiquitin ligase that is involved in the Smad-mediated TGF-beta signaling. TGF-beta has been shown to play an important role during normal embryo implantation, but whether Smurf2 is involved in this process has not been reported. This study was first conducted to investigate the expression of Smurf2 transcript and protein in different compartments of the rhesus monkey uteri and placenta during early pregnancy. The results showed that both the cloned partial sequence of Smurf2 gene and the corresponding amino acid residues shared 99% identity with those of human homologs. On day 12 (D12) of pregnancy, strong signals of Smurf2 mRNA were found in basalis glandular epithelium and luminal epithelium, and moderate expressions were detected in functionalis glandular epithelium. During early villi stage and villi placental stage, Smurf2 mRNAs were mainly localized in the placenta villi, trophoblastic column, trophoblastic shell, and basalis glandular epithelium. There appeared strong staining signals in the arterioles on D26 of pregnancy, but faint staining signals on D18 of pregnancy. No specific staining of Smurf2 mRNA was observed in stromal cells and myometrium. The expression pattern of Smurf2 protein was generally similar to that of its mRNA. These results provide the first evidence that Smurf2 may play specific roles in glandular secretion, trophoblastic cell invasion, and placentation through mediating the expression of the related proteins of TGF-beta signaling pathway during early pregnancy.

A one-year neonatal mouse carcinogenesis study of quinacrine dihydrochloride

Quinacrine is an acridine derivative under investigation for its use in nonsurgical female sterilization. Safety issues regarding the carcinogenic potential of quinacrine have been raised because it is mutagenic and clastogenic in vitro. The objective of the study was to evaluate the carcinogenic potential of quinacrine dihydrochloride (quinacrine) in neonatal mice treated with single intraperitoneal doses on postpartum days 8 and 15 and observed for 52 weeks. Neonatal Crl: CD-1 mice of each sex were randomly allocated into four treatment groups (0, 10, 50, and 150 mg/kg), dosed twice with quinacrine suspended in carboxymethylcellulose, observed for 52 weeks post dose, and then euthanized, necropsied, and subjected to a full histopathological examination. In male mice, tumor incidence was not significantly increased at any site at any dose level. In female mice, the incidence of benign uterine endometrial stromal polyps was slightly greater at the mid and high dose (> or = 50 mg/kg), as was the incidence of endometrial hyperplasia. The incidence of polyps in these groups was not significantly greater than in controls by pair-wise comparison but was significantly greater (p = .042) by the linear trend test. The authors conclude that quinacrine administered twice to neonatal mice may have enhanced or accelerated the development of endometrial hyperplasia and uterine stromal polyps at higher doses. Because uterine stromal polyps are a commonly observed benign tumor in older mice, the significance of this finding is unclear and will require a weight of evidence evaluation for a conclusion on the carcinogenic potential of quinacrine.

Mining the mouse transcriptome of receptive endometrium reveals distinct molecular signatures for the luminal and glandular epithelium

Epithelia coat most tissues where they sense and respond to the environment and participate in innate immune responses. In the adult mouse uterus, columnar epithelium lines the central lumen and the glands that penetrate the underlying stroma. A nidatory surge of estrogen causes differentiation of the luminal epithelium to the receptive state that permits blastocyst attachment and allows subsequent implantation. Here, using laser-capture microdissection to isolate the luminal and glandular epithelia separately, we have profiled gene expression 2 h before embryo attachment to determine whether there are unique roles for these two epithelial structures in this process. Although most genes were expressed in both compartments, there was greater expression of 153 and 118 genes in the lumen and glands, respectively. In the luminal epithelium, there is enrichment in lipid, metal-ion binding, and carbohydrate-metabolizing enzymes, whereas in the glands, immune response genes are emphasized. In situ hybridization to uterine sections obtained from mice during the preimplantation period validated these data and indicated an array of previously undocumented genes expressed with unique patterns in these epithelia. The data show that each epithelial compartment has a distinct molecular signature and that they act differentially and synergistically to permit blastocyst implantation.

