Mesometrial Decidua Research Articles

Investigation of Phosphatidylcholine by MALDI Imaging Mass Spectrometry in Normal and IVF Early-Stage Embryos.

The receptive phase of the uterus is marked by structural and functional maturation of the endometrium. During this limited time span, the blastocyst competency is superimposed on the receptive endometrium. It is a well-known fact that lipid signalling in early-stage pregnancy has a crucial role in successful embryogenesis. In our study, CD-1 mouse uteri after normal and in vitro fertilization (IVF) were investigated at 6.5, 8.5, and 10.5 days of pregnancy. Matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry and liquid chromatography coupled tandem mass spectrometry were used for identification of phosphatidylcholine (PC) lipid structures. In the embryonal tissues, PC 32:0 and PC 34:0 were increased, while in the antemesometrial (AM) decidua the two 20:4-containing PCs, PC 36:4 and PC 38:4 were increased. In transferred uterus samples, higher expressions of PC 34:0, PC 34:1, PC 34:2, PC 36:1, and PC 36:2 in mesometrial decidua were seen, whereas the two 20:4-containing PCs, PC 36:4 and PC 38:4 showed increased expression in the AM and lateral decidua. This paper shows a significant spatio-temporal change in lipid metabolism during IVF procedures for the first time.

Spatial transcriptomic profiles of mouse uterine microenvironments at pregnancy day 7.5†.

Uterine dysfunctions lead to fertility disorders and pregnancy complications. Normal uterine functions at pregnancy depend on crosstalk among multiple cell types in uterine microenvironments. Here, we performed the spatial transcriptomics and single-cell RNA-seq assays to determine local gene expression profiles at the embryo implantation site of the mouse uterus on pregnancy day 7.5 (D7.5). The spatial transcriptomic annotation identified 11 domains of distinct gene signatures, including a mesometrial myometrium, an anti-mesometrial myometrium, a mesometrial decidua enriched with natural killer cells, a vascular sinus zone for maternal vessel remodeling, a fetal-maternal interface, a primary decidual zone, a transition decidual zone, a secondary decidual zone, undifferentiated stroma, uterine glands, and the embryo. The scRNA-Seq identified 12 types of cells in the D7.5 uterus including three types of stromal fibroblasts with differentiated and undifferentiated markers, one cluster of epithelium including luminal and glandular epithelium, mesothelium, endothelia, pericytes, myelomonocytic cell, natural killer cells, and lymphocyte B. These single-cell RNA signatures were then utilized to deconvolute the cell-type compositions of each individual uterine microenvironment. Functional annotation assays on spatial transcriptomic data revealed uterine microenvironments with distinguished metabolic preferences, immune responses, and various cellular behaviors that are regulated by region-specific endocrine and paracrine signals. Global interactome among regions is also projected based on the spatial transcriptomic data. This study provides high-resolution transcriptome profiles with locality information at the embryo implantation site to facilitate further investigations on molecular mechanisms for normal pregnancy progression.

Sexually dimorphic effects of forkhead box a2 (FOXA2) and uterine glands on decidualization and fetoplacental development

Glands of the uterus are essential for pregnancy establishment. Forkhead box A2 (FOXA2) is expressed specifically in the glands of the uterus and a critical regulator of glandular epithelium (GE) differentiation, development, and function. Mice with a conditional deletion of FOXA2 in the adult uterus, created using the lactotransferrin iCre (Ltf-iCre) model, have a morphologically normal uterus with glands, but lack FOXA2-dependent GE-expressed genes, such as leukemia inhibitory factor (LIF). Adult FOXA2 conditional knockout (cKO; LtfiCre/+Foxa2f/f ) mice are infertile due to defective embryo implantation arising from a lack of LIF, a critical implantation factor of uterine gland origin. However, intraperitoneal injections of LIF can initiate embryo implantation in the uterus of adult FOXA2 cKO mice with pregnancies maintained to term. Here, we tested the hypothesis that FOXA2-regulated genes in the uterine glands impact development of the decidua, placenta, and fetus. On gestational day 8.5, the antimesometrial and mesometrial decidua transcriptome was noticeably altered in LIF-replaced FOXA2 cKO mice. Viable fetuses were reduced in FOXA2 cKO mice on gestational days 12.5 and 17.5. Sex-dependent differences in fetal weight, placenta histoarchitecture, and the placenta and metrial gland transcriptome were observed between control and FOXA2 cKO mice. The transcriptome of the placenta with a female fetus was considerably more altered than the placenta with a male fetus in FOXA2 cKO dams. These studies reveal previously unrecognized sexually dimorphic effects of FOXA2 and uterine glands on fetoplacental development with potential impacts on offspring health into adulthood.

