The role of mesenchymal-epithelial transition in endometrial function

Aberrant TCF21 upregulation in adenomyosis impairs endometrial decidualization by increasing PDE4C expression

BACKGROUND

Impaired decidualization is a major cause of infertility in patients with adenomyosis (AM). However, the effect of transcription factor 21 (TCF21) on AM and the underlying mechanism of associated-impaired decidualization remain unclear. The aim of this study was to investigate the expression of TCF21 in endometrial tissues of AM patients and the specific mechanisms by which it impairs the decidualization of human endometrial stromal cells (HESCs), with a view to improving the reproductive outcome of AM infertile patients.

METHODS

We compared gene expressions via transcriptomics between the control and AM-associated recurrent implantation failure (RIF) groups. qRT-PCR, western blot, and IHC were performed to confirm the expression and location of TCF21 in the endometrium. Furthermore, we confirmed that high expression of TCF21 impairs decidualization by qRT-PCR, immunofluorescence, and western blot. RNA-seq following overexpression of TCF21 in HESCs was conducted to identify TCF21-related molecular changes during in vitro decidualization. Then we performed ChIP-seq/qPCR and dual-luciferase reporter assay to explore the exact interaction between TCF21 and PDE4C. The related downstream mechanisms were further proved using IHC, qRT-PCR, western blot, and ELISA.

RESULTS

According to the RNA-seq analysis, TCF21 expression was remarkably higher in the endometrium of the AM-related RIF group compared to the control group. We confirmed the same results using samples from patients with AM and controls. TCF21 overexpression in HESCs impaired decidualization through suppression of decidual markers and cytoskeleton alterations. The mechanistic analysis revealed that TCF21 inhibited intracellular cAMP levels by directly increasing PDE4C expression and suppressing FOXO1 expression.

CONCLUSIONS

TCF21 compromises decidualization in patients with AM via the PDE4C/cAMP-FOXO1 axis, which offers valuable insights on the pathology of decidualization-related infertility and indicates a potential treatment to improve endometrial receptivity in AM.

Bioactive peptides and proteins for tissue repair: microenvironment modulation, rational delivery, and clinical potential

Bioactive peptides and proteins (BAPPs) are promising therapeutic agents for tissue repair with considerable advantages, including multifunctionality, specificity, biocompatibility, and biodegradability. However, the high complexity of tissue microenvironments and their inherent deficiencies such as short half-live and susceptibility to enzymatic degradation, adversely affect their therapeutic efficacy and clinical applications. Investigating the fundamental mechanisms by which BAPPs modulate the microenvironment and developing rational delivery strategies are essential for optimizing their administration in distinct tissue repairs and facilitating clinical translation. This review initially focuses on the mechanisms through which BAPPs influence the microenvironment for tissue repair via reactive oxygen species, blood and lymphatic vessels, immune cells, and repair cells. Then, a variety of delivery platforms, including scaffolds and hydrogels, electrospun fibers, surface coatings, assisted particles, nanotubes, two-dimensional nanomaterials, and nanoparticles engineered cells, are summarized to incorporate BAPPs for effective tissue repair, modification strategies aimed at enhancing loading efficiencies and release kinetics are also reviewed. Additionally, the delivery of BAPPs can be precisely regulated by endogenous stimuli (glucose, reactive oxygen species, enzymes, pH) or exogenous stimuli (ultrasound, heat, light, magnetic field, and electric field) to achieve on-demand release tailored for specific tissue repair needs. Furthermore, this review focuses on the clinical potential of BAPPs in facilitating tissue repair across various types, including bone, cartilage, intervertebral discs, muscle, tendons, periodontal tissues, skin, myocardium, nervous system (encompassing brain, spinal cord, and peripheral nerve), endometrium, as well as ear and ocular tissue. Finally, current challenges and prospects are discussed.

LncRNA MALAT1 Knockdown Alleviates Fibrogenic Response in Human Endometrial Stromal Cells Via the miR-22-3p/TGFβR1/Smad2/3 Pathway

Intrauterine adhesion (IUA) resulting from irreversible fibrotic repair of endometrium is the main cause of secondary infertility in women, and current therapeutic approaches to IUA are limited. Increasing evidence has suggested the important role of competitive endogenous RNA (ceRNA) in IUA pathologies. This study aimed to investigate the long noncoding RNA (lncRNA) metastasis associated lung adenocarcinoma transcript 1 (MALAT1)-associated ceRNA in IUA development. We harvested endometrial tissues from patients with or without IUA and extracted endometrial stromal cells (ESCs) from normal endometrial tissues. Transforming growth factor β1 (TGF-β1) was used to induce fibrosis in ESCs. The expression of transforming growth factor β receptor 1 (TGFβR1), α-smooth muscle actin, phosphorylated suppressor of mother against decapentaplegic (p-Smad)2/3, collagen type I alpha 1, MALAT1, and microRNA (miR)-22-3p in endometrial tissues and ESCs was measured by reverse transcription quantitative polymerase chain reaction (RT-qPCR) or western blotting. Pearson's correlation analysis was conducted to assess the correlation between miR-22-3p expression or TGFβR1 and MALAT1 expression in endometrial tissues. The expression of TGFβR1 in ESCs was also evaluated by immunofluorescence staining. The location of MALAT1 was examined by fluorescence in situ hybridization. Luciferase reporter assays were performed to verify the binding relationship between MALAT1 or TGFβR1 and miR-22-3p. Cell viability was assessed via cell counting kit-8 assays. Our findings revealed that lncRNA MALAT1 and TGFβR1 were upregulated while miR-22-3p was downregulated in IUA endometrial tissues or TGF-β1-stimulated ESCs, and lncRNA MALAT1 expression was negatively correlated with miR-22-3p expression while being positively correlated with TGFβR1 expression in IUA endometrial tissues. Additionally, lncRNA MALAT1 was mainly located in the cytoplasm of ESCs and directly targeted miR-22-3p to regulate TGFβR1 expression. Moreover, knockdown of lncRNA MALAT1 exerted anti-fibrotic effects on ESCs by targeting miR-22-3p, and miR-22-3p overexpression inhibited the fibrosis of ESCs by binding to TGFβR1 3'untranslated region. Collectively, lncRNA MALAT1 promotes endometrial fibrosis by sponging miR-22-3p to regulate TGFβR1 and Smad2/3, and inhibition of MALAT1 may represent a promising therapeutic option for suppressing endometrial fibrosis.

Pharmacological and non-pharmacological interventions for improving endometrial receptivity in infertile patients with polycystic ovary syndrome: a comprehensive review of the available evidence

Direct and indirect evidence suggests that endometrial receptivity may play a crucial role in the reduced fertility rate of women with polycystic ovary syndrome (PCOS). Various pharmacological and non-pharmacological strategies with potential effects on endometrial receptivity in patients with PCOS have been proposed. The aim of this study was to summarize the rationale and the clinical and experimental evidence of interventions tested for improving endometrial receptivity in infertile patients with PCOS. A systematic review was conducted by consulting electronic databases. All interventions with a potential influence on endometrial receptivity in infertile patients with PCOS were evaluated, and their main biological mechanisms were analysed. In total, 24 interventions related to endometrial receptivity were identified. Notwithstanding a strong biological rationale, no intervention aimed at improving endometrial receptivity in women with PCOS is supported by an adequate body of evidence, limiting their use in clinical practice. Further high-quality research is needed in this field to limit potentially ineffective and unsafe add-on treatments in infertile patients with PCOS.

Acyl-CoA long-chain synthetase 1 (ACSL1) protects the endometrium from excess palmitic acid stress during decidualization

Endometrial receptivity relies on the functional and morphological change of endometrium stromal cells (EnSCs) and epithelial cells in the secretory phase. Decidualization of ESCs and transitions in endometrium epithelial cells are crucial for successful uterine implantation and maintaining pregnancy. Accumulated data have demonstrated that decidualization is tightly coordinated by lipid metabolism. However, the lipidomic change and regulatory mechanism in uterine decidualization are still unknown. Our study showed that endometrium stromal cells and decidual stromal cells had different lipidomic profiles. Acyl-CoA long-chain synthetase 1 (ACSL1) which converts fatty acids to acyl-CoA expression was strongly elevated during decidualization. ACSL1 knockdown inhibited stromal-to-decidual cell transition and decreased the decidualization markers prolactin and Insulin-like growth factor-binding protein-1 (IGFBP1) expression through the AKT pathway. Lipid uptake was upregulated in stromal cells while lipid droplet accumulation was downregulated during decidualization. Meanwhile, silencing of ACSL1 led to impaired spare respiratory capacity, and downregulation of TFAM expression, indicating robust lipid metabolism. While palmitic acid addition impeded decidualization, overexpression of ACSL1 could partially reverse its effect. ACSL inhibitor Triacsin C significantly impeded decidualization in a three-dimensional coculture model consisting of endometrial stromal cells and epithelial cells. Knockdown of ACSL1 in stromal cells decreased the expression of the decidualization markers PAEP and SPP1 in epithelial cells. Collectively, ACSL1 is essential for uterine decidualization and protects stromal cells from excess palmitic acid stress.

CDC42 deficiency leads to endometrial stromal cell senescence in recurrent implantation failure

STUDY QUESTION

Does the downregulation of cell division cycle 42 (CDC42) protein in endometrial stroma lead to endometrial senescence in patients with recurrent implantation failure (RIF), and what is the potential mechanism?

SUMMARY ANSWER

CDC42 deficiency causes endometrial stromal senescence and decidualization defects, impairing uterine receptivity of RIF patients, via activation of Wnt signaling pathway.

WHAT IS KNOWN ALREADY

Uterine aging is unique due to the cyclic remodeling and decidualization of endometrial tissue. Several transcriptomic studies have reported increased senescence in the endometrium in young patients with RIF. Our previous transcriptomic sequencing study discovered that endometrium from women with RIF showed downregulation of CDC42, which is an essential molecule affected by various senescence-related diseases.

STUDY DESIGN, SIZE, DURATION

The endometrial samples of a total of 71 fertile control patients and 37 RIF patients were collected to verify the association between CDC42 expression and endometrial senescence of RIF patients. Primary endometrial stromal cells (EnSCs) were isolated from endometrial biopsies taken from patients without any endometrial complications and planning to undergo IVF, then subjected to adenovirus-mediated CDC42 knockdown and decidualization induction to explore the detailed mechanism by which CDC42 governs stromal senescence and decidualization. Wnt inhibitor XAV-939 was used to correct the endometrial senescence and decidualization defect.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Senescence was determined by cell cycle arrest markers (e.g. P16, P21, and P53), SASP molecules (e.g. IL6 and CXCL8), and SA-β-gal staining. Masson's staining and Sirius Red staining were used to detect the endometrial fibrosis. Decidualization was evaluated by the mRNA expression and protein secretion of PRL and IGFBP1, F-actin immunostaining, and the BeWo spheroids 'in vitro implantation' model. Methods used to assess cell function included adenovirus transduction, RNA-sequencing, bioinformatic analysis, western blotting, RT-qPCR, ELISA, and immunofluorescence.

