Integrated microRNA and secretome analysis of human endometrial organoids reveal the miR-3194-5p/Aquaporin/S100A9 module in regulating trophoblast functions

Successful placentation requires delicate communication between the endometrium and trophoblasts. The invasion and integration of trophoblasts into the endometrium during early pregnancy is crucial to placentation. Dysregulation of these functions is associated with various pregnancy complications, such as miscarriage and preeclampsia. The endometrial microenvironment has an important influence on trophoblast cell functions. The precise effect of the endometrial gland secretome on trophoblast functions remains uncertain. We hypothesized that the hormonal environment regulates the miRNA profile and secretome of the human endometrial gland, which subsequently modulates trophoblast functions during early pregnancy. Human endometrial tissues were obtained from endometrial biopsies with written consent. Endometrial organoids were established in matrix gel under defined culture conditions. They were treated with hormones mimicking the environment of the proliferative phase (Estrogen, E2), secretory phase (E2+Progesterone, P4), and early pregnancy (E2+P4+Human Chorionic Gonadotropin, hCG). miRNA-seq was performed on the treated organoids. Organoid secretions were also collected for mass spectrometric analysis. The viability and invasion/migration of the trophoblasts after treatment with the organoid secretome were determined by cytotoxicity assay and transwell assay, respectively. Endometrial organoids with the ability to respond to sex steroid hormones were successfully developed from human endometrial glands. By establishing the first secretome profiles and miRNA atlas of these endometrial organoids to the hormonal changes followed by trophoblast functional assays, we demonstrated that sex steroid hormones modulate aquaporin (AQP)1/9 and S100A9 secretions through miR-3194 activation in endometrial epithelial cells, which in turn enhanced trophoblast migration and invasion during early pregnancy. By using a human endometrial organoid model, we demonstrated for the first time that the hormonal regulation of the endometrial gland secretome is crucial to regulating the functions of human trophoblasts during early pregnancy. The study provides the basis for understanding the regulation of early placental development in humans.

Establishment of Adenomyosis Organoids as a Preclinical Model to Study Infertility

Adenomyosis is related to infertility and miscarriages, but so far there are no robust in vitro models that reproduce its pathological features to study the molecular mechanisms involved in this disease. Endometrial organoids are in vitro 3D models that recapitulate the native microenvironment and reproduce tissue characteristics that would allow the study of adenomyosis pathogenesis and related infertility disorders. In our study, human endometrial biopsies from adenomyosis (n = 6) and healthy women (n = 6) were recruited. Organoids were established and hormonally differentiated to recapitulate midsecretory and gestational endometrial phases. Physiological and pathological characteristics were evaluated by immunohistochemistry, immunofluorescence, qRT-PCR, and ELISA. Secretory and gestational organoids recapitulated in vivo glandular epithelial phenotype (pan-cytokeratin, Muc-1, PAS, Laminin, and Ki67) and secretory and gestational features (α-tubulin, SOX9, SPP1, PAEP, LIF, and 17βHSD2 expression and SPP1 secretion). Adenomyosis organoids showed higher expression of TGF-β2 and SMAD3 and increased gene expression of SPP1, PAEP, LIF, and 17βHSD2 compared with control organoids. Our results demonstrate that organoids derived from endometria of adenomyosis patients and differentiated to secretory and gestational phases recapitulate native endometrial-tissue-specific features and disease-specific traits. Adenomyosis-derived organoids are a promising in vitro preclinical model to study impaired implantation and pregnancy disorders in adenomyosis and enable personalized drug screening.

Pluripotent stem cell-derived endometrial stromal fibroblasts in a cyclic, hormone-responsive, coculture model of human decidua

Various human diseases and pregnancy-related disorders reflect endometrial dysfunction. However, rodent models do not share fundamental biological processes with the human endometrium, such as spontaneous decidualization, and no existing human cell cultures recapitulate the cyclic interactions between endometrial stromal and epithelial compartments necessary for decidualization and implantation. Here we report a protocol differentiating human pluripotent stem cells into endometrial stromal fibroblasts (PSC-ESFs) that are highly pure and able to decidualize. Coculture of PSC-ESFs with placenta-derived endometrial epithelial cells generated organoids used to examine stromal-epithelial interactions. Cocultures exhibited specific endometrial markers in the appropriate compartments, organization with cell polarity, and hormone responsiveness of both cell types. Furthermore, cocultures recapitulate a central feature of the human decidua by cyclically responding to hormone withdrawal followed by hormone retreatment. This advance enables mechanistic studies of the cyclic responses that characterize the human endometrium.

