Progesterone Response Research Articles

Association of the PROGINS PgR polymorphism with susceptibility to female reproductive cancer: A meta-analysis of 30 studies.

The progesterone response of the nuclear progesterone receptor plays an important role in the female reproductive system. Changes in the function of the progesterone receptor gene may increase the risk of reproductive cancer. The present study performed a meta-analysis to examine whether the progesterone receptor gene PROGINS polymorphism was a susceptibility factor for female reproductive cancer. We searched the PubMed, Cochrane Library, Web of Science and EMBASE databases for literature on PROGINS polymorphisms and female reproductive cancer published before September 2020. We evaluated the risk using odds ratios [ORs] and 95% confidence intervals via fixed effects models and random-effects models, which were calculated for all five genetic models. We grouped the analyses by race, cancer, and HWE. Thirty studies comprised of 25405 controls and 19253 female reproductive cancer cases were included in this meta-analysis. We observed that the Alu insertion polymorphism and the V660L polymorphism were significantly associated with female reproductive cancer in the allele and dominant genetic models. The allele genetic model and (Alu-insertion polymorphism: OR = 1.22, 95% CI = 1.02-1.45; V660L polymorphism: OR = 1.02, 95% CI = 1.00-1.13) dominant genetic model (Alu-insertion polymorphism: OR = 1.27, 95% CI = 1.03-1.58; V660L polymorphism: OR = 1.10, 95% CI = 1.011.19) demonstrated a significantly increased risk of female reproductive cancer. A subgroup analysis according to ethnicity found that the Alu insertion was associated with female reproductive cancer incidence in white (Allele model: OR = 1.21, 95% CI = 1.00-1.45; Heterozygous model: OR = 3.44, 95% CI = 1.30-9.09) and Asian (Dominant model: OR = 3.12, 95% CI = 1.25-7.79) populations, but the association disappeared for African and mixed racial groups. However, the V660L polymorphism was significantly associated with female reproductive cancer in the African (Allele model: OR = 2.52, 95% CI = 1.14-5.56; Heterozygous model: OR = 2.83, 95% CI = 1.26-6.35) and mixed racial groups (Dominant model: OR = 1.28, 95% CI = 1.01-1.62). Subgroup analysis by cancer showed that the PROGINS polymorphism increased the risk of cancer in the allele model, dominant mode and heterozygous model, but the confidence interval for this result spanned 1 and was not statistically significant. This sensitivity was verified in studies with HWE greater than 0.5. Our meta-analysis showed that the progesterone receptor gene Alu insertion and the V660L polymorphism contained in the PROGINS polymorphism were susceptibility factors for female reproductive cancer.

Spatiotemporal expression pattern of Progesterone Receptor Component (PGRMC) 1 in endometrium from patients with or without endometriosis or adenomyosis

The endometrium plays a crucial role in reproduction and, in humans, is cyclically remodeled under hormonal control. Estradiol favors tissue proliferation whereas progesterone inhibits tissue growth and induces morphological changes. Endometriosis is often associated with fertility issues and with exacerbated estrogen and reduced progesterone concentration or response in the eutopic endometrium. However, underlying mechanisms remain unclear. Progesterone Receptor Membrane Component (PGRMC) 1 is a protein able to modulate progesterone response and its murine knockout reduced fertility. However, the precise spatiotemporal pattern of PGRMC1 expression in the human endometrium is still poorly characterized. We investigated variations of eutopic endometrial PGRMC1 expression by combining RT-qPCR, immunofluorescence and in situ hybridization. We found that PGRMC1 expression progressively increases during the proliferative phase and decreases during the secretory phase. However, immunolabeling and identification of mRNA-containing cells were regularly heterogeneous in samples, according to tissue depth, with a gradient extending from the surface epithelium towards the basalis. There was no significant difference in PGRMC1 mRNA amounts between patients with or without endometriosis or adenomyosis, for any phase of the menstrual cycle, but cells with strong or moderate PGRMC1 immunolabeling were reduced during the proliferative phase in endometriotic patients. In conclusion, although the cyclical variation of PGRMC1 expression globally follows fluctuation of ovarian steroids, further work is required to precisely characterize hormonal control and identify the additional levels of regulation responsible for local adjustment of PGRMC1 concentration. This is particularly important in the light of recent studies emphasizing the correlation between adequate PGRMC1 amounts and fertility.