Decidual vascularization during organogenesis after perigestational alcohol ingestion.

Perigestational alcohol consumption up to early organogenesis can produce abnormal maternal vascularization via altered decidual VEGF/receptor expression. CF-1 female mice were administered with 10% ethanol in drinking water for 17 days prior to and up to day 10 of gestation. Control females received water without ethanol. Treated females had reduced frequency of implantation sites with expanded vascular lumen (P < 0.05), α-SMA-immunoreactive spiral arteries in proximal mesometrial decidua, reduced PCNA-positive endothelial cells (P < 0.01) and diminished uterine NK cell numbers (P < 0.05) in proximal decidua compared to controls. The VEGF expression (laser capture microscopy, RT-PCR, western blot and immunohistochemistry) was reduced in decidual tissue after perigestational alcohol consumption (P < 0.05). The uNK-DBA+ cells of treated females had reduced VEGF immunoexpression compared to controls (P < 0.01). Very low decidual and endothelial cell KDR immunoreactivity and reduced decidual gene and protein KDR expression was found in treated females compared to controls (P < 0.001). Instead, strong FLT-1 immunoexpression was detected in decidual and uNK cells (P < 0.05) in the proximal decidua from treated females compared to controls. In conclusion, perigestational alcohol ingestion induces the reduction of lumen expansion of spiral arteries, concomitant with reduced endothelial cell proliferation and uNK cell population, and uncompleted remodeling of the artery smooth muscle. These effects were supported by low decidual VEGF and KDR gene and protein expression and increased FLT-1 expression, suggesting that VEGF and KDR reduction may contribute, in part, to mechanisms involved in deficient decidual angiogenesis after perigestational alcohol consumption in mouse.

A Prolactin Family Paralog Regulates Placental Adaptations to a Physiological Stressor.

The prolactin (PRL) family of hormones and cytokines participates in the regulation of optimal reproductive performance in the mouse and rat. Members of the PRL family are expressed in the anterior pituitary, uterus, and/or placenta. In the present study, we investigated the ontogeny of PRL family 7, subfamily b, member 1 (PRL7B1; also called PRL-like protein-N, PLP-N) expression in the developing mouse placenta and established a mouse model for investigating the biological function of PRL7B1. Transcripts for Prl7b1 were first detected on Gestation Day (d) 8.5. From gestation d8.5 through d14.5, Prl7b1 was expressed in trophoblast cells residing at the interface between maternal mesometrial decidua and the developing placenta. On gestation d17.5, the predominant cellular source of Prl7b1 mRNA was migratory trophoblast cells invading into the uterine mesometrial decidua. The Prl7b1 null mutant allele was generated via replacement of the endogenous Prl7b1 coding sequence with beta-galactosidase (LacZ) reporter and neomycin cassettes. The mutant Prl7b1 allele was successfully passed through the germline. Homozygous Prl7b1 mutant mice were viable and fertile. Under standard animal housing conditions, Prl7b1 had undetectable effects on placentation and pregnancy. Hypoxia exposure during pregnancy evoked adaptations in the organization of the wild-type placenta that were not observed in Prl7b1 null placentation sites. In summary, PRL7B1 is viewed as a part of a pathway regulating placental adaptations to physiological stressors.

Control of regional decidualization in implantation: Role of FoxM1 downstream of Hoxa10 and cyclin D3.

