HOXA10 signals on the highway through pregnancy

Effect of endometrial biopsy method on ribonucleic acid quality and gene expression analysis in patients with leiomyoma

Objective

To compare ribonucleic acid (RNA) quantity and purity in tissue collected with different endometrial sampling methods to establish the optimal tool for use in endometrial gene expression studies.

Design

Observational study.

Setting

University hospital.

Patients

Fourteen patients with submucosal leiomyomas.

Interventions

Unguided biopsies were obtained using a low-pressure suction device before hysteroscopy from 14 patients with submucosal leiomyomas followed by guided biopsy with a resectoscope loop. Fifty-seven samples were collected: 25 obtained using a suction device and 32 with a loop.

Main Outcome Measures

Total biopsy weight, RNA purity, and RNA yield for each collection method. After complementary deoxyribonucleic acid synthesis, HOXA10 expression was measured by quantitative polymerase chain reaction in the endometrium overlying and remote from the leiomyoma, as similar expression throughout the cavity was a prerequisite for the use of unguided biopsy method.

Results

The median weight of the samples was significantly larger when obtained with the low-pressure suction device than with the resectoscope loop (153 vs. 20 mg). The RNA yield was similar (suction curette, 1,625 ng/mg; resectoscope loop, 1,779 ng/mg). The A260-to-A280 ratio was satisfactory for 94.7 % of the samples, with no difference between the groups. The endometrial expression of HOXA10 was similar in areas overlying the leiomyoma compared with that in remote endometrial sites (2-ΔCt = 0.0224 vs. 0.0225).

Conclusions

Low-pressure endometrial suction devices provide tissue samples with acceptable RNA purity and quantity for gene expression studies. The expression of HOXA10 did not differ between endometrial sampling sites even in the presence of leiomyomas.

hUMSCs Restore Uterine Function by Inhibiting Endometrial Fibrosis via Regulation of the MMP-9/TIMP-1 Ratio in CDDP-Induced Injury Rats

The fertility of females of childbearing age who are cured of cancer by chemotherapy is gradually declining globally. As a broad-spectrum chemotherapy drug in clinic, the damage of cisplatin (CDDP) to female reproductive function cannot be ignored. At present, the study of CDDP damage to the uterus is not sufficient, and the exact mechanism needs to be further explored. Therefore, we conducted this research to determine whether uterine injury in CDDP-induced injury rats might be improved by human umbilical cord mesenchymal stem cells (hUMSCs) and to further explore the precise mechanism. The rat model of CDDP-induced injury was established by intraperitoneal injection of CDDP, and hUMSCs were injected into the tail vein 7 days later. In vivo, uterine function in CDDP-induced injury rats was affected after hUMSC transplantation. In vitro, the specific mechanism was further explored from the cell and protein levels. Overall, the specific reason of CDDP-induced uterine dysfunction in rats was endometrial fibrosis, which was significantly improved after hUMSC transplantation. Further investigation of the mechanism found that hUMSCs could regulate the ratio of matrix metalloproteinase-9 (MMP-9)/tissue inhibitor of metalloproteinase-1 (TIMP-1) in endometrial stromal cells (EnSCs) after CDDP injury.

FHL1 mediates HOXA10 deacetylation via SIRT2 to enhance blastocyst-epithelial adhesion

Recurrent implantation failure (RIF) is a rather thorny problem in the clinical practice of assisted reproductive technology. Due to the complex aetiology of RIF, its pathogenesis is far from fully understood, and there is no effective treatment available. Here, We explored the regulatory mechanism of the four half-domains of LIM domain 1 (FHL1), which is significantly downregulated in the endometrium of RIF patients, in blastocyst-epithelial adhesion. Indeed, FHL1 expression was dramatically increased in normal female mid-secretory endometrial epithelial cells and was abnormally reduced in RIF patients. Furthermore, FHL1 overexpression promoted blastocyst-epithelial adhesion, and interfering with FHL1 expression in the mouse uterus significantly inhibited embryo implantation. Mechanistically, FHL1 did not regulate HOXA10 mRNA expression but increased HOXA10 protein stability and activated HOXA10, thereby promoting its regulation of downstream gene expression and the β3 integrin/FAK pathway. Meanwhile, FHL1 regulates HOXA10 function by increasing HOXA10 deacetylation through enhanced binding of HOXA10 and SIRT2. SIRT2-specific inhibitors can significantly inhibit this effect. In the endometrial epithelial cells of RIF patients, the correlation between FHL1 and HOXA10 and its downstream target genes has also been verified. Finally, our data indicated FHL1 is a regulatory molecule that promotes blastocyst-epithelial adhesion. Altogether, downstream dysfunction due to aberrant FHL1 expression is an important molecular basis for embryo implantation failure in patients with RIF and to provide new potential therapeutic targets.