FGF7/FGFR2-JunB signalling counteracts the effect of progesterone in luminal breast cancer.

We have recently demonstrated that fibroblast growth factor receptor 2 (FGFR2)‐mediated signalling alters progesterone receptor (PR) activity and response of oestrogen receptor α (ER)‐positive (ER+) breast cancer (BCa) cell lines to anti‐ER agents. Little is known about whether the crosstalk between ER and PR, shown to be modulated by the hormonal background, might also be affected by FGFR2. Here, PR‐dependent behaviour of ER+ BCa cells was studied in the presence of oestrogen (E2) and progesterone (P4) and/or FGF7. In vitro analyses showed that FGF7/FGFR2 signalling: (a) abolished the effect of P4 on E2‐promoted 3D cell growth and response to tamoxifen; (b) regulated ER and PR expression and activity; (c) increased formation of ER–PR complexes; and (d) reversed P4‐triggered deregulation of ER‐dependent genes. Analysis of clinical data demonstrated that the prognostic value of FGFR2 varied between patients with different menopausal status; that is, high expression of FGFR2 was significantly associated with longer progression‐free survival (PFS) in postmenopausal patients, whereas there was no significant association in premenopausal patients. FGFR2 was found to positively correlate with the expression of JunB proto‐oncogene, AP‐1 transcription factor subunit (JUNB), an ER‐dependent gene, only in premenopausal patients. Molecular analyses revealed that the presence of JunB was a prerequisite for FGFR2‐mediated abrogation of P4‐induced inhibition of cell growth. Our results demonstrate for the first time that the FGF7/FGFR2–JunB axis abolishes the modulatory effects of PR on ER‐associated biological functions in premenopausal ER+ BCa. This may provide foundations for a better selection of patients for FGFR‐targeting therapeutic strategies.

P-340 The endometrial switch following progesterone exposure correlates with uterine peristalsis

Abstract Study question What is the effect of the changes of the endometrium following progesterone exposure on uterine peristalsis? Summary answer Uteri with a greater increase endometrial thickness after progesterone exposure have significantly greater uterine peristalsis (UP). Therefore, endometrial compaction is associated with quieter uteri. What is known already Endometrial compaction is considered a sign of adequate response to progesterone. However, it is not always possible to visualize it. Little is known about endometrial switch following progesterone and its consequences after frozen embryo transfer, although it is hypothesized that increased endometrial growth after the window of implantation may be related to an increase in endogenous or exogenous oestrogen causing impairment of progesterone function. On the other hand, the role of progesterone in inhibiting endometrial contractile function is well known. Consequently, both the change in endometrial thickness and uterine contractility are indicators of progesterone function. Study design, size, duration This retrospective observational was carried out in Instituto Bernabeu of Alicante. The study included 215 patients with at least three previous implantation failures after egg donation treatment, which underwent uterine peristalsis assessment the day of embryo transfer from June 2017 to December 2021. Participants/materials, setting, methods UP assessment was performed using 4D ultrasound, recording a video for 6 minutes. UP variable was split in quartiles, and then the last quartile (UP ≥ 1,5 contractions per minute) was considered the hypercontractility group. All patients had performed an ultrasound to assess endometrial thickness between 7 to 10 days before embryo transfer. Endometrial compaction has been considered when it has decreased. Endometrial switch (ES) is considered the percentage between both endometrial measures. Main results and the role of chance The mean age of patients was 40,11 years who underwent an average of 3,75 embryo transfers. The average UP was 1,09 contractions per minute. The average ES was 9% of increased endometrium. Only 83 (38,6%) patients had endometrial compaction. To assess the association between UP and endometrial switch after progesterone exposure a univariate assessment was performed using Pearson’s correlation resulting in a negative correlation (r=-0,16; p = 0,019). It was used the hypercontractility group for performing bivariate logistic regression was performed to examine the effect of independent variables (previous miscarriages, previous pregnancies, C-section, endometriosis, adenomyosis, myomatosis and endometrial preparation) on ES. Greater ES is statistically associated to greater UP with OR 1,013 (95%IC: 1,002 to 1,025; p = 0,041). Limitations, reasons for caution It is a retrospective study based in patients with multiple implantation failure. It is possible that our conclusions couldn't be the same in patients with good prognosis. Wider implications of the findings Assessment of endometrial changes and uterine peristalsis provide information about the response of the uterus to progesterone exposure. However, more studies assessing it prospectively both would be interesting to define which population has high risk to develop situations with inadequate progesterone response. Trial registration number Not applicable

