An unanticipated discourse of HB-EGF with VANGL2 signaling during embryo implantation

LIFR-Mediated ERBB2 Signaling Is Essential for Successful Embryo Implantation in Mice

In eutherian mammals, embryo implantation is a critical process for a successful pregnancy. In mice, the activation of the leukemia inhibitory factor (LIF) receptor-STAT3 signaling axis induces embryo adhesion and decidualization. The LIF receptor is believed to function as a heterodimer composed of LIFR (encoded by Lifr) and GP130 (encoded by Il6st); however, their distinct expression patterns in the uterine epithelium immediately prior to implantation suggest divergent functional roles. In this study, we generated uterine epithelium-specific Lifr knockout (Lifr eKO) mice and conducted a comprehensive gene expression analysis of the endometrium before implantation. We compared these results with those from uterine epithelium-specific Gp130 knockout (Gp130 eKO) mice. Similarly to Gp130 eKO mice, Lifr eKO mice were completely infertile. We identified 299 genes with expression changes greater than twofold following gene deletion; among these, 31 genes were downregulated and 57 genes were upregulated in both eKO models. Many of the downregulated genes were previously implicated in uterine function. Hub gene analysis identified Erbb2 and c-Fos as key regulators in both models. Further experiments using an ERBB2 inhibitor suggested that LIFR-ERBB2-mediated signaling plays a crucial role in embryo implantation.

Dysregulation of the circ-Hdac4/miR-30c/RBPJ axis in decidua impairs placental function in preeclampsia

Embryo implantation relies on complex mother-fetus interactions. Abnormal decidualization can cause various pregnancy complications such as placental abnormalities, preeclampsia, and fetal growth restriction. circRNAs play a key role in various cellular processes. This study focuses on the role of circ-Hdac4, a circRNA derived from the Hdac4 gene, in decidualization and placental function. Mouse models revealed a spatiotemporally regulated expression of circ-Hdac4 in the endometrium during early pregnancy, with enhanced expression surrounding implantation sites. In vitro and in vivo assays confirmed that circ-Hdac4 is crucial for stromal cell decidualization, as its knockdown resulted in reduced expression of decidualization markers and disrupted endometrial architecture. Furthermore, we found that circ-Hdac4 functions as a microRNA sponge for miR-30c, which negatively regulates RBPJ, a critical protein for decidual remodeling. Proteomic analysis revealed that RBPJ was downregulated upon circ-Hdac4 silencing, and we validated the direct interaction between miR-30c and RBPJ using luciferase reporter assays. A mouse preeclampsia model showed that downregulation of circ-Hdac4 during decidualization exacerbated preeclampsia-related phenotypes, including reduced fetal counts, weights, and placental weights. In addition, we observed decreased expression of circ-Hdac4 and RBPJ in the decidual surface of placental tissues from preeclampsia patients, further supporting our findings in the mouse model. Collectively, our study provides evidence that circ-Hdac4 regulates decidualization through the miR-30c-RBPJ axis and that its abnormal expression during decidualization contributes to placental dysfunction in preeclampsia. This research offers novel insights into the molecular mechanisms underlying pregnancy complications and potential therapeutic targets for their prevention and treatment.

Dysregulated miR-124-3p in endometrial epithelial cells reduces endometrial receptivity by altering polarity and adhesion