The Estrogen Receptor α Cistrome in Human Endometrium and Epithelial Organoids

Endometrial health is affected by molecular processes that underlie estrogen responses. We assessed estrogen regulation of endometrial function by integrating the estrogen receptor α (ESR1) cistromes and transcriptomes of endometrial biopsies taken from the proliferative and mid-secretory phases of the menstrual cycle together with hormonally stimulated endometrial epithelial organoids. The cycle stage-specific ESR1 binding sites were determined by chromatin immunoprecipitation and next-generation sequencing and then integrated with changes in gene expression from RNA sequencing data to infer candidate ESR1 targets in normal endometrium. Genes with ESR1 binding in whole endometrium were enriched for chromatin modification and regulation of cell proliferation. The distribution of ESR1 binding sites in organoids was more distal from gene promoters when compared to primary endometrium and was more similar to the proliferative than the mid-secretory phase ESR1 cistrome. Inferred organoid estrogen/ESR1 candidate target genes affected formation of cellular protrusions and chromatin modification. Comparison of signaling effected by candidate ESR1 target genes in endometrium vs organoids reveals enrichment of both overlapping and distinct responses. Our analysis of the ESR1 cistromes and transcriptomes from endometrium and organoids provides important resources for understanding how estrogen affects endometrial health and function.

Circadian desynchronization in pregnancy of Golden hamster following long time light exposure: Involvement of Akt/FoxO1 pathway

Coordination between central and peripheral reproductive clocks in females is poorly understood. Long light is having a hazardous effect on reproductive health. Hence, explored the effect of long-time light exposure (LLD; 16L:8D) on the central and peripheral reproductive (ovary and uterus) clock genes (Bmal1, Clock, Per1, Per2, Cry1 and Cry2) and its downstream regulators (Aanat, Egf, Cx26, Cx43, ERα, pAktS-473, pAktT-308, pFoxO1T-24, 14-3-3, HoxA10, HoxA11 and Pibf) expression in non-pregnant and pregnant Golden hamster. Young adult Golden hamsters were exposed to LLD for 30 days and then were mated. We observed that LLD exposure increased the thickness of the endometrium and reduced myometrium thickness, resembling uterine adenomyosis. In non-pregnant females LLD altered the expressions of clock genes in suprachiasmatic nuclei (SCN), ovary and the uterus along with serum estradiol rhythm. LLD upregulated Egf and downregulated Aanat, Cx26, and Cx43 mRNA levels in uterus. LLD upregulated Akt/FoxO1 phosphorylation and 14-3-3 expressions in the uterus of nonpregnant females. LLD exposure to pregnant females lowered serum progesterone, Aanat, Pibf, Hoxa10, and Hoxa11 mRNA expressions on D4 (peri-implantation) and D8 (post-implantation) resulting in a low implantation rate on D8 (post-implantation). Hence it is evident that the frequent pregnancy anomalies noted under a long light schedule might be due to desynchronization in Aanat, Pibf, Hoxa10, and Hoxa11 as well as the central and peripheral clock genes (Bmal1, Clock, Per1, Per2, Cry1 and Cry2). LLD exposure desynchronized the central and peripheral reproductive clock affecting uterine physiology via Akt/FoxO1 pathway in Golden hamsters. Thus, LLD is a risk factor for female reproductive health and fertility.

The roles and expression of HOXA/Hoxa10 gene: A prospective marker of mammalian female fertility?