Appropriate regulation of regional uterine stromal cell decidualization in implantation, at the mesometrial triangle and secondary decidual zone (SDZ) locations, is critical for successful pregnancy, although the regulatory mechanisms remain poorly understood. In this regard, the available animal models that would specifically allow mechanistic analysis of site-specific decidualization are strikingly limited. Our study found that heightened expression of FoxM1, a Forkhead box transcription factor, is regulated during decidualization, and its conditional deletion in mice reveals failure of implantation with regional decidualization defects such as a much smaller mesometrial decidua with enlarged SDZ. Analysis of cell cycle progression during decidualization both in vivo and in vitro demonstrates that the loss of FoxM1 elicits diploid cell deficiency with enhanced arrests prior to mitosis and concomitant upregulation of polyploidy. We further showed that Hoxa10 and cyclin D3, two decidual markers, control transcriptional regulation and intra-nuclear protein translocation of FoxM1 in polyploid cells, respectively. Overall, we suggest that proper regional decidualization and polyploidy development requires FoxM1 signaling downstream of Hoxa10 and cyclin D3.

Influence of type 1 diabetes on the extracellular matrix of the vascular region of mesometrial decidua in mice

Influence of type 1 diabetes on the extracellular matrix of the vascular region of mesometrial decidua in mice

Embryo mortality in Isg15-/- mice is exacerbated by environmental stress.

The interferon-stimulated gene 15 (Isg15) encodes a ubiquitin-like protein that is induced in the endometrium by pregnancy in mice, humans, and ruminants. Because ISG15 is a component of the innate immune system, we hypothesized that development of the embryo, fetus, and postnatal pup may be impaired in mice lacking Isg15 (Isg15(-/-)) and that this development would be further impaired in response to environmental insults such as hypoxia. The number of implantation sites, resorption sites, dead embryos, and the changes in overall gross morphology of the uterus were evaluated in Isg15(-/-) mice on Days 7.5 and 12.5 postcoitum (dpc). Postnatal development also was monitored from birth to 12 wk of age. On 7.5 dpc, the number of implantation sites and serum progesterone concentrations were similar. However, embryo mortality increased (P < 0.05) in Isg15(-/-) dams by 12.5 dpc, resulting in smaller litter sizes (4.26 ± 0.21 embryos; n = 83 litters) compared to Isg15(+/+) females (7.78 ± 0.29 pups; n = 47 litters). Embryo mortality in Isg15(-/-) mice was further exacerbated to 70% when dams were stressed through housing under hypoxic conditions (PB = 445 mmHg; 6.5-12.5 dpc). Transmission electron microscopy revealed lesions in antimesometrial decidua as well as trophoblast cells adjacent to decidual cells on 7.5 dpc. ISG15 was localized to mesometrial decidua on 7.5 dpc. By 12.5 dpc, ISG15 was intensely localized to the labyrinth of the placenta. By 7.5 dpc, uterine natural killer cell migration into the mesometrial pole was diminished by 65% and was less prevalent in Isg15(-/-) compared to Isg15(+/+) deciduum. Postnatal growth rate of offspring that survived to birth from Isg15(-/-) and Isg15(+/+) dams was not different. Embryo mortality occurs in pregnant Isg15(-/-) mice, is exacerbated by environmental insults like maternal hypoxia, and might result from impaired early decidualization, vascular development, and formation of the labyrinth.

Decidual Angiogenesis and Placental Orientation Are Altered in Mice Heterozygous for a Dominant Loss-of-Function Gja1 (Connexin43) Mutation1

Connexin43 (CX43), encoded by Gja1 in the mouse, is highly expressed in decidual cells and is known to be important for the transformation of stromal cells into the compact decidua and for neoangiogenesis. Here we investigated if the dominant Gja1(Jrt) mutation encoding CX43(G60S) in mice, which results in a phenotype resembling oculodentodigital dysplasia in humans, has an impact on decidualization, angiogenesis, and implantation. We found a reduced mean weight of fetuses at Gestational Day 17.5 in dams carrying this mutation, with the growth deficiency being independent of fetal genotype. Although the mutant implantation sites exhibited a reduction in CX43 protein, with most immunoreactivity being cytoplasmic, the decidua was morphologically intact at Embryonic Days 5.5 to 7.5. However, the mutation resulted in enhanced and irregular angiogenesis and an increased level of expression of the angiogenic factor-encoding genes Vegfa, Flt1, Kdr, and Fgf2 as well as the prolactin-related gene Prl6a. Moreover, immunolocalization of VEGFA, FLT1, and KDR revealed a homogeneous distribution pattern in the mesometrial as well as antimesometrial decidua of the mutants. Most obviously, uterine NK cells are drastically diminished in the mesometrial decidua of the mutant mice. Invasion of ectoplacental cone cells was disoriented, and placentation was established more laterally in the implantation chambers. It was concluded that the CX43(G60S) mutant impairs control of decidual angiogenesis, leading to dysmorphic placentation and fetal growth restriction. This phenomenon could contribute to the reduced fetal weights and viability of pups born of Gja1(Jrt)/+ dams.