Trophoblast cells of ruminant placentas—A minireview

The ruminant placenta is classified as cotyledonary and synepitheliochorial on the basis of its gross anatomical features and histological characteristics, respectively. The richly vascularized embryonic chorioallantois is lined on its external surface by cells of the trophectodermal epithelium. These cells which assume specialized functions are referred to as trophoblast cells. Two morphologically and functionally distinct cell types have been recognized in the trophectoderm of the placenta of ruminant animals. These are the mononucleate trophoblast cells and the binucleate trophoblast cells. The occurrence, morphological characteristics, and specialized functions of these trophoblast cells, in relation to conceptus nutrition and survival in utero are discussed in this review.

Expression of prostasin and protease nexin-1 in rhesus monkey (Macaca mulatta) endometrium and placenta during early pregnancy

Serine proteases have been documented to play key roles in uterine matrix turnover and trophoblastic invasion during implantation. Roles of prostasin serine protease in these processes, however, are currently unclear. The present study was first conducted to investigate the colocalization of prostasin and its cognate serpin, protease nexin-1 (PN-1), in rhesus monkey endometrium and placenta on days 12, 18, and 26 of pregnancy by using in situ hybridization (ISH) and immunohistochemistry. With ISH, expression of prostasin mRNA was intensely localized in the glandular epithelium on days 12 and 18 and in the placental villi, trophoblastic column, trophoblastic shell, and fetal-maternal border on days 18 and 26. With the progress of pregnancy, expression level in the glandular epithelium was significantly decreased, and the accumulation in the placental compartments was further increased. In addition, the stroma and arterioles exhibited modest levels of prostasin signals. However, expression level of PN-1 in these compartments on adjacent sections in the three stages of early pregnancy was weak or below the level of detection. Prostasin protein expression in the endometrium was found to be consistent with the distribution patterns revealed in the ISH experiments. It may be suggested from these results that prostasin is involved in endometrial epithelial morphology establishment, tissue remodeling, and trophoblastic invasion during early pregnancy. The cognate serpin PN-1 was not coordinately expressed along with prostasin, creating a tissue environment favorable for proteolytic activities of prostasin during early pregnancy events.

Demonstration of ubiquitin thiolester formation of UBE2Q2 (UBCi), a novel ubiquitin-conjugating enzyme with implantation site-specific expression

We recently identified a differentially expressed gene in implantation stage rabbit endometrium encoding a new member of the ubiquitin-conjugating enzyme family designated UBE2Q2 (also known as UBCi). Its unusually high molecular mass, novel N-terminus extension, and highly selective pattern of mRNA expression suggest a specific function in implantation. This study analyzes its relationship to the E2 ubiquitin-conjugating enzyme superfamily, investigates its enzymatic activity, and examines its localization in implantation site endometrium. Construction of a dendrogram indicated that UBE2Q2 is homologous to the UBC2 family of enzymes, and isoforms are present in a broad range of species. In vitro enzymatic assays of ubiquitin thiolester formation demonstrated that UBE2Q2 is a functional ubiquitin-conjugating enzyme. The Km for transfer of ubiquitin thiolester from E1 to UBE2Q2 is 817 nM compared to 100 nM for other E2 paralogs; this suggests that the unique amino terminal domain of UBE2Q2 confers specific functional differences. Affinity-purified antibodies prepared with purified recombinant UBE2Q2 showed that the protein was undetectable by immunoblot analysis in endometrial lysates from estrous and Day 6(3/4) pregnant (blastocyst attachment stage) rabbits but was expressed in both mesometrial and antimesometrial implantation site endometrium of Day 8 pregnant animals. No expression was detected in adjacent interimplantion sites. Immunohistochemistry demonstrated UBE2Q2 expression exclusively in mesometrial and antimesometrial endometrial luminal epithelial cells of the Day 8 implantation chamber. Immunohistochemical localization of ubiquitin mirrored UBE2Q2 expression, with low-to-undetectable levels in implantation sites of Day 6(3/4) pregnant endometrium but high levels in luminal epithelial cells of Day 8 pregnant endometrium. This implantation site-specific expression of UBE2Q2 in luminal epithelial cells could play major roles in orchestrating differentiation events through the modification of specific protein substrates.

