A developmental gene regulatory network for C. elegans anchor cell invasion.

Cellular invasion is a key part of development, immunity and disease. Using an in vivo model of Caenorhabditis elegans anchor cell invasion, we characterize the gene regulatory network that promotes cell invasion. The anchor cell is initially specified in a stochastic cell fate decision mediated by Notch signaling. Previous research has identified four conserved transcription factors, fos-1 (Fos), egl-43 (EVI1/MEL), hlh-2 (E/Daughterless) and nhr-67 (NR2E1/TLX), that mediate anchor cell specification and/or invasive behavior. Connections between these transcription factors and the underlying cell biology that they regulate are poorly understood. Here, using genome editing and RNA interference, we examine transcription factor interactions before and after anchor cell specification. Initially, these transcription factors function independently of one another to regulate LIN-12 (Notch) activity. Following anchor cell specification, egl-43, hlh-2 and nhr-67 function largely parallel to fos-1 in a type I coherent feed-forward loop with positive feedback to promote invasion. Together, these results demonstrate that the same transcription factors can function in cell fate specification and differentiated cell behavior, and that a gene regulatory network can be rapidly assembled to reinforce a post-mitotic, pro-invasive state.

Dimerization-driven degradation of C. elegans and human E proteins.

E proteins are conserved regulators of growth and development. We show that the Caenorhabditis elegans E-protein helix-loop-helix-2 (HLH-2) functions as a homodimer in directing development and function of the anchor cell (AC) of the gonad, the critical organizer of uterine and vulval development. Our structure-function analysis of HLH-2 indicates that dimerization drives its degradation in other uterine cells (ventral uterine precursor cells [VUs]) that initially have potential to be the AC. We also provide evidence that this mode of dimerization-driven down-regulation can target other basic HLH (bHLH) dimers as well. Remarkably, human E proteins can functionally substitute for C. elegans HLH-2 in regulating AC development and also display dimerization-dependent degradation in VUs. Our results suggest that dimerization-driven regulation of bHLH protein stability may be a conserved mechanism for differential regulation in specific cell contexts.

Influence of estradiol on bovine trophectoderm and uterine gene transcripts around maternal recognition of pregnancy†.

Embryo survival and pregnancy success is increased among animals that exhibit estrus prior to fixed time-artificial insemination, but there are no differences in conceptus survival to d16. The objective of this study was to determine effects of preovulatory estradiol on uterine transcriptomes, select trophectoderm (TE) transcripts, and uterine luminal fluid proteins. Beef cows/heifers were synchronized, artificially inseminated (d0), and grouped into either high (highE2) or low (lowE2) preovulatory estradiol. Uteri were flushed (d16); conceptuses and endometrial biopsies (n = 29) were collected. RNA sequencing was performed on endometrium. Real-time polymerase chain reaction (RT-PCR) was performed on TE (n = 21) RNA to measure relative abundance of IFNT, PTGS2, TM4SF1, C3, FGFR2, and GAPDH. Uterine fluid was analyzed using 2D Liquid Chromatography with tandem mass spectrometry-based Isobaric tags for relative and absolute quantitation (iTRAQ) method. RT-PCR data were analyzed using the MIXED procedure in SAS. There were no differences in messenger RNA (mRNA) abundances in TE, but there were 432 differentially expressed genes (253 downregulated, 179 upregulated) in highE2/conceptus versus lowE2/conceptus groups. There were also 48 differentially expressed proteins (19 upregulated, 29 downregulated); 6 of these were differentially expressed (FDR < 0.10) at the mRNA level. Similar pathways for mRNA and proteins included: calcium signaling, protein kinase A signaling, and corticotropin-releasing hormone signaling. These differences in uterine function may be preparing the conceptus for improved likelihood of survival after d16 among highE2 animals.

The imbalance of TNF and IL-6 levels and FOXP3 expression at the maternal-fetal interface is involved in adverse pregnancy outcomes in a susceptible murine model of congenital toxoplasmosis.