This review addresses the influence of homebox A10/a10 (HOXA/Hoxa10) gene on reproductive tract anatomy and functional fertility in mammalian species, and discusses major endocrine and environmental regulators of HOXA/Hoxa10 expression. Female reproductive efficiency or success is a function of several factors including the ovulation and fertilization rate, and uterine receptivity. A family of HOX/Hox genes establishes the segmental identity of the reproductive tract during embryogenesis and retains its physiological plasticity in sexually mature animals and humans. In particular, the HOXA/Hoxa10 gene is an intrinsic component of implantation, decidualization, and immunomodulation in the adult uterus. It was, therefore, suggested that knowledge of HOXA/Hoxa10 regulation might be essential in navigating molecular mechanisms with the aim of enhancing female reproductive potential. However, a recent study in pigs revealed a lack of associations between endometrial HOXA10 expression and reproductive tract morphology, and very poor correlations with sows' fertility metrics. Retinoic acid mainly regulates 3' HOX/Hox paralogs but may also modify the expression of downstream HOX/Hox genes, including HOXA/Hoxa10. Sex steroids directly regulate HOXA/Hoxa10 expression. The vitamin D receptor pathway modulates HOXA/Hoxa10 expression in the adult reproductive tract. Lastly, endocrine disruptors such as diethylstilbestrol, methoxychlor, bisphenol A, and isoflavones were shown to alter HOXA/Hoxa10 expression, thus affecting reproductive competence of the female.

Paired-like homeodomain transcription factor 2 affects endometrial cell function and embryo implantation through the Wnt/β-catenin pathway

The successful implantation of embryos is crucial for pregnancy in mammals. This complex process is inevitably dependent on the development of the endometrium. The paired-like homeodomain transcription factor 2 (PITX2) is involved in a variety of biological processes, but whether it is involved in embryo implantation has not been reported. In this study, we aimed to investigate uterine expression and regulation of PITX2 during implantation. We found that PITX2 was elevated in the human endometrium in the secretory phase. The results of the pregnant mouse models showed that PITX2 expression was spatiotemporal in mouse endometrial tissue throughout peri-implantation period, and it was significantly upregulated at the time of implantation. Interestingly, PITX2 was mainly localized to the glandular epithelium cells on D2.5-3.5 of pregnancy, while D5.5-6.5 was largely expressed in stromal cells. In vitro, PITX2 regulated endometrial cells proliferation, migration, invasion, and other functions through the Wnt/β-catenin signaling pathway. In addition, a significant decrease in the rate of embryo implantation was observed after injecting PITX2 small interfering RNA into the uterine horn. These results demonstrate the effects of PITX2 on the physiological function of endometrial cells and embryo implantation, suggesting a role in the endometrial regulatory mechanism during implantation.

Glyphosate Herbicide: Reproductive Outcomes and Multigenerational Effects

Glyphosate base herbicides (GBHs) are the most widely applied pesticides in the world and are mainly used in association with GBH-tolerant crop varieties. Indiscriminate and negligent use of GBHs has promoted the emergence of glyphosate resistant weeds, and consequently the rise in the use of these herbicides. Glyphosate, the active ingredient of all GBHs, is combined with other chemicals known as co-formulants that enhance the herbicide action. Nowadays, the safety of glyphosate and its formulations remain to be a controversial issue, as evidence is not conclusive whether the adverse effects are caused by GBH or glyphosate, and little is known about the contribution of co-formulants to the toxicity of herbicides. Currently, alarmingly increased levels of glyphosate have been detected in different environmental matrixes and in foodstuff, becoming an issue of social concern. Some in vitro and in vivo studies have shown that glyphosate and its formulations exhibit estrogen-like properties, and growing evidence has indicated they may disrupt normal endocrine function, with adverse consequences for reproductive health. Moreover, multigenerational effects have been reported and epigenetic mechanisms have been proved to be involved in the alterations induced by the herbicide. In this review, we provide an overview of: i) the routes and levels of human exposure to GBHs, ii) the potential estrogenic effects of glyphosate and GBHs in cell culture and animal models, iii) their long-term effects on female fertility and mechanisms of action, and iv) the consequences on health of successive generations.

O-GlcNAc modification mediates aquaporin 3 to coordinate endometrial cell glycolysis and affects embryo implantation

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O-GlcNAcylation affects endometrial cell physiological changes and implantation

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O-GlcNAcylation causes glucose metabolism to be redirected to PPP and HBP

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O-GlcNAcylation-mediated AQP3 provides compensation for glycolysis

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O-GlcNAcylation of Sp1 promotes the expression of AQP3

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OO-GlcNAcylation of Sp1 affects its stability

Introduction

Objectives

Methods

Results

Conclusion

Electroacupuncture Improves Pregnancy Outcomes in Rats with Thin Endometrium by Promoting the Expression of Pinopode-Related Molecules