Morphology of the mouse mesometrial decidua during early pregnancy

Morphology of the mouse mesometrial decidua during early pregnancy

Widespread DNA hypomethylation at gene enhancer and low CpG density regions in placentas associated with early-onset preeclampsia

s / Placenta 34 (2013) A1–A99 A86 P2.88. WIDESPREAD DNA HYPOMETHYLATION AT GENE ENHANCER AND LOW CPG DENSITY REGIONS IN PLACENTAS ASSOCIATEDWITH EARLY-ONSET PREECLAMPSIA John Blair , Ryan Yuen , Brendan Lim , Deborah McFadden , Peter von Dadelszen , Wendy Robinson 1 University of British Columbia, Vancouver, BC, Canada; University of Toronto, Toronto, ON, Canada Preeclampsia is a serious complication of pregnancy that can affect both maternal and fetal outcomes. Early-onset preeclampsia (EOPET) is a severe form of preeclampsia that is associated with altered physiological characteristics and gene expression in the placenta. DNA methylation is a relatively stable epigenetic modification to DNA that can reflect gene expression, and can provide insight into the mechanisms underlying such expression changes. Objectives: We sought to profile DNA methylation changes in EOPET to better characterize the pathology underlying this condition and the relationship to clinical features. Methods: DNA methylation was profiled in placentas from 20 EOPET and 20-gestational age matched control pregnancies using the Infinium HumanMethylation450 Beadchip. This analysis was followed up using the HT-12v4 Expression BeadChip microarray, bisulfite pyrosequencing and bioinformatic analysis. Results: We identified 38,840 CpG sites with significant (FDR 12.5% methylation difference compared to the gestational age-matched normotensive controls. Significant sites were enriched at the enhancers and low CpG density regions of the associated genes and the majority (74.5%) of these sites were hypomethylated in EOPET. No stratification of the EOPET DNA methylation profile was apparent based on presence/absence of intrauterine growth restriction (IUGR) or severe proteinuria. CpG sites from four genes relevant to preeclampsia (INHBA, BHLHE40, SLC2A1, and ADAM12) were followed up using bisulfite pyrosequencing in a larger cohort, and they showed different extent of changes in related pregnancy disorders (late-onset preeclampsia (LOPET) and normotensive IUGR (nIUGR)). Genome-wide expression in a subset of samples showed that some of the gene expression changes were negatively correlated with DNA methylation changes, particularly for genes that are responsible for angiogenesis (such as EPAS1 and FLT1). Conclusion: Based on DNA methylation profiling, we conclude that there are widespread DNA methylation alterations in EOPET that may be associated with changes in placental function. This property may provide a useful tool for early screening of such placentas. http://dx.doi.org/10.1016/j.placenta.2013.06.254 P2.89. MORPHOLOGY OF THE MOUSE MESOMETRIAL DECIDUA DURING EARLY PREGNANCY Alex Kors Vidsiunas , Sergio Ferreira de Oliveira 2 Nove de Julho University, Sao Paulo-SP, Brazil; University of Sao Paulo, Sao