Vertical transmission of Toxoplasma gondii leads to adverse pregnancy outcomes depending on the time at which the infection occurs and the immunological state of the mother. C57BL/6 and BALB/c mice have been described as susceptible and resistant mouse lineages to congenital T. gondii infection, respectively. This study aimed to elucidate the systemic and local cytokine profile of pregnant mice infected with T. gondii and whether the expression of the transcription factor FOXP3, related to T regulatory cells, is associated with the resistance/susceptibility of these lineages of mice in the context of experimental congenital toxoplasmosis. For this purpose, C57BL/6 and BALB/c females were orally infected with the T. gondii ME-49 strain on the day of vaginal plug detection or day 14 of gestation, examined 7 or 5 days later, respectively, as models of early and late pregnancy. Cytokine levels were measured systemically and in the uterus/placenta. Additionally, the uterus/placenta were evaluated macroscopically for resorption rates and histologically for parasite and FOXP3 immunostaining. The FOXP3 protein expression was also evaluated by western blotting assay. It was found that, during early pregnancy, the infection leads to high IFN-γ, TNF and IL-6 levels systemically, with the TNF levels being higher in C57BL/6 mice. At the maternal-fetal interface, the infection induced high levels of IFN-γ in both mouse lineages; however, higher levels were observed in BALB/c, while high TNF and IL-6 levels were found in C57BL/6, but not in BALB/c mice. In contrast, in late gestation, T. gondii interfered less strongly with the cytokine profile. In early pregnancy, a reduction of FOXP3 expression at the maternal-fetal interface of infected mice was also observed, and the reduction was larger in C57BL/6 compared with BALB/c mice. Additionally, the parasite was seldom found in the uterus/placenta. Thus, the worse pregnancy outcomes observed in C57BL/6 mice were associated with higher TNF systemically, and TNF and IL-6 at the maternal-fetal interface, with lower FOXP3 expression.

New Insights into Development of Female Reproductive Tract-Hedgehog-Signal Response in Wolffian Tissues Directly Contributes to Uterus Development.

The reproductive tract in mammals emerges from two ductal systems during embryogenesis: Wolffian ducts (WDs) and Mullerian ducts (MDs). Most of the female reproductive tract (FRT) including the oviducts, uterine horn and cervix, originate from MDs. It is widely accepted that the formation of MDs depends on the preformed WDs within the urogenital primordia. Here, we found that the WD mesenchyme under the regulation of Hedgehog (Hh) signaling is closely related to the developmental processes of the FRT during embryonic and postnatal periods. Deficiency of Sonic hedgehog (Shh), the only Hh ligand expressed exclusively in WDs, prevents the MD mesenchyme from affecting uterine growth along the radial axis. The in vivo cell tracking approach revealed that after WD regression, distinct cells responding to WD-derived Hh signal continue to exist in the developing FRT and gradually contribute to the formation of various tissues such as smooth muscle, endometrial stroma and vascular vessel, in the mouse uterus. Our study thus provides a novel developmental mechanism of FRT relying on WD.

Epithelial morphogenesis in the perinatal mouse uterus.

BACKGROUND: The uterus is the location where multiple events occur that are required for the start of new life in mammals. The adult uterus contains endometrial or uterine glands that are essential for female fertility. In the mouse, uterine glands are located in the lateral and antimesometrial regions of the uterine horn. Previous three-dimensional (3D)-imaging of the adult uterus, its glands, and implanting embryos has been performed by multiple groups, using fluorescent microscopy. Adenogenesis, the formation of uterine glands, initiates after birth. Recently, we created a 3D-staging system of mouse uterine gland development at postnatal time points, using light sheet fluorescent microscopy. Here, using a similar approach, we examine the morphological changes in the epithelium of the perinatal mouse uterus. RESULTS: The uterine epithelium exhibits dorsoventral (mesometrial-antimesometrial) patterning as early as 3 days after birth (P3), marked by the presence of the dorsally positioned developing uterine rail. Uterine gland buds are present beginning at P4. Novel morphological epithelial structures, including a ventral ridge and uterine segments were identified. CONCLUSIONS: The perinatal mouse uterine luminal epithelium develops dorsal-ventral morphologies at 3 to 4 days postpartum. Between 5 and 6 days postpartum uterine epithelial folds form, defining alternating left-right segments.

Widespread enhancer activation via ERα mediates estrogen response in vivo during uterine development.