MAIN RESULTS AND THE ROLE OF CHANCE

Here, we observed remarkably increased levels of stromal senescence and fibrosis, along with stromal CDC42 deficiency, in the endometrium of patients with RIF (P < 0.001). Knockdown of CDC42 effectively induced premature senescence in EnSCs, leading to aberrant accumulation of senescent EnSCs and collagen deposition during decidualization. CDC42 deficiency in EnSCs restrained the decidualization differentiation and receptivity to trophoblast cells. Transcriptomic analysis revealed Wnt signaling activation as a critical downstream alteration in CDC42-deficient EnSCs. Mechanistically, CDC42 interacted with AKT competitively to impede the binding of GSK3β to AKT. Knockdown of CDC42 increased AKT-mediated phosphorylation of GSK3β to inactivate the Axin-GSK3β destruction complex, leading to accumulation and nuclear translocation of β-catenin. Importantly, Wnt signaling inhibitors partially corrected the endometrial senescence caused by CDC42 deficiency, and improved both decidualization and trophoblast invasion.

LARGE SCALE DATA

RNA-seq data sets generated in this study have been deposited at the NCBI database with BioProject accession number PRJNA1102745.

LIMITATIONS, REASONS FOR CAUTION

The present study was based on in vitro cell cultures. Further studies involving CDC42-regulated endometrial senescence are needed in knockout mice model and human endometrial assembloids.

WIDER IMPLICATIONS OF THE FINDINGS

In addition to uncovering endometrial senescence in RIF, our findings underscore the significance of CDC42 in modulating EnSC senescence to maintain the decidualization function, and suggest Wnt signaling inhibitors as potential therapeutic agents for alleviating endometrial senescence.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Natural Science Foundation of China [82271698 (R.J.), 82030040 (H.S.), 82288102 (H.W.), and 82371680 (G.Y.)]; the Natural Science Foundation of Jiangsu Province [BK20231117 (R.J.)]; and the Medical Science and Technology Development Foundation of Nanjing Department of Health [YKK23097 (Y.Z.)]. The authors declare no potential conflicts of interest.

Expression and Hormonal Regulation of Entpd3 at Various Estrous Cycle Stages in the Mouse Uterus

Ectonucleoside triphosphate diphosphohydrolase 3 (ENTPD3), a plasma membrane-bound metabolic enzyme, converts extracellular nucleotides into nucleosides. ENTPD3 is involved in various pathophysiological processes, including cellular adhesion, metabolism, activation, and migration. However, its specific function in the uterus remains unclear. This study aimed to investigate the expression pattern and localization of Entpd3 in the mouse uterus throughout the estrous cycle using immunohistochemistry (IHC), quantitative real-time PCR, and western blot analysis. The effect of sex steroid hormones on Entpd3 expression was also examined in ovariectomized (OVX) mice treated with 17β-estradiol (E2)/progesterone (P4) and estrogen receptor antagonist (Fulvestrant)/progesterone receptor antagonist (Mifepristone). Results demonstrated that elevated levels of Entpd3 mRNA and protein were noted during estrus and metestrus, with a decline in diestrus and proestrus. IHC revealed abundant ENTPD3 in the cytoplasm of glandular and luminal epithelial cells during estrus and metestrus. Additionally, treatment with E2 or P4 in OVX mice downregulated the expression of Entpd3 in the mouse uterus, which was rescued by Fulvestrant or Mifepristone. This study demonstrated that the expression of Entpd3 in the mouse uterus varied dynamically throughout the estrous cycle and was steroid-dependent, suggesting a potential role for Entpd3 in female mice's reproductive function.

Hydrogel Strategies for Female Reproduction Dysfunction

Infertility is an important issue for human reproductive health, with over half of all cases of infertility associated with female factors. Dysfunction of the complex female reproductive system may cause infertility. In clinical practice, female infertility is often treated with oral medications and/or surgical procedures, and ultimately with assisted reproductive technologies. Owing to their excellent biocompatibility, low immunogenicity, and adjustable mechanical properties, hydrogels are emerging as valuable tools in the reconstruction of organ function, supplemented by tissue engineering techniques to increase their structure and functionality. Hydrogel-based female reproductive reconstruction strategies targeting the pathological mechanisms of female infertility may provide alternatives for the treatment of ovarian, endometrium/uterine, and fallopian tube dysfunction. In this review, we provide a general introduction to the basic physiology and pathology of the female reproductive system, the limitations of current infertility treatments, and the lack of translation from animal models to human reproductive physiology. We further provide an overview of the current and future potential applications of hydrogels in the treatment of female reproductive system dysfunction, highlighting the great prospects of hydrogel-based strategies in the field of translational medicine, along with the significant challenges to be overcome.

Current advances in understanding endometrial epithelial cell biology and therapeutic applications for intrauterine adhesion

The human endometrium is a highly regenerative tissue capable of undergoing scarless repair during the menstruation and postpartum phases. This process is mediated by endometrial adult stem/progenitor cells. During the healing of endometrial injuries, swift reepithelization results in the rapid covering of the wound surface and facilitates subsequent endometrial restoration. The involvement of endogenous endometrial epithelial stem cells, stromal cells, and bone marrow-derived cells in the regeneration of the endometrial epithelium has been a subject of prolonged debate. Increasing evidence suggests that the regeneration of the endometrial epithelium mainly relies on epithelial stem cells rather than stromal cells and bone marrow-derived cells. Currently, no consensus has been established on the identity of epithelial stem cells in the epithelial compartment. Several markers, including stage-specific embryonic antigen-1 (SSEA-1), sex-determining region Y-box 9 (SOX9), neural-cadherin (N-cadherin), leucine-rich-repeat-containing G-protein-coupled receptor 5 (LGR5), CD44, axis inhibition protein 2 (Axin2), and aldehyde dehydrogenase 1A1 (ALDH1A1), have been suggested as potential candidate markers for endometrial epithelial stem cells. The identification of endometrial epithelial stem cells contributes to our understanding of endometrial regeneration and offers new therapeutic insights into diseases characterized by regenerative defects in the endometrium, such as intrauterine adhesion. This review explores different perspectives on the origins of human and mouse endometrial epithelial cells. It summarizes the potential markers, locations, and hierarchies of epithelial stem cells in both human and mouse endometrium. It also discusses epithelial cell-based treatments for intrauterine adhesion, hoping to inspire further research and clinical application of endometrial epithelial stem cells.

Emerging Roles of IL-27 in Trophoblast Cells and Pregnancy Complications

PROBLEM

Pregnancy complications such as spontaneous abortion, preeclampsia, and preterm birth persist, despite current interventions aimed at their prevention and treatment largely proving unsuccessful. Interleukin-27 (IL-27), composed of p28 and EBI3 subunits, binds to IL-27R, which consists of gp130 and IL-27Rα (also known as WSX-1 or TCCR), and plays a pivotal role in tumor development and inflammation regulation. At the maternal-fetal interface, IL-27 expression has been detected in trophoblasts, endometrial stromal cells, and decidual cells. Abnormal levels of IL-27/IL-27R have been linked to adverse pregnancy outcomes, including spontaneous miscarriage, preeclampsia, and preterm birth. This review aims to explore the expression of IL-27 at the maternal-fetal interface and its signaling pathway, uncovering the complex role of IL-27 in pregnancy complications.

METHOD OF STUDY

A comprehensive literature review was conducted using PubMed/Medline, Scopus, and Embase databases, analyzing studies on IL-27 expression and its signaling pathways at the maternal-fetal interface. The review focused on identifying the presence of IL-27 in various cell types and linking abnormal IL-27/IL-27R expression to pregnancy complications such as spontaneous miscarriage, preeclampsia, and preterm birth.

DISCUSSION AND CONCLUSION

IL-27 plays a complex role at the maternal-fetal interface, with abnormal expression linked to several pregnancy complications. These findings highlight the need for further research to elucidate IL-27's mechanisms and develop targeted interventions. Future studies should aim to develop targeted interventions and improve therapeutic strategies for managing pregnancy complications.

Quantitative Assessment of Polarization and Elastic Properties of Endometrial Tissue for Precancer/Cancer Diagnostics Using Multimodal Optical Coherence Tomography

Objectives: The most important phase in the endometrial pathologies diagnostics is the histological examination of tissue biopsies obtained under visual hysteroscopic control. However, the unclear visual diagnostics characteristics of subtle focal endometrial pathologies often lead to selection errors regarding suspicious endometrial lesions and to a subsequent false pathological diagnosis/underestimation of precancer or early-stage cancer. Methods: In this study, we investigate the potential of Multimodal Optical Coherence Tomography (MM OCT) to verify suspicious endometrial lesion regions before biopsy collection. We study the polarization (by cross-polarization OCT, CP OCT) and elastic (by compression OCT-elastography, C-OCE) properties of ex vivo endometrial tissue samples in normal conditions (proliferative and secretory phases to the menstrual cycle, atrophic endometrium) with endometrial hyperplasia (non-atypical and endometrial intraepithelial neoplasia) and endometrial cancer subtypes (low-grade, high-grade, clear cell and serous). Results: To the best of our knowledge, this is the first quantitative assessment of relevant OCT parameters (depth-resolved attenuation coefficient in co-[Att(co) values] and cross-[(Att(cross) values] polarizations and Young's elastic modulus [stiffness values]) for the selection of the most objective criteria to identify the clinically significant endometrial pathologies: endometrial intraepithelial neoplasia and endometrial cancer. The study demonstrates the possibility of detecting endometrial pathologies and establishing optimal threshold values of MM OCT criteria for the identification of endometrial cancer using CP OCT (by Att(co) values = 3.69 mm-1, Sensitivity (Se) = 86.1%, Specificity (Sp) = 92.6%; by Att(cross) values = 2.27 mm-1, Se = 86.8%, Sp = 87.0%) and C-OCE (by stiffness values = 122 kPa, Se = 93.2%, Sp = 91.1%). The study also differentiates endometrial intraepithelial neoplasia from non-atypical endometrial hyperplasia and normal endometrium using C-OCE (by stiffness values = 95 kPa, Se = 87.2%, Sp = 90.1%). Conclusions: The results are indicative of the efficacy and potential of clinical implementation of in vivo hysteroscopic-like MM OCT in the diagnosis of endometrial pathologies.