A thin endometrium affects the success of assisted reproduction due to low endometrial receptivity. Acupuncture improves endometrial receptivity and promotes the formation of pinopodes, the ultrastructure marker implantation window. However, the specific underlying mechanisms remain unclear. In this study, the efficacy of acupuncture treatment and its underlying mechanism were investigated by analyzing pregnancy rate, pinopode formation, and related molecular markers in thin endometrium model rats. Absolute ethanol (95%) was injected into the uteruses of female Sprague-Dawley rats to construct a thin endometrium model. In this model, acupuncture stimulation at EX-CA1, SP6, and CV4 ameliorated the pregnancy rate. Significantly increased embryo implantation, endometrial thickness, numbers of glands, and blood vessels were observed in the electroacupuncture (EA) group compared to the model group. The number of pinopodes in the EA group was abundant, with a shape similar to that of the control group. Additionally, significantly higher expression levels of pinopode-related markers, including integrin αvβ3, homeobox A10 (HOXA10), heparin-binding EGF-like growth factor (HBEGF), estrogen receptor alpha (ERα), and progesterone receptor (PR), were observed in the EA group than those in the model group. In conclusion, EA had a positive effect on the endometrial receptivity of thin endometrium model rats by improving pinopode formation through multiple molecular targets.

Identification of HOXA10 target genes in human endometrial stromal cells by RNA-seq analysis

Homeobox A10 (HOXA10) is a transcription factor belonging to the homeobox gene family. It is highly expressed in endometrial stromal cells (ESCs) and plays essential roles in the proliferation and differentiation of endometrium, the establishment of endometrial receptivity and embryo implantation. However, little is known about the target genes and signaling pathways regulated by HOXA10 in ESCs. In this study, we identified 1830 transcripts regulated by HOXA10 in ESCs by RNA interference (RNAi) and RNA-sequencing (RNA-seq) analysis, of which 980 were positively regulated by HOXA10 and 850 were negatively regulated by HOXA10. Interestingly, matrix metallopeptidase-11 was downregulated by HOXA10 in stromal cells verified by quantitative real-time polymerase chain reaction and western blot analysis. Pathway analysis demonstrated that the target genes were enriched in various pathways, including cellular metabolism, DNA replication and repair, cell junction, and lysosome and signal transduction. The results of the present study provide novel insights into the mechanism underlying HOXA10 regulation in ESCs and may identify novel targets for the diagnosis and treatment of endometrium-related infertility.

Extracellular vesicles in embryo implantation and disorders of the endometrium

Implantation of the embryo is a rate-limiting step for a successful pregnancy, and it requires an intricate crosstalk between the embryo and the endometrium. Extracellular vesicles (EVs) are membrane-enclosed, nano-sized structures produced by cells to mediate cell to cell communication and modulate a diverse set of biological processes. Herein, we review the involvement of EVs in the process of embryo implantation and endometrial diseases. EVs have been isolated from uterine fluid, cultured endometrial epithelial/stromal cells and trophectodermal cells. The endometrial epithelial and stromal/decidual cell-derived EVs and its cargo are internalized bythe trophoblast cells, and they regulate a diverse set of genes involved in adhesion, invasion and migration. Conversely, the embryo-derived EVs and its cargo are internalized by epithelial and immune cells of the endometrium for biosensing and immunomodulation required for successful implantation. EVs have also been shown to play a role in infertility, recurrent implantation failure, endometriosis, endometritis and endometrial cancer. Further research should set a stage for EVs as non-invasive "liquid biopsy" tools for assessment of endometrial health.

Progesterone Regulates Glucose Metabolism Through Glucose Transporter 1 to Promote Endometrial Receptivity

Successful embryo implantation requires receptive endometrium, which is conducive to the process of embryo recognition, adhesion, and invasion within a certain period of time and is inseparable from the dynamic interaction between 17β-estradiol (E2) and progesterone (P4). Proper glucose metabolism is critical for the profound physiological changes in the endometrium entering the receptive state. And glucose transporters (GLUTs) are responsible for intracellular uptake of glucose and are the first step in glucose metabolism. Prior literature has reported the presence of GLUTs in the endometrium. However, we still do not understand the specific mechanisms of this process. In this study, we identified the effect of P4 on glucose transporter 1 (GLUT1) using in vivo animal models and determined the regulation of glucose metabolism by P4 in cells. We highly suspect that this pregnancy failure may be due to reduced GLUT1-mediated glucose metabolism, resulting in a decrease in endometrial receptivity caused by an inadequate energy supply and synthesis of substrate. Here, we propose a possible mechanism to explain how embryo implantation is affected by P4 and glucose utilization under abnormal endometrial conditions.