Macroscopic and microscopic aspects of collared peccary and white-lipped peccary placenta

This study examines middle and late gestational placentae from 13 Tayassu tajacu (collared peccary) and 3 Tayassu pecari (white-lipped peccary), which are Artiodactyla belonging to the Family Tayassuidae. The chorionic sac of Tayassu species is diffuse and chorioallantoic. These epitheliochorial placentae show no trophoblast invasion into the uterine epithelium and there is interdigitation between fetal and maternal microvilli. Two distinct regions of the fetomaternal interface can be identified: the interareolar and the areolar regions. The uterine epithelium has eosinophilic cytoplasm with dispersed, basophilic and electron-dense granules. Trophoblast cells are irregularly cuboidal on top of the fetal ridges and columnar on troughs, where cells have cytoplasmic vesicles and large basal vacuoles, surrounded by whorls of smooth membranes. Capillaries indent the trophoblast cells forming a placental barrier 3 microm or less thick. The columnar uterine glandular epithelium has a subpopulation of granules staining with Perl's Prussian blue reaction, suggesting iron secretion. In areolar areas, the trophoblast cells show apical microvilli, a basophilic cytoplasm with electron-dense intracellular vacuoles and cisternae. The placenta can therefore be classified as non-deciduate. The ultrastructural aspects of this study reveal features that have not previously been described and extend our knowledge of functions relating to materno-fetal transport in these species.

Aquaporin-2 expression in human endometrium correlates with serum ovarian steroid hormones

The aim of the present study was to examine the expression of aquaporin-2 (AQP2), a member of the water channel family aquaporins (AQPs), in human uterine endometrium and its modulation of ovarian steroid hormone at the proliferative and secretory phases. Western blot, immunohistochemistry, and RT-PCR were employed in the present study. Western blot revealed a 29-kDa band that represented AQP2 in human endometrium. The expression of AQP2 in endometrium was confirmed by RT-PCR and immunohistochemical results. The immunohistochemical analysis demonstrated that AQP2 was prominent in luminal and glandular epithelial cells of endometrium. The levels of endometrial AQP2 expression changed during the menstrual cycle and were higher in the secretory endometrium than in the proliferative endometrium. A significantly high level of AQP2 was detected at the mid-secretory phase. There was a positive correlation between the levels of the endometrial AQP2 expression and the concentrations of the serum 17beta-estradiol (E2) or/and progesterone (P4). These data for the first time corroborate that AQP2 is expressed in human endometrium and that the expression of AQP2 in human endometrium might be regulated by E2 or/and P4. The changed expression of AQP2 at different phases of the menstrual cycle may be essential to reproductive physiology in human. The high level of endometrial AQP2 expression was observed at the mid-secretory phase, the time of embryo implantation, suggesting that AQP2 might play physiological roles in the uterine receptivity.

WNT pathways in the neonatal ovine uterus: potential specification of endometrial gland morphogenesis by SFRP2

Endometrial glands are critical for uterine function and develop between birth (Postnatal Day [P] 0) and P56 in the neonatal ewe. Endometrial gland morphogenesis or adenogenesis involves the site-specific budding differentiation of the glandular epithelium from the luminal epithelium followed by their coiling/branching development within the stroma of the intercaruncular areas of the endometrium. To determine whether WNT signaling regulates endometrial adenogenesis, the WNT signaling system was studied in the neonatal ovine uterus. WNT5A, WNT7A, and WNT11 were expressed in the uterine epithelia, whereas WNT2B was in the stroma. The WNT receptors FZD2 and FZD6 and coreceptor LRP6 were detected in all uterine cells, and FZD6 was particularly abundant in the endometrial epithelia. Secreted FZD-related protein-2 (SFRP2), a WNT antagonist, was not detected in the P0 uterus, but was abundant in the aglandular caruncular areas of the endometrium between P7 and P56. Exposure of ewes to estrogens during critical developmental periods inhibits or retards endometrial adenogenesis. Estrogen-induced disruption of endometrial adenogenesis was associated with reduction or ablation of WNT2B, WNT7A, and WNT11, and with an increase in WNT2 and SFRP2 mRNA, depending on exposure period. Collectively, results implicate the canonical and noncanonical WNT pathways in regulation of postnatal ovine uterine development and endometrial adenogenesis. Expression of SFRP2 in aglandular caruncular areas may inhibit the WNT signaling pathway, thereby concentrating WNT signaling and restricting endometrial adenogenesis in the intercaruncular areas of the uterus. Further, estrogen-induced inhibition of adenogenesis may be mediated by a reduction in WNT signaling caused by aberrant induction of SFRP2 and loss of several critical WNTs.