Paclitaxel hyperthermia suppresses gastric cancer migration through MiR-183-5p/PPP2CA/AKT/GSK3β/β-catenin axis

BACKGROUND

Gastric cancer (GC), a prevalent malignant tumor which is a leading cause of death from malignancy around the world. Peritoneal metastasis accounts for the major cause of mortality in patients with GC. Despite hyperthermia intraperitoneal chemotherapy (HIPEC) improves the therapeutic effect of GC, it's equivocal about the mechanism under HIPEC.

METHODS

MiR-183-5p expression was sifted from miRNA chip and detected in both GC patients and cell lines by qRT-PCR. Gene interference and rescue experiments were performed to identified biological function in vitro and vivo. Next, we affirmed PPP2CA as targeted of miR-183-5p by dual luciferase reporter assay. Finally, the potential relationship between HIPEC and miR-183-5p was explored.

RESULTS

MiR-183-5p is up-regulated in GC and associated with advanced stage and poor prognosis. MiR-183-5p accelerate GC migration in vitro which is influenced by miR-183-5p/PPP2CA/AKT/GSK3β/β-catenin Axis. HIPEC exerts migration inhibition via attenuating miR-183-5p expression.

CONCLUSION

MiR-183-5p can be used as a potential HIPEC biomarker in patients with CC.

Epithelial-Mesenchymal Transition Related Score Functions as a Predictive Tool for Immunotherapy and Candidate Drugs in Glioma

Gliomas are aggressive CNS tumors where the epithelial-mesenchymal transition (EMT) is crucial for prognosis. We developed an EMT-based score predicting overall survival (OS) and conducted pathway analyses, revealing functions such as cell proliferation and immune response in glioma progression. The EMT score, correlated with immune functions and cell infiltration, shows potential as an immune response indicator. We identified two promising compounds, BIX02189 and QL-XI-92, as potential glioma treatments based on candidate gene analysis.

Aging promotes accumulation of senescent and multiciliated cells in human endometrial epithelium

STUDY QUESTION

What changes occur in the endometrium during aging, and do they impact fertility?

SUMMARY ANSWER

Both the transcriptome and cellular composition of endometrial samples from women of advanced maternal age (AMA) are significantly different from that of samples from young women, suggesting specific changes in epithelial cells that may affect endometrial receptivity.

WHAT IS KNOWN ALREADY

Aging is associated with the accumulation of senescent cells in aging tissues. Reproductive aging is mostly attributed to the decline in ovarian reserve and oocyte quality, whereas the endometrium is a unique complex tissue that is monthly renewed under hormonal regulation. Several clinical studies have reported lower implantation and pregnancy rates in oocyte recipients of AMA during IVF. Molecular studies have indicated the presence of specific mutations within the epithelial cells of AMA endometrium, along with altered gene expression of bulk endometrial tissue.

STUDY DESIGN SIZE DURATION

Endometrial transcriptome profiling was performed for 44 women undergoing HRT during the assessment of endometrial receptivity before IVF. Patients younger than 28 years were considered as the young maternal age (YMA) group (age 23-27 years) and women older than 45 years were considered as the AMA group (age 47-50 years). Endometrial biopsies were obtained on Day 5 of progesterone treatment and RNA was extracted. All endometrial samples were evaluated as being receptive based on the expression of 68 common endometrial receptivity markers. Endometrial samples from another 24 women classified into four age groups (YMA, intermediate age group 1 (IMA1, age 29-35), intermediate age group 2 (IMA2, age 36-44), and AMA) were obtained in the mid-secretory stage of a natural cycle (NC) and used for validation studies across the reproductive lifespan.

PARTICIPANTS/MATERIALS SETTING METHODS

A total of 24 HRT samples (12 YMA and 12 AMA) were subject to RNA sequencing (RNA-seq) and differential gene expression analysis, 20 samples (10 YMA and 10 AMA) were used for qPCR validation, and 24 NC samples (6 YMA, 6 IMA1, 6 IMA2 and 6AMA) were used for RNA-seq validation of AMA genes across the woman's reproductive lifespan. Immunohistochemistry (IHC) was used to confirm some expression changes at the protein level. Computational deconvolution using six endometrial cell type-specific transcriptomic profiles was conducted to compare the cellular composition between the groups.

MAIN RESULTS AND THE ROLE OF CHANCE

Comparisons between YMA and AMA samples identified a lower proportion of receptive endometria in the AMA group (P = 0.007). Gene expression profiling identified 491 differentially expressed age-sensitive genes (P adj < 0.05) that revealed the effects of age on endometrial epithelial growth and receptivity, likely contributing to decreased reproductive performance. Our results indicate that changes in the expression of the cellular senescence marker p16INK4a and genes associated with metabolism, inflammation, and hormone response are involved in endometrial aging. Importantly, we demonstrate that the proportion of multi-ciliated cells, as discovered based on RNA-seq data deconvolution and tissue IHC results, is affected by endometrial aging, and propose a putative onset of age-related changes. Furthermore, we propose that aging has an impact on the transcriptomic profile of endometrial tissue in the context of endometrial receptivity.

LARGE SCALE DATA

The raw sequencing data reported in this article are deposited at the Gene Expression Omnibus under accession code GSE236128.

LIMITATIONS REASONS FOR CAUTION

This retrospective study identified changes in the endometrium of patients undergoing hormonal replacement and validated these changes using samples obtained during a NC. However, future studies must clarify the importance of these findings on the clinical outcomes of assisted reproduction.

WIDER IMPLICATIONS OF THE FINDINGS

The findings reported in this study have important implications for devising future strategies aimed at improving fertility management in women of advanced reproductive age.

STUDY FUNDING/COMPETING INTERESTS

This research was funded by the Estonian Research Council (grant no. PRG1076), Horizon 2020 innovation grant (ERIN, grant no. EU952516), Enterprise Estonia (grant no. EU48695), MSCA-RISE-2020 project TRENDO (grant no. 101008193), EU 874867 project HUTER, the Horizon Europe NESTOR grant (grant no. 101120075) of the European Commission, the EVA specialty program (grant no. KP111513) of the Maastricht University Medical Center (MUMC+), MICIU/AEI/10.13039/501100011033 and FEDER, EU projects Endo-Map (grant no. PID2021-12728OB-100), ROSY (grant no. CNS2022-135999), and the National Science Fund of Bulgaria (grant no. KII-06 H31/2). The authors declare no competing interests.

Particulate matter exposure induces adverse effects on endometrium and fertility via aberrant inflammatory and apoptotic pathways in vitro and in vivo

This study aimed to evaluate the adverse effects of particulate matter (PM) exposure on endometrial cells and fertility and to identify possible underlying mechanisms. Thirteen women (aged 15-52 years) were included in this study. Enrolled patients underwent laparoscopic surgery at Gangnam Severance Hospital between 1 January and 31 December 2021. For in vivo experiments, 36 female and nine male C57BL/6 mice were randomly divided into control(vehicle), low-dose(10 mg/kg/d), and high-dose exposure groups(20 mg/kg/d). PM was inhaled nasally for four weeks and natural mating was performed. NIST® SRM® 1648a was used for PM exposure. qRT-PCR, western blotting and Masson's trichrome staining were performed. PM treatment in human endometrial stromal cells induced inflammation with significant upregulation of IL-1β, p-NF-kB, and p-c-Jun compared to those of controls. Additionally, PM treatment significantly increased apoptosis in human endometrial stromal cells by downregulating p-AKT and upregulating p-p53/p53, Cas-3, BAX/Bcl-2, p-AMPK, and p-ERK. After PM treatment, the relative expression of IL-1β, IL-6, TNF-α, p-NF-κB, p-c-Jun, and p-Nrf2/Nrf2 significantly increased in murine endometrium compared to those of the controls. Expression of apoptotic proteins p53, p27, and Cas-3, was also significantly elevated in murine endometrium of the PM exposure group compared to that of the controls. A significant increase in expression of procollagen Ⅰ, and Masson's trichrome staining scores in the murine endometrium was noted after PM treatment. PM treatment significantly decreased ERα expression. After natural mating, all 3 female mice in the control group gave birth to 25 offspring (mean 8.1), whereas in the low-dose PM treatment group, two of three female mice gave birth to nine offspring (mean 4.5). No pregnant mice or offspring was present in the high-dose PM treatment group. PM exposure induces adverse effects on the endometrium through aberrant activation of inflammatory and apoptotic pathways and is associated with detrimental effects on murine fertility.

Decreased AMPK/SIRT1/PDK4 induced by androgen excess inhibits human endometrial stromal cell decidualization in PCOS

Polycystic ovary syndrome (PCOS) is a complex common endocrine disorder affecting women of reproductive age. Ovulatory dysfunction is recognized as a primary infertile factor, however, even when ovulation is medically induced and restored, PCOS patients continue to experience reduced cumulative pregnancy rates and a higher spontaneous miscarriage rate. Hyperandrogenism, a hallmark feature of PCOS, affects ovarian folliculogenesis, endometrial receptivity, and the establishment and maintenance of pregnancy. Decidualization denotes the transformation that the stromal compart of the endometrium must undergo to accommodate pregnancy, driven by the rising progesterone levels and local cAMP production. However, studies on the impact of hyperandrogenism on decidualization are limited. In this study, we observed that primary endometrial stromal cells from women with PCOS exhibit abnormal responses to progesterone during in vitro decidualization. A high concentration of testosterone inhibits human endometrial stromal cells (HESCs) decidualization. RNA-Seq analysis demonstrated that pyruvate dehydrogenase kinase 4 (PDK4) expression was significantly lower in the endometrium of PCOS patients with hyperandrogenism compared to those without hyperandrogenism. We also characterized that the expression of PDK4 is elevated in the endometrium stroma at the mid-secretory phase. Artificial decidualization could enhance PDK4 expression, while downregulation of PDK4 leads to abnormal decidualization both in vivo and in vitro. Mechanistically, testosterone excess inhibits IGFBP1 and PRL expression, followed by phosphorylating of AMPK that stimulates PDK4 expression. Based on co-immunoprecipitation analysis, we observed an interaction between SIRT1 and PDK4, promoting glycolysis to facilitate decidualization. Restrain of AR activation resumes the AMPK/SIRT1/PDK4 pathway suppressed by testosterone excess, indicating that testosterone primarily acts on decidualization through AR stimulation. Androgen excess in the endometrium inhibits decidualization by disrupting the AMPK/SIRT1/PDK4 signaling pathway. These data demonstrate the critical roles of endometrial PDK4 in regulating decidualization and provide valuable information for understanding the underlying mechanism during decidualization.