Annexin A1/Formyl Peptide Receptor Pathway Controls Uterine Receptivity to the Blastocyst

Embryo implantation into the uterine wall is a highly modulated, complex process. We previously demonstrated that Annexin A1 (AnxA1), which is a protein secreted by epithelial and inflammatory cells in the uterine microenvironment, controls embryo implantation in vivo. Here, we decipher the effects of recombinant AnxA1 in this phenomenon by using human trophoblast cell (BeWo) spheroids and uterine epithelial cells (Ishikawa; IK). AnxA1-treated IK cells demonstrated greater levels of spheroid adherence and upregulation of the tight junction molecules claudin-1 and zona occludens-1, as well as the glycoprotein mucin-1 (Muc-1). The latter effect of AnxA1 was not mediated through IL-6 secreted from IK cells, a known inducer of Muc-1 expression. Rather, these effects of AnxA1 involved activation of the formyl peptide receptors FPR1 and FPR2, as pharmacological blockade of FPR1 or FPR1/FPR2 abrogated such responses. The downstream actions of AnxA1 were mediated through the ERK1/2 phosphorylation pathway and F-actin polymerization in IK cells, as blockade of ERK1/2 phosphorylation reversed AnxA1-induced Muc-1 and claudin-1 expression. Moreover, FPR2 activation by AnxA1 induced vascular endothelial growth factor (VEGF) secretion by IK cells, and the supernatant of AnxA1-treated IK cells evoked angiogenesis in vitro. In conclusion, these data highlight the role of the AnxA1/FPR1/FPR2 pathway in uterine epithelial control of blastocyst implantation.

Increased Progesterone on the Day of Administration of hCG in Controlled Ovarian Hyperstimulation Affects the Expression of HOXA10 in Primates' Endometrial Receptivity

The increase in progesterone (P4) levels on the day of human chorionic gonadotropin (hCG) administration have a negative effect on endometrial receptivity. There are few reports regarding the expression of homeobox A10 (HOXA10) as one of many biomolecular factors of endometrial receptivity. To evaluate the effect of increased P4 concentration on the day of hCG administration on HOXA10, a total of 16 Macaca nemestrina were divided into three dose groups of recombinant-follicle stimulating hormone (rFSH) (30IU, 50IU, and 70IU) and one control group. Injection of rFSH combined with gonadotropin release hormone (GnRH) at 160 ug/day was given subcutaneously using a long protocol technique. Blood samples for estradiol (E2) and (P4) concentration measurements were taken on the day of injecting hCG in the final follicular phase, while the collection of endometrial tissue for HOXA10 measurement was carried out 8 to 10 days after hCG administration. E2 and P4 were measured by ELISA, whereas HOXA10 expression was measured with immunohistochemical (IHC) techniques. The concentration of E2 and P4 was found to be higher in dose groups compared with the natural group, but no significant differences were found within the group. For the Hscore for HOXA10 expression, no significant differences within dose groups were found. In addition, no significant differences for the Hscore for HOXA10 were found when compared to E2 groups. Significantly, the Hscore of HOXA10 was found to be >1 ng/mL in the P4 group compared with the Hscore HOXA10 in the P4 natural group (p = 0.022). The high concentration of P4 caused by ovarian hyperstimulation in the follicular phase stimulates the expression of HOXA10 in the secretion phase.

Regulation of Inflammation Pathways and Inflammasome by Sex Steroid Hormones in Endometriosis