Pregnancy effects on distribution of progesterone receptors, oestrogen receptor α, glucocorticoid receptors, Ki-67 antigen and apoptosis in the bovine interplacentomal uterine wall and foetal membranes

Until recently, studies dealing with the uterus of the pregnant cow focus primarily on the placentome or on early and late pregnancy. Thus, there is a paucity of information about many aspects of the interplacentomal uterine wall including adherent foetal membranes. Corresponding tissue specimens were collected at the slaughterhouse and in animals undergoing premature caesarean section. Two specimens per month of pregnancy were assessed immunohistochemically for progesterone receptors, oestrogen receptor alpha and glucocorticoid receptors, Ki-67 protein and TUNEL procedure was performed. The latter two methods were employed in three animals each per months 1 and 2, 3 and 4, 7 and 8 and in six animals undergoing caesarean section at days 274 and 275 post insemination or during spontaneous labour. Results indicate that proliferation and apoptosis are of minor importance for tissue homeostasis since both can histochemically be detected only sporadically. Thus, at the sites investigated here, cellular hypertrophy plays an important role for tissue growth during pregnancy. Progesterone receptors, oestrogen receptor alpha and glucocorticoid receptors, however, exhibit cell type and pregnancy stage specific distribution patterns within the tissues assessed. Progesterone receptor immunoreactive scores remained fairly unchanged during pregnancy. Oestrogen receptor alpha scores, however, generally decreased and glucocorticoid receptors increased with ongoing gestation. Progesterone receptors and oestrogen receptor alpha were present in endometrial stroma and in myometrial smooth muscle cells during whole pregnancy. Oestrogen receptor alpha was detectable during whole pregnancy also in uterine glands. Progesterone receptors were, however, present at a very low level at the latter site only during months 1-3 and 6-9. Oestrogen receptor alpha and glucocorticoid receptors may also mediate uterine blood flow since they were present in the tunica media of uterine blood vessels. Results of the present study indicate, that progesterone and its receptor play an important role during whole gestation, mainly for uterine quiescence. Glucocorticoids and their receptors - possibly in cooperation with oestrogens and decreasing amounts of the oestrogen receptor alpha - should trigger processes initiating parturition, such as endometrial prostaglandin production. Further studies - including the periparturient period - should help to understand the exact role of the extraplacental compartment of the uterine wall for the initiation and progress of parturition.

Development of the mammalian female reproductive tract

The female reproductive tract (FRT), which includes the oviduct, uterus, cervix and vagina, is critical for mammalian reproduction. Recent research using knockout mice has contributed substantially to our understanding of the molecular mechanisms governing FRT development. Aside from satisfying our curiosities about the origin of life, these studies have provided us with a better understanding of FRT disorders and ways to improve female fertility. Here we review genes that are involved in various stages of sexual duct formation and development in mammals. In addition, the effect of exogenous estrogen such as DES on FRT development is also discussed.

Carbonic Anhydrase Regulate Endometrial Gland Development in the Neonatal Uterus1

Carbonic anhydrases (CAs) are zinc metalloenyzmes that catalyze the reversible conversion of carbon dioxide to carbonic acid and are involved in respiration, calcification, acid-base balance, and formation of fluids. Transcriptional profiling of the developing neonatal mouse uterus detected expression of Car1, Car2, Car11, and Car13 between Postnatal Days (PNDs) 3 and 18. In the neonatal mouse uterus, Car2 and Car11 mRNAs were predominantly localized in endometrial epithelial and stromal cells, respectively, whereas Car13 mRNA was detected in both epithelia and stroma. CAR2 protein was detected primarily in the endometrial epithelia and from PND 3 to PND 18 in the uteri of neonatal mice. To determine whether CA regulated uterine development, neonatal mice were treated s.c. with acetazolamide, a CA inhibitor, from PND 3 to PND 18. Treatment with acetazolamide decreased CA activity in the uterus and the number of endometrial glands without apparent effects on differentiation of the stroma or myometrium. In the neonatal sheep uterus, CA2 mRNA was initially expressed at birth (PND 0) in the endometrial luminal epithelium and was predominantly expressed in the developing glandular epithelium from PND 7 to PND 56. These results support the hypothesis that CA has a functional role in endometrial gland development during postnatal uterine morphogenesis.