Unraveling the Dynamics of Estrogen and Progesterone Signaling in the Endometrium: An Overview

The endometrium is crucial for the perpetuation of human species. It is a complex and dynamic tissue lining the inner wall of the uterus, regulated throughout a woman's life based on estrogen and progesterone fluctuations. During each menstrual cycle, this multicellular tissue undergoes cyclical changes, including regeneration, differentiation in order to allow egg implantation and embryo development, or shedding of the functional layer in the absence of pregnancy. The biology of the endometrium relies on paracrine interactions between epithelial and stromal cells involving complex signaling pathways that are modulated by the variations of estrogen and progesterone levels across the menstrual cycle. Understanding the complexity of estrogen and progesterone receptor signaling will help elucidate the mechanisms underlying normal reproductive physiology and provide fundamental knowledge contributing to a better understanding of the consequences of hormonal imbalances on gynecological conditions and tumorigenesis. In this narrative review, we delve into the physiology of the endometrium, encompassing the complex signaling pathways of estrogen and progesterone.

Mapping Single-Cell Transcriptomes of Endometrium Reveals Potential Biomarkers in Endometrial Cancer

Background

The heterogeneity and dynamic changes of endometrial cells have a significant impact on health as they determine the normal function of the endometrium during the menstrual cycle. Dysfunction of the endometrium can lead to the occurrence of various gynecological diseases. Therefore, deconvolution of immune microenvironment that drives transcriptional programs throughout the menstrual cycle is key to understand regulatory biology of endometrium.

Methods

Herein, we comprehensively analyzed single-cell transcriptome of 59,397 cells across ten human endometrium samples and revealed the dynamic cellular heterogeneity throughout the menstrual cycle.

Results

We identified two perivascular cell subtypes, four epithelial subtypes and four fibroblast cell types in endometrium. Moreover, we inferred the cell type-specific transcription factor (TF) activities and linked critical TFs to transcriptional output of diverse immune cell types, highlighting the importance of transcriptional regulation in endometrium. Dynamic interactions between various types of cells in endometrium contribute to a range of biological pathways regulating differentiation of secretory. Integration of the molecular biomarkers identified in endometrium and bulk transcriptome of 535 endometrial cancers (EC), we revealed five RNA-based molecular subtypes of EC with highly intratumoral heterogeneity and different clinical manifestations. Mechanism analysis uncovered clinically relevant pathways for pathogenesis of EC.

Conclusion

In summary, our results revealed the dynamic immune microenvironment of endometrium and provided novel insights into future development of RNA-based treatments for endometriosis and endometrial carcinoma.

Nuclear actin assembly is an integral part of decidualization in human endometrial stromal cells

Decidualization of the human endometrium is critical for establishing pregnancy and is entailed by differentiation of endometrial stromal cells (ESCs) into decidual cells. During decidualization, the actin cytoskeleton is dynamically reorganized for the ESCs' morphological and functional changes. Although actin dynamically alters its polymerized state upon external stimuli not only in the cytoplasm, but also in the nucleus, nuclear actin dynamics during decidualization have not been elucidated. Here, we show that nuclear actin was specifically assembled during decidualization of human ESCs. This decidualization-specific formation of nuclear actin filaments was disassembled following the withdrawal of the decidualization stimulus, suggesting its reversible process. Mechanistically, RNA-seq analyses revealed that the forced disassembly of nuclear actin resulted in the suppression of decidualization, accompanied with the abnormal upregulation of cell proliferation genes, leading to incomplete cell cycle arrest. CCAAT/enhancer-binding protein beta (C/EBPβ), an important regulator for decidualization, was responsible for downregulation of the nuclear actin exporter, thus accelerating nuclear actin accumulation and its assembly for decidualization. Taken together, we demonstrate that decidualization-specific nuclear actin assembly induces cell cycle arrest for establishing the decidualized state of ESCs. We propose that not only the cytoplasmic actin, but also nuclear actin dynamics profoundly affect decidualization process in humans for ensuring pregnancy.

The Endometrial Stem/Progenitor Cells and Their Niches

Endometrial stem/progenitor cells are a type of stem cells with the ability to self-renew and differentiate into multiple cell types. They exist in the endometrium and form niches with their neighbor cells and extracellular matrix. The interaction between endometrial stem/progenitor cells and niches plays an important role in maintaining, repairing, and regenerating the endometrial structure and function. This review will discuss the characteristics and functions of endometrial stem/progenitor cells and their niches, the mechanisms of their interaction, and their roles in endometrial regeneration and diseases. Finally, the prospects for their applications will also be explored.

Cryptochrome 2 Suppresses Epithelial-Mesenchymal Transition by Promoting Trophoblastic Ferroptosis in Unexplained Recurrent Spontaneous Abortion

Unexplained recurrent spontaneous abortion (URSA) is a serious reproductive issue that affects women of childbearing age. Studies have shown a close association between disrupted circadian rhythm and impaired epithelial-mesenchymal transition (EMT) in trophoblasts during URSA, although the underlying mechanism is not known. The current study investigated the regulatory relationship between circadian rhythm gene cryptochrome 2 (CRY2) and ferroptosis on the migratory ability of trophoblast cells. Cell proliferation experiments, wound-healing assays, and expression of related markers were conducted to study EMT. Trophoblastic ferroptosis was confirmed by the expressions of malondialdehyde, glutathione, mitochondrial membrane potential, divalent iron ions, and related genes. The results showed significant increased expression of CRY2 and decreased expression of brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) in the URSA villous tissues, accompanied by iron-dependent oxidative changes and abnormal expression of ferroptosis-related proteins. CRY2 and BMAL1 were co-localized and functioned as a feedback loop, which regulated the dynamic changes of EMT-related markers in trophoblast cells. CRY2 promoted trophoblastic ferroptosis, whereas BMAL1 had the opposite effect. Particularly, the ferroptosis inhibitor (ferrostatin-1) effectively reversed the trophoblastic ferroptosis and EMT inhibition caused by CRY2 overexpression. Collectively, these results suggest that CRY2 regulates trophoblastic ferroptosis and hinders cellular EMT and migratory ability by suppressing BMAL1 expression.

Early short-term hypoxia promotes epidermal cell migration by activating the CCL2-ERK1/2 pathway and epithelial-mesenchymal transition during wound healing

Background

Due to vasculature injury and increased oxygen consumption, the early wound microenvironment is typically in a hypoxic state. We observed enhanced cell migration ability under early short-term hypoxia. CCL2 belongs to the CC chemokine family and was found to be increased in early hypoxic wounds and enriched in the extracellular signal-regulated kinase (ERK)1/2 pathway in our previous study. However, the underlying mechanism through which the CCL2-ERK1/2 pathway regulates wound healing under early short-term hypoxia remains unclear. Activation of epithelial-mesenchymal transition (EMT) is a key process in cancer cell metastasis, during which epithelial cells acquire the characteristics of mesenchymal cells and enhance cell motility and migration ability. However, the relationship between epithelial cell migration and EMT under early short-term hypoxia has yet to be explored.

Methods

HaCaT cells were cultured to verify the effect of early short-term hypoxia on migration through cell scratch assays. Lentiviruses with silenced or overexpressed CCL2 were used to explore the relationship between CCL2 and migration under short-term hypoxia. An acute full-thickness cutaneous wound rat model was established with the application of an ERK inhibitor to reveal the hidden role of the ERK1/2 pathway in the early stage of wound healing. The EMT process was verified in all the above experiments through western blotting.

Results

In our study, we found that short-term hypoxia promoted cell migration. Mechanistically, hypoxia promoted cell migration through mediating CCL2. Overexpression of CCL2 via lentivirus promoted cell migration, while silencing CCL2 via lentivirus inhibited cell migration and the production of related downstream proteins. In addition, we found that CCL2 was enriched in the ERK1/2 pathway, and the application of an ERK inhibitor in vivo and in vitro verified the upstream and downstream relationships between the CCL2 pathway and ERK1/2. Western blot results both in vivo and in vitro demonstrated that early short-term hypoxia promotes epidermal cell migration by activating the CCL2-ERK1/2 pathway and EMT during wound healing.

Conclusions

Our work demonstrated that hypoxia in the early stage serves as a stimulus for triggering wound healing through activating the CCL2-ERK1/2 pathway and EMT, which promote epidermal cell migration and accelerate wound closure. These findings provide additional detailed insights into the mechanism of wound healing and new targets for clinical treatment.

Autophagy genes and signaling pathways in endometrial decidualization and pregnancy complications

Autophagy is a process that occurs in almost all eukaryotic cells and this process is controlled by several molecular processes. Its biological roles include the provision of energy, the maintenance of cell homeostasis, and the promotion of aberrant cell death. The importance of autophagy in pregnancy is gradually becoming recognized. In literature, it has been indicated that autophagy has three different effects on the onset and maintenance of pregnancy: embryo (embryonic development), feto-maternal immune crosstalk, and maternal (decidualization). In humans, proper decidualization is a major predictor of pregnancy accomplishment and it can be influenced by different factors. This review highlights the genes, pathways, regulation, and function of autophagy in endometrial decidualization and other involved factors in this process.

Excessive proliferating cell nuclear antigen attenuates endometrial adhesive capacity and decidualization in patients with recurrent implantation failure

STUDY QUESTION

Does the expression of proliferating cell nuclear antigen (PCNA) in the endometrium regulate endometrial receptivity in patients with recurrent implantation failure (RIF)?

SUMMARY ANSWER

A high abundance of PCNA attenuates endometrial adhesive capacity and decidualization in patients with RIF.

WHAT IS KNOWN ALREADY

Aberrant expression of PCNA has been discovered in multiple infertility-related disorders. However, the expression pattern and role of PCNA in the establishment of endometrial receptivity and endometrial decidualization in patients with RIF remain unclear.

STUDY DESIGN, SIZE, DURATION

We analysed the expression of PCNA in mid-secretory endometrial tissues from 24 patients with RIF and 24 healthy women. Additionally, PCNA expression levels were measured in proliferative and mid-secretory phase endometrial tissue samples from women with regular menstrual cycles and in decidual tissue samples taken from ten women during normal early pregnancy (n = 10 per phase for each group). The function and regulatory mechanisms of PCNA in endometrial adhesive capacity and endometrial decidualization were investigated using BeWo spheroids, Ishikawa cells, and human endometrial stromal cells (HESCs).