Endometriosis is a gynecological disorder characterized by the growth of endometrial tissue (glands and stroma) outside the uterus, mainly in the peritoneal cavity, ovaries, and intestines. This condition shows estrogen dependency and progesterone resistance, and it has been associated with chronic inflammation, severe pain, and infertility, which negatively affect the quality of life in reproductive women. The molecular mechanisms involved in the pathogenesis of endometriosis are not completely understood; however, inflammation plays a key role in the pathophysiology of the disease, mainly by altering the function of immune cells (macrophages, natural killer, and T cells) and increasing levels of pro-inflammatory mediators in the peritoneal cavity, endometrium, and blood. These immune alterations inhibit apoptotic pathways and promote adhesion and proliferation of endometriotic cells, as well as angiogenesis and neurogenesis in endometriotic lesions. It has been demonstrated that hormonal alterations in endometriosis are related to the inflammatory unbalance in this disease. Particularly, steroid hormones (mainly estradiol) promote the expression and release of pro-inflammatory factors. Excessive inflammation in endometriosis contributes to changes of hormonal regulation by modulating sex steroid receptors expression and increasing aromatase activity. In addition, dysregulation of the inflammasome pathway, mediated by an alteration of cellular responses to steroid hormones, participates in disease progression through preventing cell death, promoting adhesion, invasion, and cell proliferation. Furthermore, inflammation is involved in endometriosis-associated infertility, which alters endometrium receptivity by impairing biochemical responses and decidualization. The purpose of this review is to present current research about the role of inflammasome in the pathogenesis of endometriosis as well as the molecular role of sex hormones in the inflammatory responses in endometriosis.

Oviductal glycoprotein 1 (OVGP1) is expressed by endometrial epithelium that regulates receptivity and trophoblast adhesion

PURPOSE

To study the regulation and functions of oviductal glycoprotein 1 (OVGP1) in endometrial epithelial cells.

METHODS

Expression of OVGP1 in mouse endometrium during pregnancy and in the endometrial epithelial cell line (Ishikawa) was studied by immunofluorescence, Western blotting, and RT-PCR. Regulation of OVGP1 in response to ovarian steroids and human chorionic gonadotropin (hCG) was studied by real-time RT-PCR. OVGP1 expression was knockdown in Ishikawa cells by shRNA, and expression of receptivity associated genes was studied by real-time RT-PCR. Adhesion of trophoblast cell line (JAr) was studied by in vitro adhesion assays.

RESULTS

OVGP1 was localized exclusively in the luminal epithelial cells of mouse endometrium at the time of embryo implantation. Along with estrogen and progesterone, hCG induced the expression of OVGP1 in Ishikawa cells. Knockdown of OVGP1 in Ishikawa cells reduced mRNA expression of ITGAV, ITGB3, ITGA5, HOXA10, LIF, and IL15; it increased the expression of HOXA11, MMP9, TIMP1, and TIMP3. Supernatants derived from OVGP1 knockdown Ishikawa cells reduced the adhesiveness of JAr cells in vitro. Expression of OVGP1 mRNA was found to be significantly lowered in the endometrium of women with recurrent implantation failure.

CONCLUSION

OVGP1 is specifically induced in the luminal epithelium at the time of embryo implantation where it regulates receptivity-related genes and aids in trophoblast adhesion.

Calpain7 impairs embryo implantation by downregulating β3-integrin expression via degradation of HOXA10

Endometriosis (ENDO) is a common gynecological disease that causes infertility in many women. Previous studies noted that the dysregulation of Homeo box A10 (HOXA10) in the endometrium of women with ENDO was involved in the failure of embryo implantation. However, the mechanism by which HOXA10 expression is reduced in women with ENDO is still poorly understood. Here we found that a member of the calcium (Ca²⁺)-dependent cysteine protease family calpain7 (CAPN7), negatively correlated with HOXA10, was highly expressed in the endometrium of infertile women with ENDO and was significantly downregulated during the window of embryo implantation in mice. Overexpression of CAPN7 in Ishikawa cells or in the uterus of mice inhibited embryo implantation in vitro and in vivo. In the current study, we identified a sequence rich in proline, glutamic acid, serine, and threonine (PEST sequence) that enhanced the Ca²⁺-dependent degradation of HOXA10 by CAPN7. Furthermore, the interaction between HOXA10 and CAPN7 repressed the transcriptional activity and protein stability of HOXA10. In contrast, the administration of the calpain inhibitor ALLN reversed the CAPN7-induced HOXA10 degradation. Moreover, truncation of the PEST motif in HOXA10 abolished its CAPN7-dependent proteolysis. These studies reveal a novel pattern of HOXA10 regulation via PEST sequence-mediated calpain proteolysis that was demonstrated to be reversed by a calpain inhibitor. Thus, the inhibition of CAPN7-induced HOXA10 degradation may represent a novel potential therapeutic method to improve impaired embryo implantation in women with ENDO.