From Snapshots to Development: Identifying the Gaps in the Development of Stem Cell-based Embryo Models along the Embryonic Timeline

In recent years, stem cell-based models that reconstruct mouse and human embryogenesis have gained significant traction due to their near-physiological similarity to natural embryos. Embryo models can be generated in large numbers, provide accessibility to a variety of experimental tools such as genetic and chemical manipulation, and confer compatibility with automated readouts, which permits exciting experimental avenues for exploring the genetic and molecular principles of self-organization, development, and disease. However, the current embryo models recapitulate only snapshots within the continuum of embryonic development, allowing the progression of the embryonic tissues along a specific direction. Hence, to fully exploit the potential of stem cell-based embryo models, multiple important gaps in the developmental landscape need to be covered. These include recapitulating the lesser-explored interactions between embryonic and extraembryonic tissues such as the yolk sac, placenta, and the umbilical cord; spatial and temporal organization of tissues; and the anterior patterning of embryonic development. Here, it is detailed how combinations of stem cells and versatile bioengineering technologies can help in addressing these gaps and thereby extend the implications of embryo models in the fields of cell biology, development, and regenerative medicine.

Expression of bone morphogenetic protein 10 in cases with endometrial carcinoma and its clinical significance

PURPOSE

To investigate the expression of bone morphogenetic protein 10 (BMP-10) in patients with endometrial carcinoma (EC) and its clinical significance.

METHODS

Totally 143 cancer tissue specimens were sampled from patients with EC and retrospectively analyzed. The immunohistochemical method was adopted for quantifying BMP-10 in EC tissues. Then the patients were assigned to high and low BMP-10 expression groups. The Kaplan-Meier method and log-rank test were adopted to compare the difference of tumor-free survival (TFS) rate and overall survival (OS) rate between the two groups. The COX proportional hazard model was used to analyze independent risk factors affecting the TFS rate and OS rate of patients with EC.

RESULTS

There were 80 patients (55.94%) with low BMP-10 expression and 63 patients with high BMP-10 expression (54.06%). BMP-10 expression was significantly correlated with International Federation of Gynecology and Obstetrics (FIGO) stage (P = 0.001), myometrial invasion depth (P < 0.001), histological grade (P < 0.001), and lymph node metastasis (P = 0.009). Additionally, TFS rate (P = 0.004) and OS rate (P = 0.003) in the low BMP-10 expression group were notably lower than those in the high BMP-10 expression group. Multivariate analysis showed that BMP-10 expression (HR: 13.712, 95% CI 1.823-103.158, P = 0.011) was an independent risk factor for the TFS of patients with EC. FIGO stage (P = 0.001) and BMP-10 expression (HR: 8.655, 95% CI 1.098-68.215, P = 0.020) were independent risk factors for the OS of such patients.

CONCLUSIONS

BMP-10 can be adopted as a molecular marker for predicting the poor prognosis of patients with EC.

Endometrial Organoids: A Rising Star for Research on Endometrial Development and Associated Diseases

The endometrium is one of the most dynamic organs in the human body. Until now, cell lines have furthered the understanding of endometrial biology and associated diseases, but they failed to recapitulate the key physiological aspects of the endometrium, especially as it relates to its complex architecture and functions. Organoid culture systems have become an alternative approach to reproduce biological functions of tissues in vitro. Endometrial organoids have now been established from stem/progenitor cells and/or differentiated cells by several methods, which represents a promising tool to gain a deeper understanding of this dynamic organ. In this review, we will discuss the establishment, characteristics, applications, and potential challenges and directions of endometrial organoids.