PARTICIPANTS/MATERIALS, SETTING, METHODS

The expression of PCNA in mid-secretory endometrial tissues of patients with RIF and women with normal endometrium and in endometrial tissue at different stages of the menstrual cycle and in decidualized tissues was analysed by RT-qPCR, western blot, and immunohistochemistry staining (IHC). Furthermore, the number of BeWo spheroids directly attached to the Ishikawa cell monolayers, and the potential molecular mechanisms involved, were compared between cells overexpressing PCNA and a control group. Additionally, the effect and regulatory mechanisms of PCNA on the decidualization of HESCs in vitro were investigated.

MAIN RESULTS AND THE ROLE OF CHANCE

Our findings indicated that the abundance of PCNA was dramatically greater in mid-secretory endometrial tissues from patients with RIF than in those from women with healthy endometrium. The expression of PCNA increased in the proliferative phase of the menstrual cycle but decreased gradually in the mid-secretory phase and in decidual tissues. Interestingly, PCNA was expressed in both human endometrial epithelial cells (HEECs) and HESCs. In Ishikawa cells, PCNA overexpression dramatically reduced the endometrial adhesive capacity by inhibiting the expression of adhesion molecules (E-cadherin and integrin β3) and activating the FAK/paxillin signalling pathway. Furthermore, in HESCs, PCNA overexpression attenuated endometrial decidualization by activating the AKT/β-catenin signalling pathway and increasing tight junctions between cells by upregulating ZO-1 and occludin expression. In addition, PCNA-ELAVL1 interactions were confirmed by coimmunoprecipitation in decidualized HESCs.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The functional analysis of PCNA was limited by the number of human endometrial tissues. A larger sample size is required to further explore the potential roles of PCNA during embryo implantation. Moreover, the present results should be taken with caution, as only a few of the embryos that were transferred in RIF patients population underwent preimplantation genetic testing for embryonic chromosome aneuploidies (PGT-A), despite embryo ploidy testing being significant in the diagnosis of unexplained RIF.

WIDER IMPLICATIONS OF THESE FINDINGS

High PCNA expression attenuates endometrial adhesive capacity and decidualization in patients with RIF. These findings provide new insights into the potential mechanisms underlying the occurrence of implantation failure.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Natural Science Foundation of China (82101698), Shandong Provincial Natural Science Foundation (ZR2021MH012), and the Science and Technology Plan of Yantai (2023YD021 and 2022YD031). The authors have no conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Uterine fluid microRNAs in repeated implantation failure

Recurrent implantation failure (RIF) is a significant obstacle in assisted reproductive procedures, primarily because of compromised receptivity. As such, there is a need for a dependable and accurate clinical test to evaluate endometrial receptiveness, particularly during embryo transfer. MicroRNAs (miRNAs) have diverse functions in the processes of implantation and pregnancy. Dysregulation of miRNAs results in reproductive diseases such as recurrent implantation failure (RIF). The endometrium secretes several microRNAs (miRNAs) during the implantation period, which could potentially indicate whether the endometrium is suitable for in vitro fertilization (IVF). The goal of this review is to examine endometrial miRNAs as noninvasive biomarkers that successfully predict endometrium receptivity in RIF.

Long noncoding RNA BMPR1B-AS1 stability regulated by IGF2BP2 affects the decidualization in endometriosis patients through the SMAD1/5/9 pathway

Endometriosis (EMs)-related infertility commonly has decreased endometrial receptivity and normal decidualization is the basis for establishing and maintaining endometrial receptivity. However, the potential molecular regulatory mechanisms of impaired endometrial decidualization in patients with EMs have not been fully clarified. We confirmed the existence of reduced endometrial receptivity in patients with EMs by scanning electron microscopy and quantitative real-time PCR. Here we identified an lncRNA, named BMPR1B-AS1, which is significantly downregulated in eutopic endometrium in EMs patients and plays an essential role in decidual formation. Furthermore, RNA pull-down, mass spectrometry, RNA immunoprecipitation, and rescue analyses revealed that BMPR1B-AS1 positively regulates decidual formation through interaction with the RNA-binding protein insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2). Downregulation of IGF2BP2 led to a decreased stability of BMPR1B-AS1 and inhibition of activation of the SMAD1/5/9 pathway, an inhibitory effect which diminished decidualization in human endometrial stromal cells (hESCs) decidualization. In conclusion, our identified a novel regulatory mechanism in which the IGF2BP2-BMPR1B-AS1-SMAD1/5/9 axis plays a key role in the regulation of decidualization, providing insights into the potential link between abnormal decidualization and infertility in patients with EMs, which will be of clinical significance for the management and treatment of infertility in patients with EMs.

An endometrial biomimetic extracellular matrix (ECM) for enhanced endometrial regeneration using hyaluronic acid hydrogel containing recombinant human type III collagen

Endometrial injury poses a significant challenge in tissue regeneration, with type III collagen (COL III) playing a pivotal role in maintaining endometrial integrity and facilitating repair. Our study explored the utility of recombinant human type III collagen (RHC) as an intervention for endometrial damage. To address the challenges associated with the inherent instability and rapid degradation of COL III in vivo, we developed an RHC-HA hydrogel by conjugating RHC with hyaluronic acid (HA), thus ensuring a more stable and sustained delivery. Our findings suggested that the RHC-HA hydrogel significantly promoted endometrial regeneration and restored fertility. The hydrogel facilitated prolonged retention of RHC in the uterus, leading to a substantial improvement in the repair process. The synergistic interaction between RHC and HA greatly enhances cell proliferation and adhesion, surpassing the efficacy of HA or RHC alone. Additionally, the RHC-HA hydrogel demonstrated notable anti-fibrotic effects, which are crucial for preventing abnormalities during endometrial healing. These findings suggested that the RHC-HA hydrogel presented a therapeutic strategy in the treatment of uterine endometrial injuries, which may improve female reproductive health.

Incorporation of Decidual Stromal Cells Derived Exosomes in Sodium Alginate Hydrogel as an Innovative Therapeutic Strategy for Advancing Endometrial Regeneration and Reinstating Fertility

Intrauterine adhesion (IUA) stands as a prevalent medical condition characterized by endometrial fibrosis and scar tissue formation within the uterine cavity, resulting in infertility and, in severe cases, recurrent miscarriages. Cell therapy, especially with stem cells, offers an alternative to surgery, but concerns about uncontrolled differentiation and tumorigenicity limit its use. Exosomes, more stable and immunogenicity-reduced than parent cells, have emerged as a promising avenue for IUA treatment. In this study, a novel approach has been proposed wherein exosomes originating from decidual stromal cells (DSCs) are encapsulated within sodium alginate hydrogel (SAH) scaffolds to repair endometrial damage and restore fertility in a mouse IUA model. Current results demonstrate that in situ injection of DSC-derived exosomes (DSC-exos)/SAH into the uterine cavity has the capability to induce uterine angiogenesis, initiate mesenchymal-to-epithelial transformation (MET), facilitate collagen fiber remodeling and dissolution, promote endometrial regeneration, enhance endometrial receptivity, and contribute to the recovery of fertility. RNA sequencing and advanced bioinformatics analysis reveal miRNA enrichment in exosomes, potentially supporting endometrial repair. This finding elucidates how DSC-exos/SAH mechanistically fosters collagen ablation, endometrium regeneration, and fertility recovery, holding the potential to introduce a novel IUA treatment and offering invaluable insights into the realm of regenerative medicine.

Homeobox regulator Wilms Tumour 1 is displaced by androgen receptor at cis-regulatory elements in the endometrium of PCOS patients

Decidualisation, the process whereby endometrial stromal cells undergo morphological and functional transformation in preparation for trophoblast invasion, is often disrupted in women with polycystic ovary syndrome (PCOS) resulting in complications with pregnancy and/or infertility. The transcription factor Wilms tumour suppressor 1 (WT1) is a key regulator of the decidualization process, which is reduced in patients with PCOS, a complex condition characterized by increased expression of androgen receptor in endometrial cells and high presence of circulating androgens. Using genome-wide chromatin immunoprecipitation approaches on primary human endometrial stromal cells, we identify key genes regulated by WT1 during decidualization, including homeobox transcription factors which are important for regulating cell differentiation. Furthermore, we found that AR in PCOS patients binds to the same DNA regions as WT1 in samples from healthy endometrium, suggesting dysregulation of genes important to decidualisation pathways in PCOS endometrium due to competitive binding between WT1 and AR. Integrating RNA-seq and H3K4me3 and H3K27ac ChIP-seq metadata with our WT1/AR data, we identified a number of key genes involved in immune response and angiogenesis pathways that are dysregulated in PCOS patients. This is likely due to epigenetic alterations at distal enhancer regions allowing AR to recruit cofactors such as MAGEA11, and demonstrates the consequences of AR disruption of WT1 in PCOS endometrium.

A comprehensive review of lncRNA CRNDE in cancer progression and pathology, with a specific glance at the epithelial-mesenchymal transition (EMT) process

It has been suggested that the long non-coding RNAs (lncRNAs), such as colorectal neoplasia differentially expressed (CRNDE), may contribute to the formation of human cancer. It is yet unknown, though, what therapeutic significance CRNDE expression has for different forms of cancer. CRNDE has recently been proposed as a possible diagnostic biomarker and prognostic pred for excellent specificity and sensitivity in cancer tissues and plasma. To provide the groundwork for potential future therapeutic uses of CRNDE, we briefly overview its biological action and related cancer-related pathways. Next, we mainly address the impact of CRNDE on the epithelial-mesenchymal transition (EMT). The epithelial-mesenchymal transition, or EMT, is an essential biological mechanism involved in the spread of cancer.