Little is known regarding how steroid hormone exposures impact the epigenetic landscape in a living organism. Here, we took a global approach to understanding how exposure to the estrogenic chemical, diethylstilbestrol (DES), affects the neonatal mouse uterine epigenome. Integration of RNA- and ChIP-sequencing data demonstrated that ∼80% of DES-altered genes had higher H3K4me1/H3K27ac signal in close proximity. Active enhancers, of which ∼3% were super-enhancers, had a high density of estrogen receptor alpha (ERα) binding sites and were correlated with alterations in nearby gene expression. Conditional uterine deletion of ERα, but not the pioneer transcription factors FOXA2 or FOXO1, prevented the majority of DES-mediated changes in gene expression and H3K27ac signal at target enhancers. An ERα dependent super-enhancer was located at the Padi gene locus and a topological connection to the Padi1 TSS was documented using 3C-PCR. Chromosome looping at this site was independent of ERα and DES exposure, indicating that the interaction is established prior to ligand signaling. However, enrichment of H3K27ac and transcriptional activation at this locus was both DES and ERα-dependent. These data suggest that DES alters uterine development and consequently adult reproductive function by modifying the enhancer landscape at ERα binding sites near estrogen-regulated genes.

Endocrine Disruption and Reproductive Pathology.

During the past 20 years, investigations involving endocrine active substances (EAS) and reproductive toxicity have dominated the landscape of ecotoxicological research. This has occurred in concert with heightened awareness in the scientific community, general public, and governmental entities of the potential consequences of chemical perturbation in humans and wildlife. The exponential growth of experimentation in this field is fueled by our expanding knowledge into the complex nature of endocrine systems and the intricacy of their interactions with xenobiotic agents. Complicating factors include the ever-increasing number of novel receptors and alternate mechanistic pathways that have come to light, effects of chemical mixtures in the environment versus those of single EAS laboratory exposures, the challenge of differentiating endocrine disruption from direct cytotoxicity, and the potential for transgenerational effects. Although initially concerned with EAS effects chiefly in the thyroid glands and reproductive organs, it is now recognized that anthropomorphic substances may also adversely affect the nervous and immune systems via hormonal mechanisms and play substantial roles in metabolic diseases, such as type 2 diabetes and obesity.

Septate uterus according to ESHRE/ESGE, ASRM and CUME definitions: association with infertility and miscarriage, cost and warnings for women and healthcare systems.