In Vivo Genome-Wide PGR Binding in Pregnant Human Myometrium Identifies Potential Regulators of Labor

The alterations in myometrial biology during labor are not well understood. The myometrium is the contractile portion of the uterus and contributes to labor, a process that may be regulated by the steroid hormone progesterone. Thus, human myometrial tissues from term pregnant in-active-labor (TIL) and term pregnant not-in-labor (TNIL) subjects were used for genome-wide analyses to elucidate potential future preventive or therapeutic targets involved in the regulation of labor. Using myometrial tissues directly subjected to RNA sequencing (RNA-seq), progesterone receptor (PGR) chromatin immunoprecipitation sequencing (ChIP-seq), and histone modification ChIP-seq, we profiled genome-wide changes associated with gene expression in myometrial smooth muscle tissue in vivo. In TIL myometrium, PGR predominantly occupied promoter regions, including the classical progesterone response element, whereas it bound mainly to intergenic regions in TNIL myometrial tissue. Differential binding analysis uncovered over 1700 differential PGR-bound sites between TIL and TNIL, with 1361 sites gained and 428 lost in labor. Functional analysis identified multiple pathways involved in cAMP-mediated signaling enriched in labor. A three-way integration of the data for ChIP-seq, RNA-seq, and active histone marks uncovered the following genes associated with PGR binding, transcriptional activation, and altered mRNA levels: ATP11A, CBX7, and TNS1. In vitro studies showed that ATP11A, CBX7, and TNS1 are progesterone responsive. We speculate that these genes may contribute to the contractile phenotype of the myometrium during various stages of labor. In conclusion, we provide novel labor-associated genome-wide events and PGR-target genes that can serve as targets for future mechanistic studies.

Progesterone and Inflammatory Response in the Oviduct during Physiological and Pathological Conditions.

Progesterone has been shown to be a potent suppressor of several inflammatory pathways. During pregnancy, progesterone levels increase, allowing for normal pregnancy establishment and maintenance. The dysregulation of progesterone, as well as inflammation, leads to poor pregnancy outcomes. However, it is unclear how progesterone imbalance could impact inflammatory responses in the oviduct and subsequently result in early pregnancy loss. Therefore, in this review, we describe the role of progesterone signaling in regulating the inflammatory response, with a focus on the oviduct and pathological conditions in the Fallopian tubes.

Genome wide expression analysis of circular RNAs in mammary epithelial cells of cattle revealed difference in milk synthesis.

Milk is an excellent source of nutrients for humans. Therefore, in order to enhance the quality and production of milk in cattle, it is interesting to examine the underlying mechanisms. A number of new investigations and research have found that, circRNA; a specific class of non-coding RNAs, is linked with the development of mammary gland and lactation. In the present study, genome wide identification and expression of the circRNAs in mammary epithelial cells of two distinct cattle breeds viz Jersey and Kashmiri at peak lactation was conducted. We reported 1554 and 1286 circRNA in Jersey and Kashmiri cattle, respectively, with 21 circRNAs being differentially expressed in the two breeds. The developmental genes of the established differentially expressed circRNAs were found to be largely enriched in antioxidant activity, progesterone, estradiol, lipid, growth hormone, and drug response. Certain pathways like MAPK, IP3K and immune response pathways were found significantly enriched in KEGG analysis. These results add to our understanding of the controlling mechanisms connected with the lactation process, as well as the function of circRNAs in bovine milk synthesis. Additionally, the comparative analysis of differentially expressed circRNAs showed significant conservation across different species.