Estrogen disruption of neonatal ovine uterine development: effects on gene expression assessed by suppression subtraction hybridization

Inappropriate exposure of neonatal sheep to estrogen during critical developmental periods inhibits or retards endometrial gland morphogenesis and reduces uterine growth. Studies were conducted to identify mechanisms mediating estrogen disruption of neonatal ovine uterine development by analysis of candidate growth factor systems and using suppression subtraction hybridization (SSH). In study 1, sheep were exposed either to corn oil as a control or to estradiol valerate (EV) from birth to Postnatal Day (PND) 14, which ablated endometrial gland development. Estradiol valerate decreased uterine FGF7 (fibroblast growth factor 7) and MET (hepatocyte growth factor receptor) expression and increased INHBA (inhibin betaA). The SSH identified a number of genes responsive to EV, which included GSTM3 (glutathione S-transferase), IDH1 (cytosolic NADP-isocitrate dehydrogenase), PECI (peroxisomal D(3),D(2)-enoyl-coenzyme A isomerase), OAS1 (2',5'-oligoadenylate 40/46-kDa synthetase), IGFBP3 (insulin-like growth factor-binding protein-3), TEGT (testis-enhanced gene transcript), CXCL10 (interferon-gamma-inducible protein 10), and IGLV (immunoglobulin V). These mRNAs were expressed predominantly in the endometrial epithelia (GSTM3, IDH1, PEC1, OAS1, and TEGT), stroma (IGFBP3), or immune cells (CXCL10 and IGLV). In study 2, effects of estrogen exposure on uterine gene expression were determined during three different critical developmental periods (PNDs 0-14, 14- 28, and 42-56). Estrogen exposure decreased expression of the SSH-identified genes, particularly those from PNDs 0-14. These studies suggest that estrogen disruption of postnatal uterine development involves period-specific effects on expression of genes predominantly in the endometrial epithelium. The SSH-identified, estrogen-disrupted genes represent new candidate regulators of postnatal endometrial adenogenesis.

The IGF system in the neonatal ovine uterus

Postnatal development of the ovine uterus primarily involves uterine gland morphogenesis or adenogenesis. Adenogenesis involves the budding differentiation of the glandular epithelium (GE) from the luminal epithelium (LE) and then GE proliferation and coiling/branching morphogenetic development within the stroma between birth (postnatal day or PND 0) and PND 56. Insulin-like growth factor (IGF)-I and IGF-II mRNAs were previously found to be expressed only in the endometrial stroma, whereas the IGF receptor (IGF-1R) mRNA was most abundant in epithelia and in stroma, suggesting that an intrinsic IGF system regulates postnatal development of the uterus. Given that the biological activities of IGFs are modulated by a family of six IGF binding proteins (IGFBPs) and specific proteases, the objective was to determine the effects of age and estrogen disruption on expression of IGFs, IGFBPs and pregnancy-associated plasma protein A (PAPP-A or IGFBP-4 protease) in the ovine uterus. In Study One, circulating levels of IGF-I and IGF-II in the serum of neonatal ewes did not change between PND 0 and PND 56. Levels of immunoreactive IGF-I, IGF-II and IGF-1R protein were most abundant on the apical surface of the endometrial LE and GE. RT-PCR analyses detected expression of IGFBPs (3, 4, 5 and 6) as well as PAPP-A mRNAs in the uterus, but not IGFBP-1 and IGFBP-2 mRNAs. IGFBP-3 and IGFBP-4 mRNAs were expressed specifically in the endometrial stroma and myometrium and increased after birth. PAPP-A mRNA was expressed specifically in the endometrial stroma and increased after birth. In Study Two, ewes were treated from birth with estradiol-17beta valerate (EV), which reduces uterine growth and inhibits endometrial adenogenesis. On PNDs 14 and 56, IGFBP-3 mRNA was decreased in the uterus of EV-treated ewes, but IGF-1R and IGFBP-4 mRNAs were not affected. PAPP-A mRNA was increased by EV treatment on PND 14, but decreased on PND 56. These results support the hypothesis that an intrinsic IGF system in the uterus regulates epithelial-stromal interactions important for postnatal uterine growth and endometrial gland morphogenesis in the sheep.