Lithium chloride promotes mesenchymal-epithelial transition in murine cutaneous wound healing via inhibiting CXCL9 and IGF2

Cutaneous wound healing is a challenge in plastic and reconstructive surgery. In theory, cells undergoing mesenchymal transition will achieve re-epithelialization through mesenchymal-epithelial transition at the end of wound healing. But in fact, some pathological stimuli will inhibit this biological process and result in scar formation. If mesenchymal-epithelial transition can be activated at the corresponding stage, the ideal wound healing may be accomplished. Two in vivo skin defect mouse models and dermal-derived mesenchymal cells were used to evaluate the effect of lithium chloride in wound healing. The mesenchymal-epithelial transition was detected by immunohistochemistry staining. In vivo, differentially expressed genes were analysed by transcriptome analyses and the subsequent testing was carried out. We found that lithium chloride could promote murine cutaneous wound healing and facilitate mesenchymal-epithelial transition in vivo and in vitro. In lithium chloride group, scar area was smaller and the collagen fibres are also orderly arranged. The genes related to mesenchyme were downregulated and epithelial mark genes were activated after intervention. Moreover, transcriptome analyses suggested that this effect might be related to the inhibition of CXCL9 and IGF2, subsequent assays demonstrated it. Lithium chloride can promote mesenchymal-epithelial transition via downregulating CXCL9 and IGF2 in murine cutaneous wound healing, the expression of IGF2 is regulated by β-catenin. It may be a potential promising therapeutic drug for alleviating postoperative scar and promoting re-epithelialization in future.

In vivo effect of vaginal seminal plasma application on the human endometrial transcriptome: a randomized controlled trial

Studies in humans and animals suggest that seminal plasma, the acellular seminal fluid component, stimulates the endometrium to promote immune tolerance and facilitate implantation. We designed a randomized, double-blinded, placebo-controlled trial to investigate changes in the endometrial transcriptomic profile after vaginal application of seminal plasma. The study participants were randomized into two groups. Five women received a vaginal application of seminal plasma, and four received a placebo application with saline solution. The application was performed 2 days after HCG-triggered ovulation in an unstimulated cycle. After 5-8 days, an endometrial biopsy was collected to analyze differences in the endometrial transcriptomic profile using microarray analyses. A differential gene expression analysis and a gene set analysis were performed. The gene set enrichment analysis showed a positive enrichment of pathways associated with the immune response, cell viability, proliferation, and cellular movement. Moreover, pathways involved in implantation, embryo development, oocyte maturation, and angiogenesis were positively enriched. The differential gene expression analysis, after adjusting for multiple testing, showed no significantly differentially expressed genes between the two groups. A comparative analysis was also performed with similar studies conducted in other animals or in vitro using human endometrial cells. The comparative analysis showed that the effect of seminal plasma effect on the endometrium is similar in pigs, mice, and in vitro human endometrial cells. The present study provides evidence that seminal plasma might impact the endometrium during the implantation window, with potential to affect endometrial receptivity and embryo development.

Multiomics insights into the female reproductive aging

The human female reproductive lifespan significantly diminishes with age, leading to decreased fertility, reduced fertility quality and endocrine function disorders. While many aspects of aging in general have been extensively documented, the precise mechanisms governing programmed aging in the female reproductive system remain elusive. Recent advancements in omics technologies and computational capabilities have facilitated the emergence of multiomics deep phenotyping. Through the application and refinement of various high-throughput omics methods, a substantial volume of omics data has been generated, deepening our comprehension of the pathogenesis and molecular underpinnings of reproductive aging. This review highlights current and emerging multiomics approaches for investigating female reproductive aging, encompassing genomics, epigenomics, transcriptomics, proteomics, metabolomics, and microbiomics. We elucidate their influence on fundamental cell biology and translational research in the context of reproductive aging, address the limitations and current challenges associated with multiomics studies, and offer a glimpse into future prospects.

CD24+ decidual stromal cells: a novel heterogeneous population with impaired regulatory T cell induction and potential association with recurrent miscarriage

OBJECTIVE

To explore the heterogeneity of CD24+ decidual stromal cells (DSCs) in patients with recurrent miscarriages (RMs).

DESIGN

We have discerned that the expression of CD24 serves to differentiate two stable and functionally distinct lineages of DSCs. The heterogeneity of CD24+ DSCs has been scrutinized, encompassing variances in stromal markers, transcriptional profiles, metabolic activity, and immune regulation.

SETTING

Department of Reproductive Immunology, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University; Shanghai Institute of Immunity and Infection, Chinese Academy of Science.

PATIENTS

A total of 129 early decidual samples were obtained, comprising 36 from healthy donors and 93 from patients with RMs. Blood samples were collected before the surgical procedure. Paraffin-embedded segments from 20 decidual samples of patients with RMs were obtained.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

The flow cytometry was used to quantify the expression of CD24+ DSCs in both healthy donors and patients with RMs, although it also evaluated the cellular heterogeneity. To ascertain the transcriptomic profiles of CD24+ DSCs by reanalyzing our single-cell transcriptomic data. Additionally, to measure the metabolomic activity of CD24+ DSCs from patients with RMs, ultraperformance liquid chromatography-mass spectrometry was employed. Through the implementation of a coculture system, we unraveled the role of CD24+ DSCs in immune regulation.

RESULTS

Patients with RMs exhibit a notable enrichment of CD24+ DSCs, revealing a pronounced heterogeneity characterized by variations in stromal markers and transcriptional profiles. The heightened enrichment of CD24+ DSCs may play a pivotal role in triggering decidual inflammation and dysfunction in decidualization. Furthermore, CD24+ DSCs showed diverse metabolic activities and impeded the induction of naïve CD4+ T cells into regulatory T cells through the abundant secretion of 3-hydroxyisovaleric acid. Finally, our investigations have revealed that intraperitoneal administration of 3-hydroxyisovaleric acid in mouse models can elevate the risk of RM.

CONCLUSION

We have successfully identified a disease-associated subset of CD24+ decidual stromal cells that could potentially contribute to the development of RM through the impairment of decidual immune tolerance. Targeting these specific CD24+ DSCs might hold promising prospects for therapeutic interventions in the clinical management of RM.

Hyperinsulinemia impairs decidualization via AKT-NR4A1 signaling: new insight into polycystic ovary syndrome (PCOS)-related infertility

BACKGROUND

Investigating the underlying molecular mechanisms responsible for endometrial dysfunction in women with PCOS is essential, particularly focusing on the role of hyperinsulinemia.

METHODS

We explored the role of insulin in the decidualization process using a synthetic decidualization assay. To dissect the effects of PI3K/AKT-NR4A signaling, we employed small interfering RNAs (siRNAs) targeting the NR4A genes and inhibitors of the PI3K/AKT pathway. We also investigated the disruption of AKT-NR4A1 signaling in the endometrium of PCOS female rats induced with dehydroepiandrosterone (DHEA). Quantitative real-time PCR (qRT-PCR) and Western blot (WB) analyses were utilized to evaluate gene expression regulation.

RESULTS

Insulin was found to suppress the expression of decidualization markers in human endometrial stromal cells (hESC) in a dose-dependent manner, concurrently triggering an inappropriate activation of the PI3K/AKT pathway. Members of the NR4A family, as downstream effectors in the PI3K/AKT pathway, were implicated in the insulin-induced disruptions during the decidualization process. Moreover, the endometrium of PCOS models showed significantly elevated levels of phosphorylated (Ser473) AKT, with a corresponding reduction in Nr4a1 protein.

CONCLUSIONS

Our research demonstrates that insulin negatively regulates decidualization in hESC via the PI3K/AKT-NR4A pathway. In vivo analysis revealed a significant dysregulation of the AKT-NR4A1 pathway in the endometrium of PCOS rats. These findings offer novel insights into the pathogenesis of infertility and endometrial disorders associated with hyperinsulinemia in PCOS.

The involvement of RNA N6-methyladenosine and histone methylation modification in decidualization and endometriosis-associated infertility

Defective decidualization of endometrial stromal cells (ESCs) in endometriosis (EM) patients leads to inadequate endometrial receptivity and EM-associated infertility. Hypoxia is an inevitable pathological process of EM and participates in deficient decidualization of the eutopic secretory endometrium. Enhancer of zeste homology 2 (EZH2) is a methyltransferase which catalyses H3K27Me3, leading to decreased expression levels of target genes. Although EZH2 expression is low under normal decidualization, it is abundantly increased in the eutopic secretory endometrium of EM and is induced by hypoxia. Chromatin immunoprecipitation-PCR results revealed that decidua marker IGFBP1 is a direct target of EZH2, partially explaining the increased levels of histone methylation modification in defected decidualization of EM. To mechanism controlling this, we examined the effects of hypoxia on EZH2 and decidualization. EZH2 mRNA showed decreased m6 A modification and increased expression levels under hypoxia and decidualization combined treatment. Increased EZH2 expression was due to the increased expression of m6 A demethylase ALKBH5 and decreased expression of the m6 A reader protein YTHDF2. YTHDF2 directly bind to the m6 A modification site of EZH2 to promote EZH2 mRNA degradation in ESCs. Moreover, selective Ezh2 depletion in mouse ESCs increased endometrial receptivity and improved mouse fertility by up-regulating decidua marker IGFBP1 expression. This is the first report showing that YTHDF2 can act as a m6 A reader to promote decidualization by decreasing the stability of EZH2 mRNA and further increasing the expression of IGFBP1 in ESCs. Taken together, our findings highlight the critical role of EZH2/H3K27Me3 in decidualization and reveal a novel epigenetic mechanism by which hypoxia can suppress EM decidualization by decreasing the m6 A modification of EZH2 mRNA.

Jiawei Shoutai Pill promotes decidualization by regulating the SGK1/ENaC pathway in recurrent spontaneous abortion

ETHNOPHARMACOLOGICAL RELEVANCE

Jiawei Shoutai Pill (JWSTW) is a traditional herbal formula for recurrent spontaneous abortion (RSA). Although JWSTW significantly improves the clinical symptoms of RSA patients, its molecular mechanism remains unclear.

AIM OF STUDY

This study evaluated the expression and function of the serum/glucocorticoid regulated kinase 1/epithelial sodium channel (SGK1/ENaC) pathway and decidualization level in RSA patients and mice. It also investigated the therapeutic effects and potential mechanisms of JWSTW.

MATERIALS AND METHODS

30 early RSA patients and 30 normal pregnant women undergoing induced abortion during the same period were included in the study. Decidual tissues were collected, and HE staining, immunohistochemistry, Western blot, and RT-PCR were used to detect protein and mRNA expression levels of SGK1, ENaC-a, estrogen Rreceptor β (ERβ), and progesterone receptor (PR) in patients' decidual tissues. Protein expression levels of prolactin receptor (PRLR) and insulin-like growth factor binding protein 1 (IGFBP-1) were also detected. A classical RSA mouse model was constructed, and the mice were randomly divided into four groups: normal, model, dydrogesterone (DQYT) (0.33 g/kg/d), and JWSTW (1.66 g/kg/d). The normal and model groups received the same volume of distilled water by gavage for 8 and 14 days after pregnancy. On the 14th day of pregnancy, the embryonic loss rate of each group, the number of offspring born to naturally delivered mice, and the protein or mRNA expression levels of key factors of the SGK1/ENaC pathway (SGK1, ENaC-a, ERβ, and PR), decidual proliferation marker (Ki67), mesenchymal-epithelial transition (E-cadherin and Vimentin), and decidualization markers (PRLR and IGFBP-1) in mouse decidual tissue on the eighth day of pregnancy were observed.