A History of Neonatal Uterine Bleeding and Its Significance

Bleeding in newborns and young girls fascinated writers for more than a millennium. Initially, there was confusion between neonatal bleeding, early menstruation due to precocious puberty, and hemorrhage due to disease. During the 19th century descriptions appeared of what is referred to today as ‘neonatal menstruation’ or ‘neonatal uterine bleeding’. By the turn of the century, Halban linked bleeding to active substances present during pregnancy and hypothesized that, while the maternal uterus reacts with decidua formation, the “weaker” fetal uterus reacts only with menstrual-like changes. Despite this clear description, several alternative theories endured for decades. Bleeding was believed to be due to a ‘catarrhal’ or neoplastic state of the genital tract, pulmonary circulatory disorder, congenital heart malformations, closure of the umbilical cord or affections of the intestine. During the 1950s, progesterone response and resistance were proposed to explain the pathogenesis of bleeding and its low incidence. The fetal endometrium is resistant to the high circulating progesterone. A decidual response is infrequent and results in menstrual shedding upon progesterone withdrawal after birth. Further research linked fetal stress consequent to pregnancy complications and post-maturity to increased incidence and preterm birth to reduced incidence of neonatal uterine bleeding.

Prenatal androgenization causes expression changes of progesterone and androgen receptor mRNAs in the arcuate nucleus of female mice across development.

Prenatal exposure to excess androgens is associated with the development of polycystic ovary syndrome (PCOS). In prenatally androgenised (PNA) mice, a model of PCOS, progesterone receptor (PR) protein expression is reduced in arcuate nucleus (ARC) GABA neurons. This suggests a mechanism for PCOS-related impaired steroid hormone feedback and implicates androgen excess with respect to inducing transcriptional repression of the PR-encoding gene Pgr in the ARC. However, the androgen sensitivity of ARC neurons and the relative gene expression of PRs over development and following prenatal androgen exposure remain unknown. Here, we used a quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) of microdissected ARC to determine the relative androgen receptor (Ar) and progesterone receptor (Pgr) gene expression in PNA and control mice at five developmental timepoints. In a two-way analysis of variance, none of the genes examined showed expression changes with a statistically significant interaction between treatment and age, although PgrA showed a borderline interaction. For all genes, there was a statistically significant main effect of age on expression levels, reflecting a general increase in expression with increasing age, regardless of treatment. For PgrB and Ar, there was a statistically significant main effect of treatment, indicating a change in expression following PNA (increased for PgrB and decreased for Ar), regardless of age. For PgrA, there was a borderline main effect of treatment, suggesting a possible change in expression following PNA, regardless of age. PgrAB gene expression changes showed no significant main effect of treatment. We additionally examined androgen and progesterone responsiveness specifically in P60 ARC GABA neurons using RNAScope® (Advanced Cell Diagnostics, Inc.) in situ hybridization. This analysis revealed that Pgr and Ar were expressed in the majority of ARC GABA neurons in normal adult females. However, our RNAScope® analysis did not show significant changes in Pgr or Ar expression within ARC GABA neurons following PNA. Lastly, because GABA drive to gonadotropin-releasing hormone neurons is increased in PNA, we hypothesised that PNA mice would show increased expression of glutamic acid decarboxylase (GAD), the rate-limiting enzyme in GABA production. However, the RT-qPCR showed that the expression of GAD encoding genes (Gad1 and Gad2) was unchanged in adult PNA mice compared to controls. Our findings indicate that PNA treatment can impact Pgr and Ar mRNA expression in adulthood. This may reflect altered circulating steroid hormones in PNA mice or PNA-induced epigenetic changes in the regulation of Pgr and Ar gene expression in ARC neurons.

AG-205 Upregulates Enzymes Involved in Cholesterol Biosynthesis and Steroidogenesis in Human Endometrial Cells Independently of PGRMC1 and Related MAPR Proteins.

An inappropriate response to progestogens in the human endometrium can result in fertility issues and jeopardize progestin-based treatments against pathologies such as endometriosis. PGRMC1 can mediate progesterone response in the breast and ovaries but its endometrial functions remain unknown. AG-205 is an alleged PGRMC1 inhibitor but its specificity was recently questioned. We added AG-205 in the cultures of two endometrial cell lines and performed a transcriptomic comparison. AG-205 significantly increased expression of genes coding enzymes of the cholesterol biosynthetic pathway or of steroidogenesis. However, these observations were not reproduced with cells transfected with siRNA against PGRMC1 or its related proteins (MAPRs). Furthermore, AG-205 retained its ability to increase expression of selected target genes even when expression of PGRMC1 or all MAPRs was concomitantly downregulated, indicating that neither PGRMC1 nor any MAPR is required to mediate AG-205 effect. In conclusion, although AG-205 has attractive effects encouraging its use to develop therapeutic strategies, for instance against breast cancer, our study delivers two important warning messages. First, AG-205 is not specific for PGRMC1 or other MAPRs and its mechanisms of action remain unclear. Second, due to its effects on genes involved in steroidogenesis, its use may increase the risk for endometrial pathologies resulting from imbalanced hormones concentrations.

