Impaired decidualization of human endometrial stromal cells from women with adenomyosis†

The effect and mechanism of low-molecular-weight heparin on the decidualization of stromal cells in early pregnancy

OBJECTIVE

This study aimed to analyze the effect of low-molecular-weight heparin (LMWH) on the decidualization of stromal cells in early pregnancy and explore the effect of LMWH on pregnancy outcomes.

METHODS

Recurrent spontaneous abortion (RSA) mouse model (CBA/J × DBA/2) and normal pregnant mouse model (CBA/J × BALB/c) were established. The female mice were checked for a mucus plug twice daily to identify a potential pregnancy. When a mucus plug was found, conception was considered to have occurred 12 h previously. The pregnant mice were divided randomly into a normal pregnancy control group, an RSA model group, and an RSA + LMWH experimental group (n = 10 mice in each group). Halfway through the 12th day of pregnancy, the embryonic loss of the mice was observed; a real-time quantitative polymerase chain reaction was used to detect the messenger ribonucleic acid (mRNA) expressions of prolactin (PRL) and insulin-like growth factor-binding protein 1 (IGFBP1) in the decidua of the mice. Additionally, the decidual tissues of patients with RSA and those of normal women in early pregnancy who required artificial abortion were collected and divided into an RSA group and a control group. Decidual stromal cells were isolated and cultured to compare cell proliferation between the two groups, and cellular migration and invasion were detected by membrane stromal cells. Western blotting was used to detect the protein expressions of proliferating cell nuclear antigen (PCNA), cyclin D1, matrix metalloproteinase- (MMP) 2, and MMP-7 in stromal cells treated with LMWH.

RESULTS

Compared with the RSA group, LMWH significantly reduced the pregnancy loss rate in the RSA mice (p < 0.05). Compared with the RSA group, the LMWH + RSA group had significantly higher expression levels of PRL and IGFBP1 mRNA (p < 0.01). LMWH promoted the proliferation, migration, and invasion of human decidual stromal cells; compared with the control group, the expression levels of MMP-2, MMP-7, cyclin D1, and PCNA proteins in the decidual stromal cells of the LMWH group increased (p < 0.05).

CONCLUSIONS

The use of LMWH can improve pregnancy outcomes by enhancing the proliferation and migration of stromal cells in early pregnancy and the decidualization of stromal cells.

Establishment of an immortalized cell line derived from human adenomyosis ectopic lesions

Because adenomyosis (AM) ectopic primary cells are hard to come by, have a short lifespan, and the characteristics that alter over time, their utility in AM research is constrained. This study aimed to establish a line of immortalized human adenomyosis ectopic cell (ihAMEC) to change this situation. Primary cells were obtained from AM ectopic lesion tissue and then infected with Simian Vacuolating Virus 40 Tag (SV40 T) lentivirus and screened to establish immortalized cells. We verified the main features and found that the ihAMEC could be cultured for more than 50 generations and the proliferation ability of ihAMEC was more active than that of primary cells. The cytoskeleton and cell types of ihAMEC were similar to primary cells and maintained a normal karyotype. The expression of epithelial-mesenchymal transition (EMT) markers, estrogen-metabolizing proteins, and estrogen/progesterone receptors in ihAMEC was similar to the expression seen in primary cells. In addition, the response of ihAMEC under estrogen treatment and Lipopolysaccharide intervention is similar to primary cells. The clonogenic ability of ihAMEC was lower than tumor cells and did not form tumors in tumorigenicity assays. Thus, ihAMEC can be used as in vitro cellular model for pathogenesis and drug development studies regarding AM.

Reduced fertility in an adenomyosis mouse model is associated with an altered immune profile in the uterus during the implantation period

STUDY QUESTION

Does a reduction in fertility and/or systemic immune cell change occur during the early implantation period in a mouse model of adenomyosis?

SUMMARY ANSWER

A reduction in fertility was observed in mice with adenomyosis, coinciding with local and systemic immune changes observed during the implantation period.