Embryo Implantation: War in Times of Love

Contrary to widespread belief, the implantation of an embryo for the initiation of pregnancy is like a battle, in that the embryo uses a variety of coercive tactics to force its acceptance by the endometrium. We propose that embryo implantation involves a three-step process: (1) identification of a receptive endometrium; (2) superimposition of a blastocyst-derived signature onto the receptive endometrium before implantation; and finally (3) breaching by the embryo and trophoblast invasion, culminating in decidualization and placentation. We review here the story that is beginning to emerge, focusing primarily on the cells that are in "combat" during this process.

Decrease in Expression of HOXA10 in the Decidua After Embryo Implantation Promotes Trophoblast Invasion

An important step toward successful pregnancy involves invasion of the trophoblast cells into the decidua for placentation. Herein, we show that in the human and baboon decidua HOXA10 expression is downregulated after implantation and that this reduction is most prominent in the decidual cells juxtaposed to the invading placental villi. The supernatants derived from HOXA10-depleted human decidual cells increase the invasiveness of the trophoblast cell lines ACH-3P and JEG3 in vitro; this increase is due to higher expression and activity of matrix metalloproteases (MMPs) and reduced expression of tissue inhibitors of MMPs in both the cell lines. The proinvasive ability of HOXA10-depleted decidual cells is due to increased levels and secretion of leukemia inhibitor factor (LIF) and interleukin (IL)-6. Both these cytokines individually promote invasion of ACH-3P and JEG3 cell by increasing the activities of MMPs and decreasing mRNA levels of TIMPs. Finally, we demonstrate that the supernatants derived from HOXA10-depleted decidual cell-phosphorylated STAT3 (Tyr 705) and knocking down STAT3 in ACH-3P and JEG3 cells restrained the invasion mediated by supernatants derived from HOXA10-depleted decidual cells. These results imply that STAT3 activity is essential and sufficient to promote invasion in response to downregulation of HOXA10 in decidual cells. We propose that downregulation of HOXA10 in the decidual cells promotes the expression of LIF and IL-6, which, in a paracrine manner, activates STAT3 in the trophoblast cells, leading to an increase in MMPs to facilitate invasion.

Genome-wide analysis reveals signatures of selection for important traits in domestic sheep from different ecoregions

Background

Throughout a long period of adaptation and selection, sheep have thrived in a diverse range of ecological environments. Mongolian sheep is the common ancestor of the Chinese short fat-tailed sheep. Migration to different ecoregions leads to changes in selection pressures and results in microevolution. Mongolian sheep and its subspecies differ in a number of important traits, especially reproductive traits. Genome-wide intraspecific variation is required to dissect the genetic basis of these traits.

Results

This research resequenced 3 short fat-tailed sheep breeds with a 43.2-fold coverage of the sheep genome. We report more than 17 million single nucleotide polymorphisms and 2.9 million indels and identify 143 genomic regions with reduced pooled heterozygosity or increased genetic distance to each other breed that represent likely targets for selection during the migration. These regions harbor genes related to developmental processes, cellular processes, multicellular organismal processes, biological regulation, metabolic processes, reproduction, localization, growth and various components of the stress responses. Furthermore, we examined the haplotype diversity of 3 genomic regions involved in reproduction and found significant differences in TSHR and PRL gene regions among 8 sheep breeds.

Conclusions

Our results provide useful genomic information for identifying genes or causal mutations associated with important economic traits in sheep and for understanding the genetic basis of adaptation to different ecological environments.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-3212-2) contains supplementary material, which is available to authorized users.

Effect of transcutaneous electrical acupuncture point stimulation on endometrial receptivity in women undergoing frozen-thawed embryo transfer: a single-blind prospective randomised controlled trial

OBJECTIVE

To evaluate the effect of transcutaneous electrical acupuncture point stimulation (TEAS) on endometrial HOXA10 protein expression and three-dimensional (3D) power Doppler ultrasound parameters as markers of endometrial receptivity in women undergoing frozen-thawed embryo transfer (FET).

METHODS

A total of 68 women undergoing FET were randomised to receive TEAS or mock TEAS at acupuncture points CV3, CV4 and SP6 and Zigong bilaterally. Both groups had six sessions per cycle for three menstrual cycles prior to the scheduled FET. Each session lasted 30 min and was repeated every other day. 3D power Doppler ultrasound parameters, HOXA10 protein expression and rates of embryo implantation, clinical pregnancy and live birth were compared.