STAT3 and SOCS3 expression patterns during murine placenta development

Signal transducers and activators of transcription 3 (STAT3) has been identified as an important signal transducer in the invasive phenotype of the trophoblasts cells in in vitro studies. However, the in situ distribution and patterns of expression of this molecule in trophoblast cells during the development of the placenta are still under-elucidated. Mice uteri of gestational ages between 7 and 14 days of pregnancy (dop) were fixed in methacarn and processed with immunoperoxidase techniques for detection of STAT3 and its phosphorylation at serine (p-ser727) residues, as well as the suppressor of cytokine signaling 3 (SOCS3) expression. STAT3 was observed at 7 through 9 dop in both the antimesometrial and mesometrial deciduas, while continued immunoreactivity between 10 and 13 dop was seen only in the mesometrial decidua. In the placenta, STAT3 was detected in the cytotrophoblast cells of labyrinth and giant trophoblast cells between 10 and 14 dop. Immunoreactivity for STAT3 was also seen in trophoblast cells surrounding the maternal blood vessels. On days 10 and 11 of pregnancy, p-ser727 was detectable in the mesometrial decidua and in giant trophoblasts, while during 12-14 dop in the spongiotrophoblast region. In addition, SOCS3 was immunodetected in maternal and placental tissues, principally in the giant trophoblast cells during the whole period of the study. The present in situ study shows the distribution of STAT3, its serine activation and SOCS3 in different maternal and fetal compartments during murine placental development, thus further supporting the idea that they play a role during physiological placentation in mice.

Matrix metalloproteinase expression and activity in trophoblast-decidual tissues at organogenesis in CF-1 mouse

During early placentation, matrix metalloproteinases (MMPs) play important roles in decidualization, trophoblast migration, invasion, angiogenesis, vascularization and extracellular matrix (ECM) remodeling of the endometrium. The aim of our study was to analyze the localization, distribution and differential expression of MMP-2 and -9 in the organogenic implantation site and to evaluate in vivo and in vitro decidual MMP-2 and -9 activities on day 10 of gestation in CF-1 mouse. Whole extracts for Western blotting of organogenic E10-decidua expressed MMP-2 and -9 isoforms. MMP-2 immunoreactivity was found in a granular and discrete pattern in ECM of mesometrial decidua (MD) near maternal blood vessels and slightly in non-decidualized endometrium (NDE). Immunoexpression of MMP-9 was also detected in NDE, in cytoplasm of decidual cells and ECM of vascular MD, in trophoblastic area and in growing antimesometrial deciduum. Gelatin zymography showed that MMP-9 activity was significantly lower in CM compared to the active form of direct (not cultured) and cultured decidua. The decidual active MMP-9 was significantly higher than the active MMP-2. These results show differential localization, protein expression and enzymatic activation of MMPs, suggesting specific roles for MMP-2 and MMP-9 in decidual and trophoblast tissues related to organogenic ECM remodeling and vascularization during early establishment of mouse placentation.

Modulation of the novel cannabinoid receptor - GPR55 - during rat fetoplacental development

Decidualization process involves the morphological and functional transformation of endometrial stromal cells into decidual cells. This is a finely regulated process, which involves proliferation and differentiation of stromal cells into decidual cells, which is followed by regression of the decidual tissue, mainly by apoptosis, necessary to accommodate the growing embryo. Together with the endogenous cannabinoids (ECs) and the respective metabolizing-enzymes, the cannabinoid receptors complete the endocannabinoid system (ECS). Two cannabinoid receptors have been described so far, CB1 and CB2, though a third has been suggested, CB3. Although the ECS role in several biological functions, including reproductive processes, is now well documented, the current state of knowledge about this system is still incomplete. In order to investigate the expression of GPR55, referred as the novel cannabinoid receptor 3 (CB3), in the uterine maternal tissues during normal pregnancy we analysed its expression by Q-PCR, Western blot and immunohistochemistry during fetoplacental period. We found higher protein levels on day 14, after full development of mesometrial decidua. In addition, GPR55 was found in uterine natural killer (uNK) cells pointing to an involvement in the immunological reactions that occur during pregnancy. The prominent expression of GPR55 in decidual cells suggests a role in mediating cannabinoid signalling during fetoplacental development. Additionally, we have studied the effects resulting from its activation in primary decidual cell cultures, which revealed a potential modulation of cell viability through GPR55. The data presented here may clarify the role of GPR55 in fetoplacental development and highlights the presence of a new target for cannabinoid signalling during pregnancy.