Metformin regulation of progesterone receptor isoform-B expression in human endometrial cancer cells is glucose-dependent

Metformin (MET) constitutes the first-line treatment against type 2 diabetes. Growing evidence linking insulin resistance and cancer risk has expanded the therapeutic potential of MET to several cancer types. However, the oncostatic mechanisms of MET are not well understood. MET has been shown to promote the expression of progesterone receptor (PGR) and other antitumor biomarkers in patients with non-diabetic endometrial cancer (EC) and in Ishikawa EC cells cultured in normal glucose (5.5 mM) media. Therefore, the present study aimed to assess the effects of MET on EC cells under conditions simulating diabetes. Ishikawa cells treated with 10 nM 17β-estradiol (E2) and/or 100 µM MET and exposed to normal and high (17.5 mM) concentrations of glucose were evaluated for proliferative and PGR expression status. Under normal glucose conditions, MET attenuated E2-induced cell proliferation and cyclin D1 gene expression, and increased total PGR and PGR-B transcript levels. MET inhibited Ishikawa cell spheroid formation only in the absence of E2 treatment. In E2-treated cells under high glucose conditions, MET showed no effects on cell proliferation and spheroid formation, and increased total PGR but not PGR-B transcript levels. Transfection with Krüppel-like factor 9 small interfering RNA increased PGR-A transcript levels, irrespective of glucose environment. Medroxyprogesterone acetate downregulated PGR-A expression more effectively with metformin under high compared with normal glucose conditions. To evaluate the potential mechanisms underlying the targeting of PGR by MET, E2-treated cells were incubated with MET and the AMPK inhibitor Compound C, or with the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), under normal glucose conditions. Compound C abrogated the effects of MET on PGR-B while AICAR increased PGR-B transcript levels, albeit less effectively compared with MET. The present results demonstrate the glucose-dependent effects of MET on PGR-B isoform expression, which may inform the response to progestin therapy in diabetic women with EC.

Microphysiological Modeling of the Human Endometrium

Since the beginning of clinical medicine, the human uterus has held the fascination of clinicians and researchers, given its critical role in the reproduction of our species. The endometrial lining provides residence for the embryo; however, this symbiotic interaction can be disrupted if the timing is not correct and the endometrium is not receptive. Diseases associated with the endometrium interfere with the reproductive process and cause a life-altering burden of pain and even death. With the advancement of technologies and new insights into the biology of the endometrium, much has been uncovered about the dynamic and essential changes that need to occur for normal endometrial function, as well as aberrations that lead to endometrial diseases. As expected, the more that is uncovered, the more the complexity of the endometrium is made evident. In this study, we bring together three areas of scientific advancement that remain in their infancy, but which together have the potential to mirror this complexity and enable understanding. Studies on induced pluripotent stem cells, three-dimensional tissue mimics, and microfluidic culture platforms will be reviewed with a focus on the endometrium. These unconventional approaches will provide new perspectives and appreciation for the elegance and complexity of the endometrium. Impact statement The ability of the human endometrium to regenerate on a monthly basis for ∼4 decades of reproductive years exemplifies its complexity as well as its susceptibility to disease. Restrictions on the types of research that can be done in the human endometrium motivate the development of new technologies and model systems. The three areas of technological advancement reviewed here-induced pluripotent stem cells, three-dimensional model systems, and microfluidic culture systems-will highlight some of the tools that can be applied to studying the human endometrium in ways that have not been done before.

Development of A 3D Tissue Slice Culture Model for the Study of Human Endometrial Repair and Regeneration

The human endometrium undergoes sequential phases of shedding of the upper functionalis zone during menstruation, followed by regeneration of the functionalis zone from the remaining basalis zone cells, and secretory differentiation under the influence of the ovarian steroid hormones estradiol (E2) and progesterone (P4). This massive tissue regeneration after menstruation is believed to arise from endometrial stromal and epithelial stem cells residing in the basal layer of the endometrium. Although many endometrial pathologies are thought to be associated with defects in these stem cells, studies on their identification and regulation are limited, primarily due to lack of easily accessible animal models, as these processes are unique to primates. Here we describe a robust new method to study endometrial regeneration and differentiation processes using human endometrial tissue slice cultures incorporating an air-liquid interface into a 3D matrix scaffold of type I collagen gel, allowing sustained tissue viability over three weeks. The 3D collagen gel-embedded endometrial tissue slices in a double-dish culture system responded to ovarian steroid hormones, mimicking the endometrial changes that occur in vivo during the menstrual cycle. These changes included the E2-induced upregulation of Ki-67, estrogen receptor (ER), and progesterone receptor (PR) in all endometrial compartments and were markedly suppressed by both P4 and E2 plus P4 treatments. There were also distinct changes in endometrial morphology after E2 and P4 treatments, including subnuclear vacuolation and luminal secretions in glands as well as decidualization of stromal cells, typical characteristics of a progestational endometrium in vivo. This long-term slice culture method provides a unique in vivo-like microenvironment for the study of human endometrial functions and remodeling during early pregnancy and experiments on stem cell populations involved in endometrial regeneration and remodeling. Furthermore, this model has the potential to enable studies on several endometrial diseases, including endometrial cancers and pregnancy complications associated with defects in endometrial remodeling.