RESULTS

There were no significant differences between the two groups in endometrial thickness or endometrial volume. The ultrasonographic endometrial triple-line pattern was present more often in the TEAS group (p=0.002). The TEAS group had a greater endometrial and subendometrial vascularisation index (VI) than the mock TEAS group (p=0.001 and p<0.001, respectively) on 3D ultrasound and increased endometrial HOXA10 expression (p=0.001) immediately prior to FET. Subsequently, the rates of embryo implantation, clinical pregnancy and live birth rates were all higher in the TEAS group than in the mock TEAS group (p=0.024, p=0.038 and p=0.033, respectively).

CONCLUSIONS

In patients undergoing FET, TEAS may have beneficial effects on endometrial HOXA10 expression and ultrasound markers of endometrial receptivity. These findings may explain the improvement in clinical outcome of FET associated with the use of TEAS.

TRIAL REGISTRATION NUMBER

ChiCTR-TRC-14004448.

Hypermethylation of HOXA10 gene in mid-luteal endometrium from women with ovarian endometriomas

A decrease in HOXA10 gene expression in eutopic mid-secretory endometrium has been found in women with endometriosis-associated infertility. Promoter hypermethylation of HOXA10 is thought to be the leading mechanism for epigenetic gene regulation in patients with endometriosis. In our series we documented significantly higher HOXA10 promoter methylation levels in women with ovarian endometriomas than in healthy controls during the mid-luteal phase. Development of epigenetic-based strategies for non-surgical treatment of infertility related to ovarian endometriomas could be an attractive field of research in the coming years.

Interplay between Misplaced Müllerian-Derived Stem Cells and Peritoneal Immune Dysregulation in the Pathogenesis of Endometriosis

In the genetic regulation of Müllerian structures development, a key role is played by Hoxa and Wnt clusters, because they lead the transcription of different genes according to the different phases of the organogenesis, addressing correctly cell-to-cell interactions, allowing, finally, the physiologic morphogenesis. Accumulating evidence is suggesting that dysregulation of Wnt and/or Hox genes may affect cell migration during organogenesis and differentiation of Müllerian structures of the female reproductive tract, with possible dislocation and dissemination of primordial endometrial stem cells in ectopic regions, which have high plasticity to differentiation. We hypothesize that during postpubertal age, under the influence of different stimuli, these misplaced and quiescent ectopic endometrial cells could acquire new phenotype, biological functions, and immunogenicity. So, these kinds of cells may differentiate, specializing in epithelium, glands, and stroma to form a functional ectopic endometrial tissue. This may provoke a breakdown in the peritoneal cavity homeostasis, with the consequent processes of immune alteration, documented by peripheral mononuclear cells recruitment and secretion of inflammatory cytokines in early phases and of angiogenic and fibrogenic cytokines in the late stages of the disease.

HOXA10 protein expression in the endometrium of normally menstruating women after receiving GnRH antagonist

OBJECTIVE(S)

To compare HOXA10 protein expression in the endometrium between natural control cycles and GnRH antagonist-treated cycles obtained during the window of implantation of normally menstruating women.

STUDY DESIGN

This study was conducted at the Department of Obstetrics and Gynecology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. Thirty-five volunteers were recruited into this prospective, self-controlled study, which was divided into two cycles, the first a natural control cycle and the second a GnRH antagonist-treated cycle. The two cycles were separated by one resting cycle. In the GnRH antagonist-treated cycle, when the leading follicle was 15 mm, ganirelix (Orgalutran®) 0.25mg was administered daily. In both cycles, ovulation was induced when the largest follicle reached 18 mm in diameter. Finally, endometrial biopsy was performed on day 6 after documented ovulation, which corresponds to the window of implantation. Endometrial HOXA10 protein expression, a marker of endometrial receptivity, was analyzed by immunohistochemistry. The protein expression was compared between the two cycles regarding their percentage of immunostained cells and IHC-scores (percentage of stained cells×intensity of nuclear staining).

RESULTS

HOXA10 protein was exclusively localized in the stromal compartment of the endometrium. The percentage of HOXA10 nuclear staining in the endometrium collected from GnRH antagonist-treated cycles was higher than that of the natural cycles, whereas the IHC-scores showed no difference between the two cycles.

CONCLUSION(S)

GnRH antagonists may have no effect on HOXA10 protein expression in the endometrium obtained during the implantation window of normally menstruating women.