Ovarian Steroid Receptors and Activated MAPK in the Regional Decidualization in Rats1

Though the decidua serves a critical function in implantation, the hormonal regulated pathway in decidualization is still elusive. Here we describe in detail the regional distribution and the effects of progesterone receptors (PGR), estrogen receptors (ESR), and MAPK activation on decidualization. We showed an increase in PGR A, PGR B, ESR1, and phosphorylated MAPK3-1 proteins (p-MAPK3-1), but not in ESR2, in the decidual tissue up to Day 8 of pregnancy. PGR was predominantly found in the nuclei of mesometrial decidual cells and of undifferentiated stromal cells where it colocalizes with ESR2 and ESR1. In the antimesometrial decidua, all the receptors showed cytoplasmic localization. MAPK was activated exclusively in undifferentiated stromal cells of the junctional zone between the antimesometrial and mesometrial decidua and at the border of the antimesometrial decidua. Treatment with the progesterone antagonist onapristone and/or the estrogen antagonist faslodex reduced the extent of decidual tissue and downregulated the levels of PGR and ESR1. The expression level of ESR2 was affected only by the progesterone receptor antagonist, while neither the antiprogestin nor the antiestrogen significantly modified the p-MAPK3-1 level. The inhibition of MAPK3-1 phosphorylation by PD98059 impaired the extent of decidualization and the closure reaction of the implantation chamber, and significantly downregulated ESR1. These results confirm a role of both steroid receptors in the growth and differentiation of the different decidual regions and suggest a new function for p-MAPK3-1 in regulating expression levels of ESR1, thereby maintaining the proliferation capacity of stromal cells and limiting the differentiation process in specified regions of decidual tissues.

The endocannabinoid 2-arachidonoylglycerol (2-AG) and metabolizing enzymes during rat fetoplacental development: A role in uterine remodelling

The main endocannabinoids (EC) identified in mammalian tissues are N-arachidonoylethanolamide (AEA, anandamide), and 2-arachidonoylglycerol (2-AG). AEA levels are critical in pregnancy, especially during implantation, decidualization, and placental development. As 2-AG functions in pregnancy are still largely undefined, we hypothesized that it may also have a role during fetoplacental development. We showed that 2-AG is not only present in the rat mesometrial decidua and plasma during fetoplacental development, but that both 2-AG synthesizing (diacylglycerol lipase) and degradation (monoacylglycerol lipase) enzymes are expressed by decidual cells. While lower concentrations of 2-AG induced apoptosis of rat primary decidual cells, via the CB1 receptor, higher concentrations induced a dramatic effect on cell morphology, cell viability and lactate dehydrogenase release, triggered through a mechanism independent of CB1. This study provides evidences that 2-AG fluctuation in maternal tissues throughout normal pregnancy is primarily regulated by its metabolizing enzymes. Together, these data supports the hypothesis that a deregulation of the endocannabinoid system through aberrant cannabinoid signalling may impact normal uterine remodelling process and consequently normal pregnancy.

Wnt Genes in the Mouse Uterus: Potential Regulation of Implantation1

Wnt genes are involved in critical developmental and growth processes. The present study comprehensively analyzed temporal and spatial alterations in Wnt and Fzd gene expression in the mouse uterus during peri-implantation of pregnancy. Expression of Wnt4, Wnt5a, Wnt7a, Wnt7b, Wnt11, Wnt16, Fzd2, Fzd4, and Fzd6 was detected in the uterus during implantation. Wnt4 mRNA was most abundant in the decidua, whereas Wnt5a mRNA was restricted to the mesometrial decidua during decidualization. Wnt7a, Wnt7b, and Wnt11 mRNAs were abundantly detected in the endometrial epithelia. The expression of Wnt7b was robust in the luminal epithelium (LE) at the implantation site on Gestational Day 5, whereas Wnt11 mRNA disappeared in the LE adjacent to the embryo in the antimesometrial implantation chamber but remained abundant in the LE. Wnt16 mRNA was localized to the stroma surrounding the LE on Day 4 and remained in the stroma adjacent to the LE but not in areas undergoing the decidual reaction. Fzd2 mRNA was detected in the decidua, Fzd4 mRNA was in the vessels and stroma surrounding the embryo, and Fzd6 mRNA was observed in the endometrial epithelia, stroma, and some blood vessels during implantation. Ovarian steroid hormone treatment was found to regulate Wnt genes and Fzd receptors in ovariectomized mice. Especially, single injections of progesterone stimulated Wnt11 mRNA, and estrogen stimulated Wnt4 and Wnt7b. The temporal and spatial alterations in Wnt genes likely play a critical role during implantation and decidualization in mice.