SINGLE CELL ANALYSIS REVEALS HETEROGENEITY IN THE DISEASE RELEVANT CELL TYPES OF ADENOMYOSIS

To identify cellular composition and gene expression profiles of the cell types in adenomyotic tissue, eutopic endometrium, and normal myometrium of the women with diffuse adenomyosis. Adenomyotic tissue (n=3), eutopic endometrium (n=3), and myometrium (n=3) were obtained from premenopausal women who underwent hysterectomy for diffuse adenomyosis and confirmed by frozen section histologic evaluation. Following digestion, the stromal and smooth muscle cells were collected, and the epithelial cell pellets were further digested. After checking the viability, which was at least 75%, samples subjected the 10x Genomics® Single Cell Protocol. Processed data from the Cell Ranger pipeline was analyzed using the R package Seurat (v3.2). Uniform Manifold Approximation and Projection was generated to visualize cell clusters. The Wilcoxon rank sum test was used to compare the gene expression profile for each cluster which were annotated by marker genes. We identified ciliated and unciliated epithelial cells, fibroblast-like cells, smooth muscle cells (SMC), endothelial cells, pericytes, vascular SMCs, progenitor cells, T cells, NK cells, B cells, MQ, and monocytes, neurons and myeloid progenitors in the adenomyotic uterus. Notably, comparative transcriptome analysis of epithelial cells in eutopic endometrium and adenomyotic tissue revealed a small subset of differentially expressed genes, indicating the stability of the transcriptional program of these cells. On the other hand, we identified a high degree of heterogeneity among the fibroblast populations. Intriguingly, fibroblast-like cells in adenomyotic vs eutopic endometrial tissue showed higher expression of progesterone-responsive genes. In contrast, eutopic endometrial epithelial cells displayed higher expression of progesterone-responsive genes. Pseudo-time analysis in eutopic endometrium have demonstrated evidence of both epithelial-mesenchymal and mesenchymal-epithelial transition originating from a progenitor cell population and pericytes, respectively. Our analyses revealed 15 distinct cell populations in adenomyotic tissue. Fibroblast-like cells constituted the majority of all cell types which showed a high degree of heterogeneity, which may be due to different transcriptional states linked to the intense inflammatory processes in adenomyosis. Our results suggest that progesterone response may vary between cell types in adenomyotic tissue. The lack of a substantial difference between epithelial cells in adenomyosis and adjacent endometrium supports the postulated mechanism whereby invagination of eutopic endometrial tissue is responsible for adenomyosis.

Secoiridoids from Dogwood (Cornus officinalis) Potentiate Progesterone Signaling.

The use of botanical dietary supplements for the alleviation of conditions such as hot flashes, premenstrual syndrome, and fertility is prolific worldwide. Estrogen and progesterone receptors (ER and PR) and their corresponding steroid hormones are critical for the relief of hot flashes and the treatment of patients who develop endometriosis, and these pathways can influence the development of endometrial, ovarian, and breast cancers. However, few studies have investigated or identified the natural product components in herbal supplements that act on the PR. In the current study, a new secoiridoid, demethoxy-cornuside (1), along with six known secoiridoids (2-7) were isolated from the twigs of dogwood (Cornus officinalis) by bioassay-guided isolation with a progesterone response element (PRE)/luciferase (Luc) reporter assay in Ishikawa cells. Four phytoprogestins (1, 2, 6, 7) potentiated the effect of progesterone in the PRE/Luc assay. This study demonstrates that C. officinalis components might potentiate progesterone signaling in the presence of progesterone, which could modify progesterone receptor action in hormone-responsive tissues such as the uterus and mammary gland.