OBJECTIVES: To estimate the differences in frequency of diagnosis of septate uterus using three different definitions and determine whether these differences are significant in clinical practice, and to examine the association between diagnosis of septate uterus, using each of the three definitions, and infertility and/or previous miscarriage as well as the cost of allocation to surgery. METHODS: This was a secondary analysis of data from a prospective study of 261 consecutive women of reproductive age attending a private clinic focused on the diagnosis and treatment of congenital uterine malformations. Reanalysis of the datasets was performed according to three different means of defining septate uterus: following the recommendations of the American Society for Reproductive Medicine (ASRM), a 2016 update of those of the American Fertility Society from 1988 (ASRM-2016: internal fundal indentation depth ≥ 1.5 cm, angle of internal indentation < 90° and external indentation depth < 1 cm); following the recommendations of the European Society of Human Reproduction and Embryology/European Society for Gynaecological Endoscopy (ESHRE/ESGE), published in 2013 and reaffirmed in 2016 (ESHRE/ESGE-2016: internal fundal/uterine indentation depth > 50% of uterine-wall thickness and external indentation depth < 50% of uterine-wall thickness, with uterine-wall thickness measured above interostial/intercornual line); and using a definition published last year which was based on the decision made most often by a group of experts (Congenital Uterine Malformation by Experts; CUME) (CUME-2018: internal fundal indentation depth ≥ 1 cm and external fundal indentation depth < 1 cm). We compared the rate of diagnosis of septate uterus using each of these three definitions and, for each, we estimated the association between the diagnosis and infertility and/or previous miscarriage, and anticipated the costs associated with their implementation using a guesstimation method. RESULTS: Although 32.6% (85/261) of the subjects met the criteria for one of the three definitions of septate uterus, only 2.7% (7/261) of them were defined as having septate uterus according to all three definitions. We diagnosed significantly more cases of septate uterus using ESHRE/ESGE-2016 than using ASRM-2016 (31% vs 5%, relative risk (RR) = 6.7, P < 0.0001) or CUME-2018 (31% vs 12%, RR = 2.6, P < 0.0001) criteria. We also observed frequent cases that could not be classified definitively by ASRM-2016 (gray zone: neither normal/arcuate nor septate; 6.5%). There were no significant differences (P > 0.05) in the prevalence of septate uterus in women with vs those without infertility according to ASRM-2016 (5% vs 4%), ESHRE/ESGE-2016 (35% vs 28%) or CUME-2018 (11% vs 12%). Septate uterus was diagnosed significantly more frequently in women with vs those without previous miscarriage according to ASRM-2016 (11% vs 3%; P = 0.04) and CUME-2018 (22 vs 10%; P = 0.04), but not according to ESHRE/ESGE-2016 (42% vs 28%; P = 0.8) criteria. Our calculations showed that global costs to the healthcare system would be highly dependent on the criteria used in the clinical setting to define septate uterus, with the costs associated with the ESHRE/ESGE-2016 definition potentially being an extra US$ 100-200 billion over 5 years in comparison to ASRM-2016 and CUME-2018 definitions. CONCLUSIONS: The prevalence of septate uterus according to ESHRE/ESGE-2016, ASRM-2016 and CUME-2018 definitions differs considerably. An important limitation of the ASRM classification, which needs to be addressed, is the high proportion of unclassifiable cases originally named, by us, the 'gray zone'. The high rate of overdiagnosis of septate uterus according to ESHRE/ESGE-2016 may lead to unnecessary surgery and therefore unnecessary risk in these women and may impose a considerable financial burden on healthcare systems. Efforts to define clinically meaningful and universally applicable criteria for the diagnosis of septate uterus should be encouraged. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Útero septo según las definiciones de ESHRE/ESGE, ASRM y CUME: la relación con la infertilidad y el aborto espontáneo, el costo y advertencias para las mujeres y los sistemas de salud OBJETIVO: Evaluar el rendimiento de la velocidad sistólica máxima de la arteria cerebral media fetal (MCA-PSV, por sus siglas en inglés) ≥1,5 múltiplos de la mediana (MdM) para la predicción de la anemia moderada-severa en fetos sometidos a transfusión y no sometidos. MÉTODOS: Se realizó una búsqueda sistemática para identificar estudios observacionales relevantes reportados en el período 2008-2018 que evaluaron el rendimiento de la MCA-PSV, utilizando un umbral de 1,5MdM para la predicción de la anemia fetal. El diagnóstico de la anemia fetal mediante la toma de muestras de sangre fue el estándar de referencia. Se utilizaron modelos de efectos aleatorios para la elaboración de una curva jerárquica resumen de las características operativas del receptor (hSROC, por sus siglas en inglés). Se realizaron análisis de subgrupos y metarregresión, según el número de transfusiones intrauterinas previas. RESULTADOS: En el metaanálisis se incluyeron doce estudios y 696 fetos. El área bajo la curva (ABC) hSROC para la anemia moderada-severa fue del 83%. La sensibilidad y especificidad agrupadas (IC 95%) fueron del 79% (70-86%) y 73% (62-82%), respectivamente, y los cocientes de verosimilitud positivos y negativos fueron 2,94 (IC 95%: 2,13-4,00) y 0,272 (IC 95%: 0,188-0,371). Cuando solo se consideraron los fetos no sometidos a transfusión, la predicción mejoró, pues se logró un ABC del 87%, una sensibilidad del 86% (IC 95%: 75-93%) y una especificidad del 71% (IC 95%: 49-87%). Se observó una disminución en la sensibilidad de la predicción de la anemia moderada-severa mediante la MCA-PSV ≥1.5MdM (estimación, -5,5% (IC 95%: -10,7 a -0,3%), P=0,039) en función del aumento del número de transfusiones previas. CONCLUSIONES: El uso de la MCA-PSV ≥1.5MdM para la predicción de la anemia moderada-severa en fetos no sometidos a transfusión muestra una precisión moderada (86% de sensibilidad y 71% de especificidad), que disminuye con el aumento del número de transfusiones intrauterinas.