IL11 Antagonist Inhibits Uterine Stromal Differentiation, Causing Pregnancy Failure in Mice1

Hormonal contraceptives are unsuitable for many women; thus, the development of new, nonhormonal contraceptives is of great interest. In women, uterine epithelial expression of interleukin 11 (IL11) and its receptor (IL11RA) suggests IL11 is critical for blastocyst attachment during implantation. Il11ra-deficient mice are infertile due to a defective decidualization response to the blastocyst, leading to total pregnancy loss. We examined the effect of administering a PEGylated IL11 antagonist, PEGIL11A (where PEG is polyethylene glycol), on pregnancy outcomes in mice and IL11 signaling in human endometrial epithelial cells (HES). PEGIL11A was detected in sera up to 72 h after intraperitoneal (IP) injection versus up to 2 h for the non-PEGylated antagonist. Following IP injection, PEGIL11A localized to uterine decidual cells and reduced immunoreactive cyclin D3 (IL11 decidual target). To inhibit IL11 action during early decidualization, PEGIL11A or control were administered IP on Days 3-6 (beginning just prior to maximal decidual Il11 expression). On Day 6, mesometrial decidualization was disturbed in PEGIL11A-treated animals with regions of hemorrhage visible in the mesometrial decidua. On Day 10, severe decidual destruction was visible: implantation sites contained significant hemorrhage, and the uterine luminal epithelium had reformed, suggesting a return to estrous cycling. These results demonstrate that PEGIL11A blocked IL11 action in the decidua during early decidualization, which totally abolished pregnancy and which is equivalent to the Il11ra(-/-) mouse. PEGIL11A significantly diminished STAT3 phosphorylation in HES cells in vitro (P < or = 0.05). This study provides valuable information for PEGIL11A that could lead to the development of this protein as a nonhormonal contraceptive.

Time-Course Analyses Addressing the Acquisition of DBA Lectin Reactivity in Mouse Lymphoid Organs and Uterus During the First Week of Pregnancy

Terminal differentiation of uterine natural killer (uNK) cells is induced in humans and mice at the time of endometrial decidualization. In mice, commitment to this lineage is first recognized at gestation day (gd)5.5 when small, non-granulated lymphocytes in the mesometrial decidua basalis become histochemically reactive with the lectin Dolichlos biflorus agglutinin (DBA). Transplantation experiments in mice have shown that the self-renewing progenitors of uNK cells are present in peripheral rather than uterine tissues. While lymphoid tissues of virgin mice lack DBA lectin reactive putative uNK cell precursors or progenitors, peripheral organs have not been systematically examined in female mice during early pregnancy while the uNK cell population is becoming established. Here we report such a study in gd0.5–7.5 random bred mice. Only mesenteric lymph nodes showed a transient gain in DBA lectin reactive lymphocytes between gd0.5 and 4.5. These cells had cytoplasmic but almost no surface DBA lectin reactivity. This study indicates that the decidual environment is unique and locally promotes DBA lectin surface expression in terminally differentiating uNK cells.

Stage-specific Integration of Maternal and Embryonic Peroxisome Proliferator-activated Receptor δ Signaling Is Critical to Pregnancy Success

Successful pregnancy depends on well coordinated developmental events involving both maternal and embryonic components. Although a host of signaling pathways participate in implantation, decidualization, and placentation, whether there is a common molecular link that coordinates these processes remains unknown. By exploiting genetic, molecular, pharmacological, and physiological approaches, we show here that the nuclear transcription factor peroxisome proliferator-activated receptor (PPAR) delta plays a central role at various stages of pregnancy, whereas maternal PPARdelta is critical to implantation and decidualization, and embryonic PPARdelta is vital for placentation. Using trophoblast stem cells, we further elucidate that a reciprocal relationship between PPARdelta-AKT and leukemia inhibitory factor-STAT3 signaling pathways serves as a cell lineage sensor to direct trophoblast cell fates during placentation. This novel finding of stage-specific integration of maternal and embryonic PPARdelta signaling provides evidence that PPARdelta is a molecular link that coordinates implantation, decidualization, and placentation crucial to pregnancy success. This study is clinically relevant because deferral of on time implantation leads to spontaneous pregnancy loss, and defective trophoblast invasion is one cause of preeclampsia in humans.