RESULTS

The decidual tissue structure of RSA patients was abnormal. Immunohistochemical analysis revealed significantly reduced positive expression of SGK1, ENaC-a, ERβ, and PR proteins in the decidual tissue of RSA patients (P < 0.001). Western blot and RT-PCR analyses demonstrated significantly decreased protein and mRNA expression of SGK1, ENaC-a, ERβ, and PR in the decidual tissue of RSA patients (all P < 0.05). Additionally, protein expression of PRLR and IGFBP-1 was significantly reduced (both P < 0.001). The RSA mouse model exhibited a significant increase in embryo loss rate and decreased litter size (both P < 0.001). Treatment with DQYT and JWSTW rescued the embryo loss rate and litter size to varying extents (all P < 0.05). The protein or mRNA expression levels of SGK1, ENaC-a, ERβ, PR, Ki67, E-cadherin, vimentin, PRLR, and IGFBP-1 in RSA mice were improved to different degrees after treatment with DQYT and JWSTW (all P < 0.05).

CONCLUSIONS

Abnormal SGK1/ENaC signaling pathway regulation is closely associated with early endometrial damage in RSA patients. JWSTW promotes endometrial proliferation and mesenchymal-epithelial transition through the SGK1/ENaC signaling pathway, improving endometrial shedding. Consequently, JWSTW is a potential treatment for RSA.

IGF2BP2 regulates the proliferation and migration of endometrial stromal cells through the PI3K/AKT/mTOR signaling pathway in Hu sheep

Insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2), a significant member of the conserved RNA-binding protein family, plays various roles in numerous physiological and pathological processes. However, the specific function of IGF2BP2 in regulating endometrial function in sheep remains largely unknown. In this study, we observed a significant upregulation in IGF2BP2 mRNA abundance in the endometrium during the luteal phase compared to the follicular phase in Hu sheep. The knockdown of IGF2BP2 resulted in accelerated cell proliferation and migration of Hu sheep endometrial stromal cells (ESCs). Moreover, RNA sequencing analysis revealed that genes with significantly altered expression in IGF2BP2 knockdown cells were predominantly enriched in endometrial receptivity-related signaling pathways, such as cytokine-cytokine receptor interaction, NOD-like receptor, PI3K-AKT, and JAK-STAT signaling pathway. Additionally, the knockdown of IGF2BP2 significantly increased the expression of matrix metalloprotein 9 (MMP9), vascular endothelial growth factor, and prolactin (PRL) in ESCs. The knockdown of IGF2BP2 was also observed to stimulate the PI3K/AKT/mTOR pathway by upregulating integrin β4 (ITGB4) expression. Notably, the downregulation of ITGB4 attenuates IGF2BP2 knockdown-induced facilitation of proliferation and migration of Hu sheep ESCs by inhibiting the PI3K/AKT/mTOR pathway. Collectively, these findings highlight the important role of IGF2BP2 in regulating endometrial function, particularly through the modulation of ESC proliferation and migration via the PI3K/AKT/mTOR pathway.

Sodium alginate hydrogel integrated with type III collagen and mesenchymal stem cell to promote endometrium regeneration and fertility restoration

A thinner endometrium has been linked to implantation failure, and various therapeutic strategies have been attempted to improve endometrial regeneration, including the use of mesenchymal stem cells (MSCs). However, low survival and retention rates of transplanted stem cells are main obstacles to efficient stem cell therapy in thin endometrium. Collagen type III is a key component of the extracellular matrix, plays a crucial role in promoting cell proliferation and differentiation, and has been identified as the major collagen expressed at the implantation site. Herein, composite alginate hydrogel containing recombinant type III collagen (rCo III) and umbilical cord mesenchymal stem cells are developed. rCo III serves as favorable bioactive molecule, displaying that rCo III administration promotes MSCs proliferation, stemness maintenance and migration. Moreover, rCo III administration enhances cell viability and migration of mouse endometrial stromal cells (ESCs). In a mouse model of thin endometrium, the Alg-rCo III hydrogel loaded with MSCs (MSC/Alg-rCo III) significantly induces endometrial regeneration and fertility enhancement in vivo. Further studies demonstrate that the MSC/Alg-rCo III hydrogel promoted endometrial function recovery partly by regulating mesenchymal-epithelial transition of ESCs. Taken together, the combination of Alg-rCo III hydrogel and MSCs has shown promising results in promoting endometrium regeneration and fertility restoration, and may provide new therapeutic options for endometrial disease.

Pan-cancer analysis reveals the prognostic gene CASR suppresses tumor progression and epithelial-mesenchymal transition in renal clear cell carcinoma

Calcium-sensing receptor (CASR), primarily found in the parathyroid gland and other tissues, plays a crucial role in sensing and regulating extracellular calcium, which was also aberrantly expressed in human tumors. Nevertheless, a comprehensive analysis of CASR in pan-cancer has yet to be conducted. To gain a better understanding of CASR in pan-cancer, data profiles on CASR cancers were collected from TCGA database. The expression level, clinical significance, prognostic value, and potential mechanisms of CASR in pan-cancer were analyzed via multiple public databases. The functional assays were conducted using human kidney renal clear cell carcinoma (KIRC) cell lines, clinical samples, and nude mice. Our research revealed that the abnormal expression of CASR was found in a variety of tumors. The expression and mutation of CASR were significantly associated with tumor prognosis and stage. Pathway analyses suggested that CASR was involved in the epithelial-mesenchymal transition (EMT) progress. Besides, CASR expression was correlated with immune inhibitory genes and immunotherapy in cancers. Particularly in KIRC, we established that CASR mRNA and protein levels were downregulated in clinical samples and cell lines. Moreover, a Cox regression analysis revealed that CASR was an independent prognostic factor in both TCGA-KIRC samples and clinical samples from our center. In vitro and in vivo experiments revealed that blocking CASR with lentivirus could suppress tumor growth and invasion, and EMT progress in KIRC cells. In summary, our study provides a comprehensive bioinformatic analysis of CASR in pan-cancer, offering deeper insights into its function and the EMT mechanism in KIRC, warranting further investigation.

Validation of the Sw71-spheroid model with primary trophoblast cells

PROBLEM

Human implantation is a limiting factor for the success of natural and IVF reproduction since about 60% of pregnancy losses occur in the peri-implantation period. The in vitro modeling of human implantation challenges the researchers in accurate recreation of the complex in vivo differentiation and function of human blastocyst in the peri-implantation period. In previous studies, we constructed Sw71-spheroid models, which like human blastocyst undergo compactization, attaches to the endometrial epithelium, invade, and migrate. The aim of this study was to validate the trophoblast Sw71-spheroid model with primary trophoblast cells, derived from healthy women in early pregnancy.

METHOD OF STUDY

We performed a direct comparison of Sw71-spheroid model with placenta-derived primary trophoblasts regarding their hybrid phenotype and HLA status, as well as the ability to generate spheroids able to migrate and invade. From the primary trophoblast cells, isolated by mild enzymatic treatment and Percoll gradient separation, were generated long-lived clones, which phenotype was assessed by FACS and immunocytochemistry.

RESULTS

Our results showed that cultured primary trophoblasts have the EVT phenotype (Vim+/CK7+/HLA-C+/HLA-G+), like Sw71 cells. In both 3D culture settings, we obtained stable, round-shaped, multilayered spheroids. Although constructed from the same number of cells, the primary trophoblast spheroids were smaller. The primary trophoblast spheroids migrate successfully, and in term of invasion are equally potent but less stable as compared to Sw71 spheroids.

CONCLUSIONS

The Sw71 cell line and cultured native trophoblast cells are interchangeable regarding their EVT phenotype (HLA-C+/HLA-G+/Vim+/CK7+). The blastocyst-like spheroids sourced by both types of cells differentiate in the same time frame and function similarly. We strongly advise the use of Sw71 spheroids as blastocyst surrogate for observation on trophectoderm differentiation and function during early human implantation.

HIF-1α is positively associated with endometrial receptivity by regulating PKM2

PURPOSE

Numerous advancements have been introduced into the field of assisted reproductive technology (ART) in the past four decades. Nonetheless, implantation failure is still a key limiting step for a successful pregnancy. Building of endometrial receptivity (ER) is essential for successful implantation. However, the fundamental biological processes and mechanisms of ER remain elusive. Our study investigates the function of hypoxia inducible factor-1α (HIF-1α) during ER establishment and shed lights on the novel molecular mechanism by which HIF-1α regulates ER-related gene expression network.

METHODS

Levels of HIF-1α, homeobox A10 (HOXA10), insulin-like growth factor-binding protein 1 (IGFBP1), pyruvate kinase M2 (PKM2), and lactate dehydrogenase A (LDHA) in endometrial tissues were measured via real-time PCR, immunoblotting and immunohistochemistry. The correlation between HIF-1α and HOXA10, IGFBP1, PKM2, LDHA were analyzed separately. Ishikawa cells were treated with vector HIF-1α, HIF-1α-siRNA, and PKM2-siRNA. After transfection, the levels of HOXA10, IGFBP1, LDHA, and PKM2 were measured via real-time PCR and immunoblotting, and the lactate concentrations and cell migration of Ishikawa cells were measured.

RESULTS

Levels of HIF-1α, IGFBP1, HOXA10, LDHA, and PKM2 were significantly decreased in recurrent implantation failure (RIF) patients and levels of HOXA10, IGFBP1, PKM2, and LDHA were correlated with HIF-1α in endometrium. Then in a cellular model established by HIF-1α vector and HIF-1α-siRNA, the expression of HOXA10, IGFBP1, LDHA, PKM2, and lactate concentrations were dramatically upregulated and downregulated. And the expression of HOXA10, and IGFBP1 were dramatically decreased by PKM2-siRNA.

CONCLUSIONS

HIF-1α plays a crucial role in the building of ER through regulating glycolysis.

miRNAs associated with endoplasmic reticulum stress and unfolded protein response during decidualization

RESEARCH QUESTION

Do microRNAs (miRNAs) play a role in regulating endoplasmic reticulum stress (ERS) and unfolded protein response (UPR) in decidualized cells and endometrium associated with reproductive failures?