Retinoic acid signaling determines the fate of uterine stroma in the mouse Müllerian duct.

The Müllerian duct develops into the oviduct, uterus, and vagina, all of which are quite distinct in their morphology and function. The epithelial fate of these female reproductive organs in developing mice is determined by factors secreted from the stroma; however, how stromal differentiation occurs in the female reproductive organs derived from the Müllerian duct is still unclear. In the present study, roles of retinoic acid (RA) signaling in developing female reproductive tracts were investigated. Retinol dehydrogenase 10 (RDH10) and aldehyde dehydrogenase family 1 subfamily A2 (ALDH1A2) mRNAs and proteins and transactivation activity of endogenous RA were found in the stroma of proximal Müllerian ducts and gradually decreased from the proximal to caudal regions in fetal mice. In organ-cultured Müllerian ducts, retinaldehyde or RA treatment induced uterine epithelial differentiation, defined as a layer of columnar epithelial cells negative for oviductal and vaginal epithelial markers. In contrast, inhibition of RA receptor (RAR) signaling induced vaginal epithelial differentiation, characterized as vaginal epithelial marker genes-positive stratified epithelium. Grafting experiments of the organ-cultured Müllerian duct revealed irreversible epithelial fate determination. Although RAR did not directly bind to the homeobox A10 (Hoxa10) promoter region, RA-RAR signaling stimulated Hoxa10 expression. Thus, RA-RAR signaling in the Müllerian duct determines the fate of stroma to form the future uterus and vagina.

Differential Wnt signaling activity limits epithelial gland development to the anti-mesometrial side of the mouse uterus.

In mice, implantation always occurs towards the antimesometrial side of the uterus, while the placenta develops at the mesometrial side. What determines this particular orientation of the implanting blastocyst remains unclear. Uterine glands are critical for implantation and pregnancy. In this study, we showed that uterine gland development and active Wnt signaling activity is limited to the antimesometrial side of the uterus. Dkk2, a known antagonist of Wnt signaling, is only present at the mesometrial side of the uterus. Imaging of whole uterus, thick uterine sections (100-1000µm), and individual glands revealed that uterine glands are simple tubes with branches that are directly connected to the luminal epithelium and are only present towards the antimesometrial side of the uterus. By developing a unique mouse model targeting the uterine epithelium, we demonstrated that Wnt/ß-catenin signaling is essential for prepubertal gland formation and normal implantation, but dispensable for postpartum gland development and regeneration. Our results for the first time have provided a probable explanation for the antimesometrial bias for implantation.

Vaccinia-related kinase 1 is required for early uterine development in Caenorhabditis elegans.

Protein kinases regulate a multitude of processes by reversible phosphorylation of target molecules. Induction of cell proliferation and differentiation are fundamental to development and rely on tightly controlled kinase activities. Vaccinia-Related Kinases (VRKs) have emerged as a multifunctional family of kinases with essential functions conserved, from nematodes and fruit flies, to humans. VRK substrates include chromatin and transcription factors, whereas deregulation of VRKs is implicated in sterility, cancer and neurological defects. In contrast to previous observations, we describe here that Caenorhabditis elegans VRK-1 is expressed in all cell types, including proliferating and post-mitotic cells. Despite the ubiquitous expression pattern, we find that vrk-1 mutants are particularly impaired in uterine development. Our data show that VRK-1 is required for uterine cell proliferation and differentiation. Moreover, the anchor cell, a specialized uterine cell, fails to fuse with neighboring cells to form the utse syncytium in vrk-1 mutants, thus providing further insight on the role of VRKs in organogenesis.

Uterine peristalsis and fertility: current knowledge and future perspectives: a review and meta-analysis.

Although uterine contractions in the non-pregnant uterus have been studied extensively, the knowledge gained has not been used in general fertility treatment work-up. In this review paper, we provide an overview of the current knowledge on uterine peristalsis (UP), based on the available literature. This literature shows that UP influences pregnancy chances in both natural and artificial cycles. Although the physiological background of these contractions is not completely clear, we know that several factors can be of influence, like uterine pathologies and hormones. Several options to alter pregnancy outcome by interfering with uterine contractions have been studied. Our meta-analysis on therapeutic options shows positive results of progesterone at time of embryo transfer in IVF cycles or prostaglandins at time of intrauterine insemination, although the quality of evidence is low. These therapies are probably most beneficial in selected groups of patients with abnormal contraction patterns. The introduction of an objective and user-friendly UP measuring tool suitable for use in daily practice would make it possible to identify and monitor these patients. We suggest that future research should focus on the physiology of initiation of UP and on the development of an effective standard measuring tool.