The endometrium undergoes substantial remodeling in each menstrual cycle to become receptive to an implanting embryo. Abnormal endometrial receptivity is one of the major causes of embryo implantation failure and infertility. MicroRNA-124-3p is elevated in both the serum and endometrial tissue of women with chronic endometritis, a condition associated with infertility. MicroRNA-124-3p also has a role in cell adhesion, a key function during receptivity to allow blastocysts to adhere and implant. In this study, we aimed to determine the function of microRNA-124-3p on endometrial epithelial adhesive capacity during receptivity and effect on embryo implantation. Using a unique inducible, uterine epithelial-specific microRNA overexpression mouse model, we demonstrated that elevated uterine epithelial microRNA-124-3p impaired endometrial receptivity by altering genes associated with cell adhesion and polarity. This resulted in embryo implantation failure. Similarly in a second mouse model, increasing microRNA-124-3p expression only in mouse uterine surface (luminal) epithelium impaired receptivity and led to implantation failure. In humans, we demonstrated that microRNA-124-3p was abnormally increased in the endometrial epithelium of women with unexplained infertility during the receptive window. MicroRNA-124-3p overexpression in primary human endometrial epithelial cells (HEECs) impaired primary human embryo trophectoderm attachment in a 3-dimensional culture model of endometrium. Reduction of microRNA-124-3p in HEECs from infertile women normalized HEEC adhesive capacity. Overexpression of microRNA-124-3p or knockdown of its direct target IQGAP1 reduced fertile HEEC adhesion and its ability to lose polarity. Collectively, our data highlight that microRNA-124-3p and its protein targets contribute to endometrial receptivity by altering cell polarity and adhesion.

DCAF2 is essential for the development of uterine epithelia and mouse fertility

Introduction

The successful outcome of a pregnancy depends on the proper functioning uterine epithelium. DNA damage binding protein 1 and cullin 4-associated factor 2 (DCAF2), a conserved substrate receptor for the cullin 4-RING E3 ubiquitin ligase (CRL4) complex, is essential for maintaining genome stability by facilitating ubiquitin-mediated degradation of substrates.

Methods

To better understand the physiological role of DCAF2 in female reproduction, we conducted a study using mice with conditional knockout (cKO) of DCAF2 in the uterus using the progesterone receptor Cre (Pgr Cre/+) mouse model.

Results

Our results showed the cKO mice were completely infertile, despite having ovarian function. The cKO mice exhibited severely thin uteri, demonstrating notable defects in both the uterine epithelium and a lack of glands. In addition, there were impaired proliferation and differentiation of epithelial cells in the cKO mice, ultimately resulting in failed implantation. Moreover, through deciphering the uterine transcriptome of cKO mice, we revealed crucial differentially expressed genes associated with steroid signaling. Further experiments have demonstrated cKO mice exhibit elevated uterine PGR signaling and reduced estrogen receptor signaling, although the levels of progesterone and estrogen remained unaltered. These alterations may contribute to defects in epithelium.

Discussion

Overall, our findings highlight a previously unrecognized but indispensable role for DCAF2 in the development of uterine luminal and glandular epithelium by orchestrating PGR and estrogen receptor responses. Its deficiency in the uterus leads to mouse infertility.

The Multiple Functions of HB-EGF in Female Reproduction and Related Cancer: Molecular Mechanisms and Targeting Strategies

Heparin-binding growth factor (HB-EGF) is a member of the epidermal growth factor (EGF) ligand family which has a crucial role in women's health. However, there is a lack of comprehensive review to summarize the significance of HB-EGF. Therefore, this work first described the expression patterns of HB-EGF in the endometrium and ovary of different species and gestational time. Then, the focus was on exploring how it promotes the successful implantation and regulates the process of decidualization and the function of ovarian granulosa cells as an intermediate molecule. Otherwise, we also focused on the clinical and prognostic significance of HB-EGF in female-related cancers (including ovarian cancer, cervical cancer, and endometrial cancer) and breast cancer. Lastly, the article also summarizes the current drugs targeting HB-EGF in the treatment of ovarian cancer and breast cancer. Overall, these studies found that the expression of HB-EGF in the endometrium is spatiotemporal and species-specific. And it mediates the dialogue between the blastocyst and endometrium, promoting synchronous development of the blastocyst and endometrium as an intermediate molecule. HB-EGF may serve as a potentially valuable prognostic clinical indicator in tumors. And the specific inhibitor of HB-EGF (CRM197) has a certain anti-tumor ability, which can exert synergistic anti-tumor effects with conventional chemotherapy drugs. However, it also suggests that more research is needed in the future to elucidate its specific mechanisms and to accommodate clinical studies with a larger sample size to clarify its clinical value.