DESIGN

Endometrial stromal cell line St-T1b was decidualized in vitro with 8-Br-cAMP over 5 days, or treated with the ERS inducer thapsigargin. Expression of ERS sensors, UPR markers and potential miRNA regulators was analysed by quantitative PCR. Endometrial biopsies from patients with recurrent pregnancy loss (RPL) and recurrent implantation failure (RIF) were investigated for the location of miRNA expression.

RESULTS

Decidualization of St-T1b cells resulted in increased expression of ERS sensors including ATF6α, PERK and IRE1α, and the UPR marker, CHOP. TXNIP, which serves as a link between the ERS pathway and inflammation, as well as inflammasome NLRP3 and interleukin 1β expression increased in decidualized cells. An in-silico analysis identified miR-17-5p, miR-21-5p and miR-193b-3p as miRNAs potentially involved in regulation of the ERS/UPR pathways and inflammation associated with embryo implantation. Their expression decreased significantly (P ≤ 0.0391) in non-decidualized cells in the presence of thapsigargin. Finally, expression of the selected miRNAs was localized by in-situ hybridization in stromal and glandular epithelial cells in endometrial samples from patients with RPL and RIF. Expression in stroma cells from patients with RPL was lower in comparison with stroma cells from patients with RIF.

CONCLUSIONS

Decidualization in St-T1b cells is accompanied by ERS/UPR processes, associated with an inflammatory response that is potentially influenced by miR-17-5p, miR-21-5p and miR-193b-3p. These miRNAs are expressed differentially in stromal cells from patients with RPL and RIF, indicating an alteration in regulation of the ERS/UPR pathways.

Spatiotemporal insight into early pregnancy governed by immune-featured stromal cells

Endometrial decidualization connecting embryo implantation and placentation is transient but essential for successful pregnancy, which, however, is not systematically investigated. Here, we use a scStereo-seq technology to spatially visualize and define the dynamic functional decidual hubs assembled by distinct immune, endothelial, trophoblast, and decidual stromal cells (DSCs) in early pregnant mice. We unravel the DSC transdifferentiation trajectory and surprisingly discover a dual-featured type of immune-featured DSCs (iDSCs). We find that immature DSCs attract immune cells and induce decidual angiogenesis at the mesenchymal-epithelial transition hub during decidualization initiation. iDSCs enable immune cell recruitment and suppression, govern vascularization, and promote cytolysis at immune cell assembling and vascular hubs, respectively, to establish decidual homeostasis at a later stage. Interestingly, dysfunctional and spatially disordered iDSCs cause abnormal accumulation of immune cells in the vascular hub, which disrupts decidual hub specification and eventually leads to pregnancy complications in DBA/2-mated CBA/J mice.

Oncogene-Induced Senescence Is a Crucial Antitumor Defense Mechanism of Human Endometrial Stromal Cells

Being the major cellular component of highly dynamic tissue, endometrial stromal cells (EnSCs) are exposed to cycles of proliferation upon hormonal stimulation, which might pose risks for the accumulation of mutations and malignization. However, endometrial stromal tumors are rare and uncommon. The present study uncovered defense mechanisms that might underlie the resistance of EnSCs against oncogenic transformation. All experiments were performed in vitro using the following methods: FACS, WB, RT-PCR, IF, molecular cloning, lentiviral transduction, and CRISPR/Cas9 genome editing. We revealed that the expression of the mutant HRASG12V leads to EnSC senescence. We experimentally confirmed the inability of HRASG12V-expressing EnSCs to bypass senescence and resume proliferation, even upon estrogen stimulation. At the molecular level, the induction of oncogene-induced senescence (OIS) was accompanied by activation of the MEK/ERK, PI3K/AKT, p53/p21WAF/CIP/Rb, and p38/p16INK4a/Rb pathways; however, inhibiting either pathway did not prevent cell cycle arrest. PTEN loss was established as an additional feature of HRASG12V-induced senescence in EnSCs. Using CRISPR-Cas9-mediated PTEN knockout, we identified PTEN loss-induced senescence as a reserve molecular mechanism to prevent the transformation of HRASG12V-expressing EnSCs. The present study highlights oncogene-induced senescence as an antitumor defense mechanism of EnSCs controlled by multiple backup molecular pathways.

Treatment strategies for intrauterine adhesion: focus on the exosomes and hydrogels

Intrauterine adhesion (IUA), also referred to as Asherman Syndrome (AS), results from uterine trauma in both pregnant and nonpregnant women. The IUA damages the endometrial bottom layer, causing partial or complete occlusion of the uterine cavity. This leads to irregular menstruation, infertility, or repeated abortions. Transcervical adhesion electroreception (TCRA) is frequently used to treat IUA, which greatly lowers the prevalence of adhesions and increases pregnancy rates. Although surgery aims to disentangle the adhesive tissue, it can exacerbate the development of IUA when the degree of adhesion is severer. Therefore, it is critical to develop innovative therapeutic approaches for the prevention of IUA. Endometrial fibrosis is the essence of IUA, and studies have found that the use of different types of mesenchymal stem cells (MSCs) can reduce the risk of endometrial fibrosis and increase the possibility of pregnancy. Recent research has suggested that exosomes derived from MSCs can overcome the limitations of MSCs, such as immunogenicity and tumorigenicity risks, thereby providing new directions for IUA treatment. Moreover, the hydrogel drug delivery system can significantly ameliorate the recurrence rate of adhesions and the intrauterine pregnancy rate of patients, and its potential mechanism in the treatment of IUA has also been studied. It has been shown that the combination of two or more therapeutic schemes has broader application prospects; therefore, this article reviews the pathophysiology of IUA and current treatment strategies, focusing on exosomes combined with hydrogels in the treatment of IUA. Although the use of exosomes and hydrogels has certain challenges in treating IUA, they still provide new promising directions in this field.

Detection of zeb1 Gene in Granulosa Cells in Women Undergoing IVF Treatment

BACKGROUND

ZEB1 plays a role in epithelial-to-mesenchymal transition and acts as a repressor of E-cadherin, TGF-β, and Wnt/β-catenin. Since ZEB1 protein is expressed in estrogen-responsive tissues, and expression of the gene in the normal ovary and endometrium is positively correlated with high estrogen levels, we performed a direct analysis of granulosa cell samples to determine whether there are any significant changes in zeb1 expression during folliculogenesis.

METHODS

ZEB1 expression levels were measured in the granulosa cells of 56 infertile women undergoing IVF treatment. RNA extraction from granulosa cells was performed along with reverse transcription quantitative polymerase chain reaction (RT-qPCR) with SYBR Green I to determine zeb1 gene expression levels. Statistical analysis was performed by using t-test, while possible correlations of the expression of ZEB1 protein with body mass index (BMI), age, number of oocytes, and oocyte maturation were investigated.

RESULTS

Zeb1 gene expression levels correlate significantly with body mass index (BMI) and age, but not with oocyte number and oocyte maturation stage. Obese women demonstrate a higher expression level of zeb1 gene compared to normal and overweight women. Moreover, zeb1 gene is overexpressed in women aged 35-40 years old and is under-expressed in women >40 years old.

CONCLUSIONS

ZEB1 expression should be further investigated as it may unveil new potential findings of the zeb1 gene's role in female fertility and its use as a biomarker in fertility workups.

The landscape of implantation and placentation: deciphering the function of dynamic RNA methylation at the maternal-fetal interface

The maternal-fetal interface is defined as the interface between maternal tissue and sections of the fetus in close contact. RNA methylation modifications are the most frequent kind of RNA alterations. It is effective throughout both normal and pathological implantation and placentation during pregnancy. By influencing early embryo development, embryo implantation, endometrium receptivity, immune microenvironment, as well as some implantation and placentation-related disorders like miscarriage and preeclampsia, it is essential for the establishment of the maternal-fetal interface. Our review focuses on the role of dynamic RNA methylation at the maternal-fetal interface, which has received little attention thus far. It has given the mechanistic underpinnings for both normal and abnormal implantation and placentation and could eventually provide an entirely novel approach to treating related complications.

Recurrent Implantation Failure: Bioinformatic Discovery of Biomarkers and Identification of Metabolic Subtypes

Recurrent implantation failure (RIF) is a challenging scenario from different standpoints. This study aimed to investigate its correlation with the endometrial metabolic characteristics. Transcriptomics data of 70 RIF and 99 normal endometrium tissues were retrieved from the Gene Expression Omnibus database. Common differentially expressed metabolism-related genes were extracted and various enrichment analyses were applied. Then, RIF was classified using a consensus clustering approach. Three machine learning methods were employed for screening key genes, and they were validated through the RT-qPCR experiment in the endometrium of 10 RIF and 10 healthy individuals. Receiver operator characteristic (ROC) curves were generated and validated by 20 RIF and 20 healthy individuals from Peking University People's Hospital. We uncovered 109 RIF-related metabolic genes and proposed a novel two-subtype RIF classification according to their metabolic features. Eight characteristic genes (SRD5A1, POLR3E, PPA2, PAPSS1, PRUNE, CA12, PDE6D, and RBKS) were identified, and the area under curve (AUC) was 0.902 and the external validated AUC was 0.867. Higher immune cell infiltration levels were found in RIF patients and a metabolism-related regulatory network was constructed. Our work has explored the metabolic and immune characteristics of RIF, which paves a new road to future investigation of the related pathogenic mechanisms.

Global endometrial DNA methylation analysis reveals insights into mQTL regulation and associated endometriosis disease risk and endometrial function

Endometriosis is a leading cause of pain and infertility affecting millions of women globally. Herein, we characterize variation in DNA methylation (DNAm) and its association with menstrual cycle phase, endometriosis, and genetic variants through analysis of genotype data and methylation in endometrial samples from 984 deeply-phenotyped participants. We estimate that 15.4% of the variation in endometriosis is captured by DNAm and identify significant differences in DNAm profiles associated with stage III/IV endometriosis, endometriosis sub-phenotypes and menstrual cycle phase, including opening of the window for embryo implantation. Menstrual cycle phase was a major source of DNAm variation suggesting cellular and hormonally-driven changes across the cycle can regulate genes and pathways responsible for endometrial physiology and function. DNAm quantitative trait locus (mQTL) analysis identified 118,185 independent cis-mQTLs including 51 associated with risk of endometriosis, highlighting candidate genes contributing to disease risk. Our work provides functional evidence for epigenetic targets contributing to endometriosis risk and pathogenesis. Data generated serve as a valuable resource for understanding tissue-specific effects of methylation on endometrial biology in health and disease.