Clinically Relevant Female Genital Tract Anomalies.

Müllerian anomalies are defined as congenital uterine malformations that arise from improperly developing Müllerian ducts. These malformations have a variety of presentations ranging from asymptomatic to amenorrhea, dyspareunia, dysmenorrhea, chronic pelvic pain, pregnancy loss, fetal malpresentation, placental abruption, and intrauterine growth restriction. In this review, we discuss the clinical implications, diagnosis, and treatment of the various Müllerian anomalies focusing on the ones for which clinical intervention is amenable to improve pregnancy outcomes.

Recombineering-based dissection of flanking and paralogous Hox gene functions in mouse reproductive tracts.

Hox genes are key regulators of development. In mammals, the study of these genes is greatly confounded by their large number, overlapping functions and interspersed shared enhancers. Here, we describe the use of a novel recombineering strategy to introduce simultaneous frameshift mutations into the flanking Hoxa9, Hoxa10 and Hoxa11 genes, as well as their paralogs on the HoxD cluster. The resulting Hoxa9,10,11 mutant mice displayed dramatic synergistic homeotic transformations of the reproductive tracts, with the uterus anteriorized towards oviduct and the vas deferens anteriorized towards epididymis. The Hoxa9,10,11 mutant mice also provided a genetic setting that allowed the discovery of Hoxd9,10,11 redundant reproductive tract patterning function. Both shared and distinct Hox functions were defined. Hoxd9,10,11 play a crucial role in the regulation of uterine immune function. Non-coding non-polyadenylated RNAs were among the key Hox targets, with dramatic downregulation in mutants. We observed Hox cross-regulation of transcription and splicing. In addition, we observed a surprising anti-dogmatic apparent posteriorization of the uterine epithelium. In caudal regions of the uterus, the normal simple columnar epithelium flanking the lumen was replaced by a pseudostratified transitional epithelium, normally found near the more posterior cervix. These results identify novel molecular functions of Hox genes in the development of the male and female reproductive tracts.

Activin-like kinase 2 functions in peri-implantation uterine signaling in mice and humans.

Implantation of a blastocyst in the uterus is a multistep process tightly controlled by an intricate regulatory network of interconnected ovarian, uterine, and embryonic factors. Bone morphogenetic protein (BMP) ligands and receptors are expressed in the uterus of pregnant mice, and BMP2 has been shown to be a key regulator of implantation. In this study, we investigated the roles of the BMP type 1 receptor, activin-like kinase 2 (ALK2), during mouse pregnancy by producing mice carrying a conditional ablation of Alk2 in the uterus (Alk2 cKO mice). In the absence of ALK2, embryos demonstrate delayed invasion into the uterine epithelium and stroma, and upon implantation, stromal cells fail to undergo uterine decidualization, resulting in sterility. Mechanistically, microarray analysis revealed that CCAAT/enhancer-binding protein ß (Cebpb) expression is suppressed during decidualization in Alk2 cKO females. These findings and the similar phenotypes of Cebpb cKO and Alk2 cKO mice lead to the hypothesis that BMPs act upstream of CEBPB in the stroma to regulate decidualization. To test this hypothesis, we knocked down ALK2 in human uterine stromal cells (hESC) and discovered that ablation of ALK2 alters hESC decidualization and suppresses CEBPB mRNA and protein levels. Chromatin immunoprecipitation (ChIP) analysis of decidualizing hESC confirmed that BMP signaling proteins, SMAD1/5, directly regulate expression of CEBPB by binding a distinct regulatory sequence in the 3' UTR of this gene; CEBPB, in turn, regulates the expression of progesterone receptor (PGR). Our work clarifies the conserved mechanisms through which BMPs regulate peri-implantation in rodents and primates and, for the first time, uncovers a linear pathway of BMP signaling through ALK2 to regulate CEBPB and, subsequently, PGR during decidualization.