The brain-placental axis: Therapeutic and pharmacological relevancy to pregnancy

The placenta plays a critical role in mammalian reproduction. Although it is a transient organ, its function is indispensable to communication between the mother and fetus, and supply of nutrients and oxygen to the growing fetus. During pregnancy, the placenta is vulnerable to various intrinsic and extrinsic conditions which can result in increased risk of fetal neurodevelopmental disorders as well as fetal death. The placenta controls the neuroendocrine secretion in the brain as a means of adaptive processes to safeguard the fetus from adverse programs, to optimize fetal development and other physiological changes necessary for reproductive success. Although a wealth of information is available on neuroendocrine functions in pregnancy, they are largely limited to the regulation of hypothalamus-pituitary-adrenal/gonad (HPA/ HPG) axis, particularly the oxytocin and prolactin system. There is a major gap in knowledge on systems-level functional interaction between the brain and placenta. In this review, we aim to outline the current state of knowledge about the brain-placental axis with description of the functional interactions between the placenta and the maternal and fetal brain. While describing the brain-placental interactions, a special emphasis has been given on the therapeutics and pharmacology of the placental receptors to neuroligands expressed in the brain during gestation. As a key feature of this review, we outline the prospects of integrated pharmacogenomics, single-cell sequencing and organ-on-chip systems to foster priority areas in this field of research. Finally, we remark on the application of precision genomics approaches to study the brain-placental axis in order to accelerate personalized medicine and therapeutics to treat placental and fetal brain disorders.

Bacterial Colonization of the Female Upper Genital Tract

Bacteria colonize most of the human body, and the female genital tract is not an exception. While the existence of a vaginal microbiota has been well established, the upper genital tract has been considered a sterile environment, with a general assumption that bacterial presence is associated with adverse clinical manifestation. However, recent metagenomic studies identified specific patterns of microbiota colonizing the uterus, fallopian tubes, ovaries, and placenta. These results need confirmation and further investigations since the data are only scarce. Bacterial colonization of these sites appears different from the vaginal one, despite evidence that vaginal bacteria could ascend to the upper genital tract through the cervix. Are these bacteria only commensal or do they play a role in the physiology of the female upper genital tract? Which are the genera that may have a negative and a positive impact on the female reproductive function? The aim of this review is to critically present all available data on upper genital tract microbiota and discuss its role in human reproduction, ranging from the technical aspects of these types of analyses to the description of specific bacterial genera. Although still very limited, research focusing on genital colonization of bacteria other than the vaginal milieu might bring novel insights into physiopathology of human reproduction.

Three-dimensional culture of endometrial cells from domestic cats: A new in vitro platform for assessing plastic toxicity

Plastic polymers can be combined with additives that modify physical properties and stability of the material. However, the biocompatibility of those additives is not well known. The objective of the study was to characterize the impact of zinc stearate-a common additive-through the development of a novel three-dimensional (3-D) in vitro platform with endometrial cells from domestic cats. Epithelial and stromal cells from adult uteri were isolated and cultured in medium supplemented with 3% Matrigel for two weeks in plastic tissue culture dishes that had been identified as polystyrene with and without zinc stearate by Raman, FTIR, and X-ray fluorescence spectroscopies. Three-dimensional cell structures that were obtained were measured and categorized by shape. Cell viability, proliferation, differentiation, organization, and apoptosis then were assessed by immuno-staining. Results indicated that zinc stearate did not affect 3-D endometrial cell structure morphology, viability, or cellular composition. This first study of a new in vitro platform will be useful for studies testing the influence of other additives, drugs, or exogenous hormones.