Mechanism of Action of Irilone as a Potentiator of Progesterone Receptor Signaling

Progesterone signaling and its proper regulation is important for reproductive function. When progesterone signaling is dysregulated, gynecological diseases can occur, for example endometriosis, uterine fibroids, and endometrial cancer. While these diseases are treated with progestin therapy, progestins can bind to multiple steroid receptors, exerting side effects of weight gain, immunosuppression, cardiovascular disease, and stroke. Discovering an alternative progestin that is selective for the progesterone receptor (PR) is ideal. One potential source of such an alternative is botanical dietary supplements, which have become increasingly popular among consumers with sales reaching $9.6 billion in 2019. Although botanical supplements are popular, the chemical structures and biological action of botanical supplements would benefit from deeper scientific investigation. Studies of Trifolium pratense L. (red clover), primarily used for the treatment of menopausal symptoms, identified phytoestrogen compounds as the chemicals that mitigate those symptoms. Interestingly, irilone, identified from red clover, potentiated progesterone signaling via a progesterone response element luciferase (PRE/Luc) assay. Potentiation is when a compound has no activity by itself but when combined with another molecule, i.e. progesterone, that compound enhances PR activity. Prior to irilone, a natural compound with the ability to potentiate progesterone signaling had not been previously reported. The purpose of this study was to determine the mechanism of action of irilone. We hypothesized that irilone was potentiating PR by blocking PR degradation and by altering PR post-translational modifications. Irilone was found to potentiate 5 nM P4 using a PRE-luciferase assay in both T47D and Ishikawa PR expressing cells. Since PR is a downstream target gene of ER, we investigated if irilone also had ER activity. Irilone increased expression of an ERE-luciferase reporter gene. Next, we investigated if irilone could stabilize PR degradation and if irilone altered PR phosphorylation via western blot. Irilone was found to increase PR protein levels, but when ER was blocked, this was mitigated. In the presence of P4, irilone did not increase phosphorylation of serine 294 on PR. Future studies will determine if irilone is altering sumoylation of PR, and if irilone can potentiate PR signaling in vivo. Determining how irilone is potentiating progesterone will help us understand PR biology and could be an effective treatment for gynecological diseases by enhancing endogenous progesterone action.

Illuminating the "Black Box" of Progesterone-Dependent Embryo Implantation Using Engineered Mice.

Synchrony between progesterone-driven endometrial receptivity and the arrival of a euploid blastocyst is essential for embryo implantation, a prerequisite event in the establishment of a successful pregnancy. Advancement of embryo implantation within the uterus also requires stromal fibroblasts of the endometrium to transform into epithelioid decidual cells, a progesterone-dependent cellular transformation process termed decidualization. Although progesterone is indispensable for these cellular processes, the molecular underpinnings are not fully understood. Because human studies are restricted, much of our fundamental understanding of progesterone signaling in endometrial periimplantation biology comes from in vitro and in vivo experimental systems. In this review, we focus on the tremendous progress attained with the use of engineered mouse models together with high throughput genome-scale analysis in disclosing key signals, pathways and networks that are required for normal endometrial responses to progesterone during the periimplantation period. Many molecular mediators and modifiers of the progesterone response are implicated in cross talk signaling between epithelial and stromal cells of the endometrium, an intercellular communication system that is critical for the ordered spatiotemporal control of embryo invasion within the maternal compartment. Accordingly, derailment of these signaling systems is causally linked with infertility, early embryo miscarriage and gestational complications that symptomatically manifest later in pregnancy. Such aberrant progesterone molecular responses also contribute to endometrial pathologies such as endometriosis, endometrial hyperplasia and cancer. Therefore, our review makes the case that further identification and functional analysis of key molecular mediators and modifiers of the endometrial response to progesterone will not only provide much-needed molecular insight into the early endometrial cellular changes that promote pregnancy establishment but lend credible hope for the development of more effective mechanism-based molecular diagnostics and precision therapies in the clinical management of female infertility, subfertility and a subset of gynecological morbidities.