Lhx1 is required in Müllerian duct epithelium for uterine development.

The female reproductive tract organs of mammals, including the oviducts, uterus, cervix and upper vagina, are derived from the Müllerian ducts, a pair of epithelial tubes that form within the mesonephroi. The Müllerian ducts form in a rostral to caudal manner, guided by and dependent on the Wolffian ducts that have already formed. Experimental embryological studies indicate that caudal elongation of the Müllerian duct towards the urogenital sinus occurs in part by proliferation at the ductal tip. The molecular mechanisms that regulate the elongation of the Müllerian duct are currently unclear. Lhx1 encodes a LIM-homeodomain transcription factor that is essential for male and female reproductive tract development. Lhx1 is expressed in both the Wolffian and Müllerian ducts. Wolffian duct-specific knockout of Lhx1 results in degeneration of the Wolffian duct and consequently the non-cell-autonomous loss of the Müllerian duct. To determine the role of Lhx1 specifically in the Müllerian duct epithelium, we performed a Müllerian duct-specific knockout study using Wnt7a-Cre mice. Loss of Lhx1 in the Müllerian duct epithelium led to a block in Müllerian duct elongation and uterine hypoplasia characterized by loss of the entire endometrium (luminal and glandular epithelium and stroma) and inner circular but not the outer longitudinal muscle layer. Time-lapse imaging and molecular analyses indicate that Lhx1 acts cell autonomously to maintain ductal progenitor cells for Müllerian duct elongation. These studies identify LHX1 as the first transcription factor that is essential in the Müllerian duct epithelial progenitor cells for female reproductive tract development. Furthermore, these genetic studies demonstrate the requirement of epithelial-mesenchymal interactions for uterine tissue compartment differentiation.

Spatial and molecular cues for cell outgrowth during C. elegans uterine development.

The Caenorhabditis elegans uterine seam cell (utse) is an H-shaped syncytium that connects the uterus to the body wall. Comprising nine nuclei that move outward in a bidirectional manner, this synctium undergoes remarkable shape change during development. Using cell ablation experiments, we show that three surrounding cell types affect utse development: the uterine toroids, the anchor cell and the sex myoblasts. The presence of the anchor cell (AC) nucleus within the utse is necessary for proper utse development and AC invasion genes fos-1, cdh-3, him-4, egl-43, zmp-1 and mig-10 promote utse cell outgrowth. Two types of uterine lumen epithelial cells, uterine toroid 1 (ut1) and uterine toroid 2 (ut2), mediate proper utse outgrowth and we show roles in utse development for two genes expressed in the uterine toroids: the RASEF ortholog rsef-1 and Trio/unc-73. The SM expressed gene unc-53/NAV regulates utse cell shape; ablation of sex myoblasts (SMs), which generate uterine and vulval muscles, cause defects in utse morphology. Our results clarify the nature of the interactions that exist between utse and surrounding tissue, identify new roles for genes involved in cell outgrowth, and present the utse as a new model system for understanding cell shape change and, putatively, diseases associated with cell shape change.

Comparison of the ESHRE-ESGE and ASRM classifications of Müllerian duct anomalies in everyday practice.