Expression of adamalysin 19/ADAM19 in the endometrium and placenta of rhesus monkey (Macaca mulatta) during early pregnancy

A disintegrin and metalloproteinase (ADAM) 19 may contribute to multiple processes including proteolysis, adhesion and intracellular signalling. These processes are also critical for embryo implantation. The aim of this study was to investigate the spatio-temporal expression of the ADAM19 in rhesus monkey uteri on days 12, 18 and 26 of pregnancy. The results showed that in the cloned monkey 346 bp ADAM19 gene fragment and 114 amino acid residues were 98 and 100% identical to those of human homologues, respectively. In-situ hybridization confirmed that the ADAM19 mRNA was located in the luminal and glandular epithelium on day 12 of pregnancy. On day 18 of pregnancy, strong signals of the ADAM19 mRNA were detected in the placental villi, trophoblastic column and glandular epithelium near the myometrium. Moderate expression of the ADAM19 mRNA was seen in the trophoblastic shell and stromal cells. The placental villi and trophoblastic column expressed abundant ADAM19 mRNA, and ADAM19 transcripts were also detected in the trophoblastic shell and fetal-maternal border on day 26 of pregnancy. The expression pattern of the ADAM19 protein was similar to its transcript, but signals for the ADAM19 protein in the stromal cells and trophoblastic shell increased more than its mRNA on day 18 of pregnancy. Statistical analysis demonstrated that the expression level of ADAM19 significantly increased on day 18 of pregnancy. These data suggest that the ADAM19 may be involved in the key processes of glandular secretion, trophoblast invasion and degradation of extracellular matrix during early pregnancy.

Actions of progesterone on uterine immunosuppression and endometrial gland development in the uterine gland knockout (UGKO) ewe

In ewes, the uterine gland knockout (UGKO) phenotype is caused by neonatal exposure to norgestomet to arrest uterine gland development and produce an adult which has a uterus characterized by the lack of endometrial glands. Since endometrial glands in the sheep produce the lymphocyte-inhibitory protein, ovine uterine serpin (OvUS), an experiment was conducted with ewes of the UGKO phenotype to evaluate whether the inhibitory actions of progesterone on tissue rejection responses in utero are dependent upon the presence of endometrial glands. Control and UGKO ewes were ovariectomized and subsequently treated with either 100 mg/day progesterone or corn oil vehicle for 30 days. An autograft and allograft of skin were then placed in each uterine lumen and treatments were continued for an additional 30 days before grafts were examined for survival. All autografts survived and had a healthy appearance after histological analysis. Allografts were generally rejected in ewes treated with vehicle but were present for hormone-treated ewes, regardless of uterine phenotype. Analysis of the histoarchitecture and protein synthetic capacity of the uterus revealed that progesterone induced differentiation of endometrial glands and synthesis and secretion of OvUS in UGKO ewes. The UGKO ewes had reduced density of CD45R+ lymphocytes in the endometrial epithelium and there was a tendency for progesterone to reduce this effect in luminal epithelium. Taken together, results confirm the actions of progesterone to inhibit graft rejection response in utero. Responses of UGKO ewes to progesterone indicate that the hormone can induce de novo development and differentiation of endometrial glands, at least when skin grafts are in the uterus.