Disturbed progesterone signalling in an advanced preclinical model of endometriosis

Research questionDo human endometriosis organoids recapitulate aberrant progesterone signalling in the disease to serve as advanced experimental models for uncovering epigenetic mechanisms involved in attenuated progesterone response in endometriosis? DesignInitially, the organoids were established from acquired biopsies (women with and without endometriosis) and characterized by morphological, histological and immunostaining analyses. Results: A panel of endometriosis-related genes showed a pattern of expressions in cytochrome c oxidase subunit II (COX2), matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor of metalloproteinase-3 (TIMP3), transforming growth factor beta 1 (TGF-β1), and zinc finger E-box binding homeobox 1 (ZEB1), and a contradictory expression pattern for cadherin (CDH1), POU class 5 homeobox 1 (POU5F1; also known as OCT4), and Nanog homeobox (NANOG) in the endometriosis organoids that is concordant with published research. These endometriosis organoids failed to upregulate 17β-Hydroxysteroid dehydrogenase 2 (17HSDβ2), progestogen associated endometrial protein (PAEP), secreted phosphoprotein 1 (SPP1), and leukaemia inhibitory factor (LIF) in response to progesterone at the level observed in control endometrium organoids. Progesterone receptor B (PRB) gene expression significantly decreased in both eutopic and ectopic organoids compared with control endometrium organoids. DNA hypermethylation, as an epigenetic mechanism for suppression of transcription, was detected at the PRB promoter in the eutopic, but not ectopic, organoids. Therefore, other epigenetic mechanisms, such as histone modifications and microRNAs, may be responsible for PRB downregulation in ectopic organoids. ConclusionsEndometriosis organoids are powerful preclinical models that can be used to investigate the molecular mechanisms involved in endometriosis-associated progesterone resistance.

Identification of Host Factors Associated with the Development of Equine Herpesvirus Myeloencephalopathy by Transcriptomic Analysis of Peripheral Blood Mononuclear Cells from Horses.

Equine herpesvirus-1 is the cause of respiratory disease, abortion, and equine herpesvirus myeloencephalopathy (EHM) in horses worldwide. EHM affects as many as 14% of infected horses and a cell-associated viremia is thought to be central for EHM pathogenesis. While EHM is infrequent in younger horses, up to 70% of aged horses develop EHM. The aging immune system likely contributes to EHM pathogenesis; however, little is known about the host factors associated with clinical EHM. Here, we used the “old mare model” to induce EHM following EHV-1 infection. Peripheral blood mononuclear cells (PBMCs) of horses prior to infection and during viremia were collected and RNA sequencing with differential gene expression was used to compare the transcriptome of horses that did (EHM group) and did not (non-EHM group) develop clinical EHM. Interestingly, horses exhibiting EHM did not show respiratory disease, while non-EHM horses showed significant respiratory disease starting on day 2 post infection. Multiple immune pathways differed in EHM horses in response to EHV-1. These included an upregulation of IL-6 gene expression, a dysregulation of T-cell activation through AP-1 and responses skewed towards a T-helper 2 phenotype. Further, a dysregulation of coagulation and an upregulation of elements in the progesterone response were observed in EHM horses.

Role of Constitutive STAR in Leydig Cells.

Leydig cells contain significant amounts of constitutively produced steroidogenic acute regulatory protein (STAR; STARD1). Hormone-induced STAR plays an essential role in inducing the transfer of cholesterol into the mitochondria for hormone-dependent steroidogenesis. STAR acts at the outer mitochondrial membrane, where it interacts with a protein complex, which includes the translocator protein (TSPO). Mutations in STAR cause lipoid congenital adrenal hyperplasia (lipoid CAH), a disorder characterized by severe defects in adrenal and gonadal steroid production; in Leydig cells, the defects are seen mainly after the onset of hormone-dependent androgen formation. The function of constitutive STAR in Leydig cells is unknown. We generated STAR knockout (KO) MA-10 mouse tumor Leydig cells and showed that STAR KO cells failed to form progesterone in response to dibutyryl-cAMP and to TSPO drug ligands, but not to 22(R)-hydroxycholesterol, which is a membrane-permeable intermediate of the CYP11A1 reaction. Electron microscopy of STAR KO cells revealed that the number and size of lipid droplets were similar to those in wild-type (WT) MA-10 cells. However, the density of lipid droplets in STAR KO cells was drastically different than that seen in WT cells. We isolated the lipid droplets and analyzed their content by liquid chromatography–mass spectrometry. There was a significant increase in cholesteryl ester and phosphatidylcholine content in STAR KO cell lipid droplets, but the most abundant increase was in the amount of diacylglycerol (DAG); DAG 38:1 was the predominantly affected species. Lastly, we identified genes involved in DAG signaling and lipid metabolism which were differentially expressed between WT MA-10 and STAR KO cells. These results suggest that constitutive STAR in Leydig cells is involved in DAG accumulation in lipid droplets, in addition to cholesterol transport. The former event may affect cell functions mediated by DAG signaling.