STUDY QUESTION: Does the European Society of Human Reproduction and Embryology-European Society for Gynaecological Endoscopy (ESHRE-ESGE) classification of female genital tract malformations significantly increase the frequency of septate uterus diagnosis relative to the American Society for Reproductive Medicine (ASRM) classification? SUMMARY ANSWER: Use of the ESHRE-ESGE classification, compared with the ASRM classification, significantly increased the frequency of septate uterus recognition. WHAT IS KNOWN ALREADY: The ESHRE-ESGE criteria were supposed to eliminate the subjective diagnoses of septate uterus by the ASRM criteria and replace the complementary absolute morphometric criteria. However, the clinical value of the ESHRE-ESGE classification in daily practice is difficult to appreciate. The application of the ESHRE-ESGE criteria has resulted in a significantly increased recognition of residual septum after hysteroscopic metroplasty, with a possible risk of overdiagnosis of septate uterus and problems for its management. STUDY DESIGN, SIZE, AND DURATION: A prospective observational study was performed with 261 women consecutively enrolled between June and September 2013. PARTICIPANTS/MATERIALS, SETTING, AND METHODS: Non-pregnant women of reproductive age presented for evaluation to a private medical center. A gynecological examination and 3D ultrasonography were performed to assess the anatomy of the uterus, cervix and vagina. Congenital anomalies were diagnosed using the ASRM classification with additional morphometric criteria as well as with the ESHRE-ESGE classification. We compared the frequency and concordance of diagnoses of septate uterus and all congenital malformations of the uterus according to both classifications. The morphological characteristics of septate uterus recognized by both criteria were compared. MAIN RESULTS AND ROLE OF CHANCE: Of the 261 patients enrolled in this study, septate uterus was diagnosed in 44 (16.9%) and 16 (6.1%) patients using the ESGE-ESHRE and ASRM criteria, respectively [relative risk (RR)ESHRE-ESGE:ASRM 2.74; 95% confidence interval (CI), 1.6-4.72; P < 0.01]. At least one congenital anomaly were diagnosed in 58 (22.2%) and 43 (16.5%) patients using the ESHRE-ESGE and ASRM classifications (RRESHRE-ESGE:ASRM, 1.35; 95% CI, 0.95-1.92, P = 0.1), respectively. The two criteria had moderate strength of agreement in the diagnosis of septate uterus (κ = 0.45, P < 0.01). There was good agreement in differentiation between anomaly and norm between the two assessment criteria (κ = 0.79, P < 0.01). The percentages of all congenital malformations and results of the differentiation between the anomaly and norm were obtained after excluding the confounding original ESHRE-ESGE criterion of dysmorphic uterus (internal indentation <50% uterine wall thickness). The morphology of septa identified by the ESHRE-ESGE [length of internal fundal indentation (mm): median 10.7; lower-upper quartile, 8.1-20] significantly differed (P < 0.01) from that identified by the ASRM criteria [length of internal fundal indentation (mm): median, 21.1; lower-upper quartile, 18.8-33.1]. Internal fundal indentation in 16 out of 44 (36.4%) cases was <1 cm in the septate uterus by ESHRE-ESGE and met the criteria for normal uterus by ASRM. LIMITATIONS AND REASONS FOR CAUTION: The study participants were women who visited a diagnostic and treatment center specialized in uterine congenital malformations for a medical assessment, not from the general public. WIDER IMPLICATIONS OF THE FINDINGS: Septate uterus diagnosis by ESHRE-ESGE was quantitatively dominated by morphological states corresponding to arcuate uterus or cases that were not diagnosed as congenital malformations by ASRM. Relative overdiagnosis of septate uterus by ESHRE-ESGE in these cases may lead to unnecessary overtreatment without the expected benefits. The ESHRE-ESGE classification criteria should be redefined due to confusions in the methodology. Until the criteria are revised, septate uterus should not be diagnosed using this classification system and it should not be used as an eligibility criterion for hysteroscopic metroplasty. STUDY FUNDING/COMPETING INTERESTS: This work was supported by Jagiellonian University (grant no. K/ZDS/003821). The authors have no competing interests to declare.

The potential perinatal origin of placentation disorders in the young primigravida.

The fetus is exposed to high plasma concentrations of unbound estrogens and progesterone throughout pregnancy. However, secretory or decidual changes in the fetal uterus occur relatively infrequently before birth, suggesting a variable endometrial progesterone response at the time of birth. Arguably, partial progesterone resistance that persists into adolescent years may compromise the physiological transformation of the spiral arteries and predispose for defective placentation in the case of pregnancy. Decidualization of the endometrial stromal compartment and junctional zone myometrium precedes trophoblast invasion. It represents the first step in the process of spiral artery remodeling needed to establish effective uteroplacental blood flow by midpregnancy. The major obstetric syndromes caused by impaired placental bed spiral artery remodeling are prevalent in teenage pregnancies, including preeclampsia, fetal growth restriction, and spontaneous preterm labor. Preconditioning of the uterus in response to cyclic menstruation during adolescence may be critical to achieve full uterine responsiveness to hormonal cues. Understanding the mechanisms of functional maturation of the uterus during the early reproductive years may yield novel insights into the major obstetric syndromes.