Animal models of implantation

Implantation is an intricately timed event necessary in the process of viviparous birth that allows mammals to nourish and protect their young during early development. Human implantation begins when the blastocyst both assumes a fixed position in the uterus and establishes a more intimate relationship with the endometrium. Due to the impracticalities of studying implantation in humans, animal models are necessary to decipher the molecular and mechanical events of this process. This review will discuss the differences in implantation between different animal models and describe how these differences can be utilized to investigate discrete implantation stages. In addition, factors that have been shown to be involved in implantation in the human and other various animal models including growth factors, cytokines, modulators of cell adhesion, and developmental factors will be discussed, and examples from each will be given.

Comparative developmental biology of the mammalian uterus

The uterus is an essential organ for reproduction in mammals. Despite the importance of the uterus for the fertility and health of women and their offspring, relatively little is known about the hormonal, cellular, and molecular mechanisms that regulate development of the uterus in either the fetus or neonate. Disruption of uterine development in the fetus and neonate by genetic defects or exposure to endocrine disruptors can program the function of the uterus in the adult and lead to infertility, cancer, and even death. The intent of this chapter is to review the current knowledge of regulatory factors and pathways governing prenatal organogenesis and postnatal morphogenesis of the uterus in mammals, with a particular focus on laboratory and domestic animals. Prenatal organogenesis, postnatal morphogenesis, and adult functional differentiation of the uterus are complex, multifactorial processes. Although conservation of some factors and pathways are observed between species, it is clear that mutation of candidate genes in the mouse does not always recapitulate the same defects observed in the human. Therefore, comparative biology of the mechanisms regulating uterine development in other species may be useful to identify candidate genes and pathways to understand congenital abnormalities in humans. This knowledge is necessary to develop rational therapies to prevent and treat infertility and to enhance fertility in humans and domestic animals.

Implantation mechanisms: insights from the sheep

Implantation in all mammals involves shedding of the zona pellucida, followed by orientation, apposition, attachment and adhesion of the blastocyst to the endometrium. Endometrial invasion does not occur in domestic ruminants; thus, definitive implantation is achieved by adhesion of the mononuclear trophoblast cells to the endometrial lumenal epithelium (LE) and formation of syncytia by the fusion of trophoblast binucleate cells with the LE. This review highlights new information on mechanisms regulating the implantation cascade in sheep. The embryo enters the uterus on day 4 at the morula stage of development and then develops into a blastocyst by day 6. The blastocyst sheds the zona pellucida (day 8), elongates to a filamentous form (days 11–16), and adheres to the endometrial LE (day 16). Between days 14 and 16, the binucleate cells begin to differentiate in the trophoblast and subsequently migrate and fuse with the endometrial LE to form syncytia. Continuous exposure of the endometrium to progesterone in early pregnancy downregulates the progesterone receptors in the epithelia, a process which is associated with loss of the cell-surface mucin MUC1 and induction of several secreted adhesion proteins. Recurrent early pregnancy loss in the uterine gland knockout ewe model indicates that secretions of the endometrial epithelia have a physiologic role in blastocyst elongation and implantation. A number of endometrial proteins have been identified as potential regulators of blastocyst development and implantation in sheep, including glycosylated cell adhesion molecule 1 (GlyCAM-1), galectin-15, integrins and osteopontin. The epithelial derived secreted adhesion proteins (GlyCAM-1, galectin-15 and osteopontin) are expressed in a dynamic temporal and spatial manner and regulated by progesterone and/or interferon tau, which is the pregnancy recognition signal produced by the trophoblast during blastocyst elongation. The noninvasive and protracted nature of implantation in domestic animals provides valuable opportunities to investigate fundamental processes of implantation that are shared among all mammals. Understanding of the cellular and molecular signals that regulate uterine receptivity and implantation can be used to diagnose and identify causes of recurrent pregnancy loss and to improve pregnancy outcome in domestic animals and humans.