3DMOUSEneST: a volumetric label-free imaging method evaluating embryo-uterine interaction and decidualization efficacy

Effective interplay between the uterus and the embryo is essential for pregnancy establishment; however, convenient methods to screen embryo implantation success and maternal uterine response in experimental mouse models are currently lacking. Here, we report 3DMOUSEneST, a groundbreaking method for analyzing mouse implantation sites based on label-free higher harmonic generation microscopy, providing unprecedented insights into the embryo-uterine dynamics during early pregnancy. The 3DMOUSEneST method incorporates second-harmonic generation microscopy to image the three-dimensional structure formed by decidual fibrillar collagen, named 'decidual nest', and third-harmonic generation microscopy to evaluate early conceptus (defined as the embryo and extra-embryonic tissues) growth. We demonstrate that decidual nest volume is a measurable indicator of decidualization efficacy and correlates with the probability of early pregnancy progression based on a logistic regression analysis using Smad1/5 and Smad2/3 conditional knockout mice with known implantation defects. 3DMOUSEneST has great potential to become a principal method for studying decidual fibrillar collagen and characterizing mouse models associated with early embryonic lethality and fertility issues.

Roles of lipid mediators in early pregnancy events

Background

Early pregnancy events, including embryo implantation, are critical for maintaining a healthy pregnancy and facilitating childbirth. Despite numerous signaling pathways implicated in establishing early pregnancy, a comprehensive understanding of implantation remains elusive.

Methods

This paper provides a comprehensive review of the current research on lipids in the context of early pregnancy, with a particular focus on feto-maternal communications.

Main Findings

Embryo implantation entails direct interaction between uterine tissues and embryos. Introducing embryos triggers significant changes in uterine epithelial morphology and stromal differentiation, facilitating embryo implantation through communication with uterine tissue. Studies employing genetic models and chemical compounds targeting enzymes and receptors have elucidated the crucial roles of lipid mediators-prostaglandins, lysophosphatidic acid, sphingosine-1-phosphate, and cannabinoids-in early pregnancy events.

Conclusion

Given the high conservation of lipid synthases and receptors across species, lipid mediators likely play pivotal roles in rodents and humans. Further investigations into lipids hold promise for developing novel diagnostic and therapeutic approaches for infertility in humans.

Transcriptomic profiling of the bovine endosalpinx and endometrium to identify putative embryokines

The objectives of the present study were to characterize the expression of genes encoding for cell signaling ligands in the bovine endosalpinx and endometrium and analyze spatial changes in gene expression. RNA sequencing was performed for the endosalpinx from the ampulla of the oviduct and endometrium from the upper and middle uterine horn and uterine body at day 2 after ovulation from ipsilateral and contralateral sides relative to the ovulatory ovary. Of the 17,827 unique mRNA transcripts mapped, 2,072 were affected by cranial-caudal position in the reproductive tract and 818 were affected by side (false discovery rate < 0.05). There were 334 genes encoding for cell signaling ligands, with 128 genes having greater than two transcripts per million on average. A total of 81 cell signaling ligand genes were affected by position and 24 were affected by side. A data set of the transcriptome of two to four cell embryos was used to identify cell signaling ligand genes that were highly expressed in the ampulla for which there was high expression of the receptor in the embryo. The most expressed ligand-receptor pairs were PSAP/SORT1, MIF/CXCR4, GPI/AMFR, and KITLG/KIT. These cell signaling ligands, as well as others whose gene is expressed in the endosalpinx and endometrium, may influence early embryonic development. Spatial changes throughout the reproductive tract highlight the distinctive expression profile of the oviduct versus the endometrium, including a set of the identified genes encoding for cell signaling ligands, and highlight the local influence of the ovary. The results also show the continuity of expression for large numbers of genes in the reproductive tract.NEW & NOTEWORTHY Examination of the transcriptome of the endosalpinx and endometrium revealed the degree to which gene expression in the reproductive tract varies spatially. The expression of genes encoding cell signaling molecules that could potentially regulate embryonic development was also identified.