Abstract PO030: Understanding the influence of adiposity on the endometrium using human primary endometrial organoids

Abstract Endometrial cancer is the most commonly diagnosed type of gynecological cancer, and obesity is a major risk factor for this disease. Despite rising rates of obesity and endometrial cancer, it is still unclear how obesity alters the benign endometrium and the endometrial hormonal response to promote carcinogenesis. We used an endometrial organoid model to investigate how adiposity predisposes women to develop endometrial cancer. We hypothesized that increased adiposity would directly alter endometrial gene expression and diminish the protective progesterone response of the benign endometrium. Scaffold-free, three-dimensional endometrial organoids consisting of both epithelial and stromal cells from benign endometrial tissue were generated. Organoids were cocultured with different numbers of adipocyte spheroids to represent different levels of adiposity and were treated with a menstrual cycle level of hormones (E2 + P4 +T) over 14 days. Endometrial organoid gene expression was investigated using RNA-seq. Coculturing endometrial organoids with 30 adipocyte spheroids in the presence of E2, P4, and T caused significant differential expression of pathways involved in metabolism, angiogenesis, chromatin modification, and metal ion response, compared to endometrial organoids cultured without adipocyte spheroids. We investigated the metal ion response pathways that were altered and found that many of the most significantly differentially regulated genes in the metal ion response pathways belonged to the metallothionein (MT) family of genes. The expression of MT1A, MT1M, MT1X, and MT2A decreased approximately 50% in endometrial organoids cocultured with 30 adipocyte spheroids. Furthermore, although the results were not statistically significant, we observed a downregulation of the progesterone-responsive genes HSD17B2, IGFBP1, PAEP, PRL, FOXO1, and SPP1 in the endometrial organoids cultured with 30 adipocyte spheroids. Our results show that culturing endometrial organoids in conditions of increased adiposity alters endometrial gene expression and may change the way the endometrium responds to progesterone. Metallothioneins, which are downregulated in the presence of adipocyte spheroids, are important modulators of zinc and copper ions and reactive oxygen species in the cell. Progesterone plays an important protective role against endometrial cancer. In summary, our data show that adipocytes may influence the progesterone response of the benign endometrium. Further investigation into the role of progesterone-driven metallothioneins in the endometrium is currently underway. Citation Format: Alina R. Murphy, J. Julie Kim. Understanding the influence of adiposity on the endometrium using human primary endometrial organoids [abstract]. In: Proceedings of the AACR Virtual Special Conference: Endometrial Cancer: New Biology Driving Research and Treatment; 2020 Nov 9-10. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(3_Suppl):Abstract nr PO030.

Mixed-lineage leukaemia 1 contributes to endometrial stromal cells progesterone responsiveness during decidualization.

Studies have reported that non‐receptive endometrium or abnormal decidualization was closely related to recurrent implantation failure (RIF). MLL1 is a histone H3 lysine 4 trimethylation (H3K4me3) transferase that regulates the transcriptional activation of target genes. The role of MLL1 has been underexplored during decidualization. In our research, we found the expression of MLL1 was closely related to endometrial receptivity, and it was responsible to hormone stimulation. Inhibiting the function of MLL1 by MM102 reduced the transformation of HESCs. Furthermore, down‐regulation of MLL1 by siRNA transfection significantly decreased PGR and its target genes expression. MLL1 act as a co‐activator of ERα, and both of them were recruited to PGR regulatory regions, thus promote PGR transcription. Our study showed that MLL1 plays a key role in promoting progesterone signalling transmission.

Analyses of progesterone responsiveness change and latent inflammation associated with cervical ripening using a human cervical fibroblasts culture system

Analyses of progesterone responsiveness change and latent inflammation associated with cervical ripening using a human cervical fibroblasts culture system