Developmental effects of prenatal exposure to bisphenol a on the uterus of rat offspring

Exposure to estrogenic compounds during critical periods of fetal development could result in adverse effects on the development of reproductive organs that are not apparent until later in life. Bisphenol A (BPA), which is employed in the manufacture of a wide range of consumer products, is a prime candidate for endocrine disruption. We examined BPA to address the question of whether in utero exposure affects the uterus of the offspring and studied the expression and distribution of the estrogen receptors alpha (ERalpha) and beta (ERbeta), because estrogens influence the development, growth, and function of the uterus through both receptors. Gravid Sprague-Dawley dams were administered by gavage either 0.1 or 50 mg/kg per day BPA or 0.2 mg/kg per day 17alpha-ethinyl estradiol (EE2) as reference dose on gestation days 6 through 21. Female offspring were killed in estrus. Uterine morphologic changes as well as ERalpha and ERbeta distribution and expression were measured by immunohistochemistry and Western blot analysis. Striking morphologic changes were observed in the uterine epithelium of postpubertal offspring during estrus of the in utero BPA-treated animals (the thickness of the total epithelium was significantly reduced). ERalpha expression was increased in the 50-mg BPA and EE2-treated group. In contrast, we observed significantly decreased ERbeta expression in all BPA- and EE2-treated animals when compared with the control. In summary, these results clearly indicate that in utero exposure of rats to BPA promotes uterine disruption in offspring. We hypothesize that the uterine disruption could possibly be provoked by a dysregulation of ERalpha and ERbeta.

Establishment and maintenance of human embryonic stem cell lines on human feeder cells derived from uterine endometrium under serum-free condition

Human embryonic stem (hES) cells are usually established and maintained on mouse embryonic fibroblast (MEFs) feeder layers. However, it is desirable to develop human feeder cells because animal feeder cells are associated with risks such as viral infection and/or pathogen transmission. In this study, we attempted to establish new hES cell lines using human uterine endometrial cells (hUECs) to prevent the risks associated with animal feeder cells and for their eventual application in cell-replacement therapy. Inner cell masses (ICMs) of cultured blastocysts were isolated by immunosurgery and then cultured on mitotically inactivated hUEC feeder layers. Cultured ICMs formed colonies by continuous proliferation and were allowed to proliferate continuously for 40, 50, and 55 passages. The established hES cell lines (Miz-hES-14, -15, and -9, respectively) exhibited typical hES cells characteristics, including continuous growth, expression of specific markers, normal karyotypes, and differentiation capacity. The hUEC feeders have the advantage that they can be used for many passages, whereas MEF feeder cells can only be used as feeder cells for a limited number of passages. The hUECs are available to establish and maintain hES cells, and the high expression of embryotrophic factors and extracellular matrices by hUECs may be important to the efficient growth of hES cells. Clinical applications require the establishment and expansion of hES cells under stable xeno-free culture systems.

Matrix metalloproteinases and their tissue inhibitors in the developing neonatal mouse uterus

Postnatal development of the mouse uterus involves differentiation and development of the endometrial glands as well as the myometrium. Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are involved in extracellular matrix breakdown and morphogenesis of many epitheliomesenchymal organs. As a first step to understanding their roles in postnatal mouse uterine development, MMPs and TIMPs found to be expressed in the neonatal mouse uterus by microarray analysis were localized by in situ hybridization. The MMP-2 mRNA was detected only in the uterine stroma, whereas the MMP-10 mRNA was present only in the uterine epithelium from Postnatal Day (PND) 3 to PND 9. All other MMPs (MMP-11, MMP-14, and MMP-23) as well as TIMP-1, TIMP-2, and TIMP-3 were detected in both epithelial and stromal cells of the endometrium, but not in the myometrium. Uterine extracts were then analyzed by gelatin and casein gel zymography to detect active gelatinases and stromelysins, respectively. Five major gelatinase bands of activity were detected and inhibited by the MMP inhibitors, EDTA or 1,10-phenanthroline, but not by PMSF, a serine protease inhibitor. Western blot analysis confirmed the presence of MMP-2 and MMP-9 proteins in the uterus. Immunoreactive MMP-9 protein was detected only in the endometrial stroma, whereas immunoreactive MMP-2 protein was detected in both the stroma and epithelium of the uterus. Casein zymography detected three major bands of activity ( approximately 54, 63, and 80 kDa) that were inhibited by the serine protease inhibitor, PMSF, but not by the MMP inhibitors, EDTA or 1,10-phenanthroline, suggesting that they were serine proteases. These results support the hypothesis that MMPs and TIMPs regulate postnatal development of the mouse uterus.