WHAT IS KNOWN ALREADY

Adenomyosis is a pathology responsible for impaired fertility in humans, with a still unclear pathophysiology. One hypothesis is that changes in immune cells observed in adenomyosis-affected uteri may alter fertility, notably the physiological immune environment necessary for successful implantation and a healthy pregnancy.

STUDY DESIGN, SIZE, DURATION

Randomly selected CD-1 female neonatal pups were orally dosed by administration of tamoxifen to induce adenomyosis (TAM group), while others received solvent only (control group). From 6 weeks of life, CD-1 mice of both groups were mated to study impaired fertility and related local and/or systemic immune cell changes during the early implantation period.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

To evaluate fertility and pregnancy outcomes, ultrasound imaging was performed at E (embryonic day) 7.5 and E11.5 to count the number of gestational sacs and the number of resorptions in eight mice of the TAM group and 16 mice of the control group. The mice were sacrificed at E18.5, and morphometric, functional (quantitative reverse transcription PCR; RT-qPCR), and histological analyses were performed on the placentas. To identify local and/or systemic immune changes during the early implantation period, 8 mice of the TAM group and 12 mice of the control group were sacrificed at E4.5. Uterine horns and spleens were collected for flow cytometry and RT-qPCR analyses to study the immune cell populations. To investigate the profile of the cytokines secreted during the early implantation period at the systemic level, supernatants from stimulated spleen cells were analyzed by multiplex immunoassay analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

By ultrasound imaging, we observed a lower number of implantation sites (P < 0.005) and a higher number of resorptions (P < 0.001) in the TAM group, leading to smaller litters (average number of fetuses per litter: 1.00 [0.00; 5.25] in the TAM group versus 12.00 [9.50; 13.75] in the control group (P < 0.001). Histological and morphometric analyses of the placentas at E18.5 showed a higher junctional/labyrinthine area ratio in the TAM group (P = 0.005). The expression levels of genes that play a role in vascularization and placental growth (Vegf (P < 0.001), Plgf (P < 0.005), Pecam (P < 0.0001), and Igf2 (P = 0.002)) were reduced in the TAM group. In the TAM group, the percentages of macrophages, natural killer (NK) cells, and dendritic cells (DC) were significantly decreased in the uterus around the implantation period. However, the number of M1 macrophages was increased. Both macrophages and DC had an increased activation profile (higher expression of MCHII, P = 0.012; CD80, P = 0.015; CCR7, P = 0.043 for macrophages, and higher expression of CD206, P = 0.018; CXCR4, P = 0.010; CCR7, P = 0.006, MCHII, P = 0.010; and CD80, P = 0.012 for DC). In spleen, an increase in the activation of macrophages (CCR7, P = 0.002; MCHII, P = 0.001; and CD80, P = 0.034) and DC was observed in the TAM group (CCR7, P = 0.001; MCHII, P = 0.001; Ly6C, P = 0.015). In the uteri and the spleen, we observed increased percentages of CD4+ T lymphocytes (P = 0.0237 and P = 0.0136, respectively) in the TAM group and, in the uteri, an increased number of regulatory T cells (P = 0.036) compared with the controls.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

This study is limited by the use of an animal model and the lack of intervention.

WIDER IMPLICATIONS OF THE FINDINGS

These data support involvement of innate and adaptive immune cells in the implantation failure and the increased rate of resorption observed in the mouse model of adenomyosis. This substantiates the need for additional research in this domain, with the goal of addressing fertility challenges in women affected by this condition.

STUDY FUNDING/COMPETING INTEREST(S)

None.

Estrogen Regulates Scribble Localization in Endometrial Epithelial Cells Through Acyl Protein Thioesterase (APT)-Mediated S-Palmitoylation in Adenomyosis

Despite its prevalence and the severity of symptoms, little is known about the pathogenesis and etiology of adenomyosis. In our previous study, Scribble localization has been found to be partially translocated to cytoplasm; however, its regulatory mechanism is known. In consideration of the important role of supraphysiologic estrogen production in the endometrium in the development of adenomyosis, we analyzed the effect and mechanism of estrogen on Scribble localization in vivo and in vitro. Firstly, we found Scribble translocation from the basolateral membrane to the cytoplasm was easily to be seen in women and mice with adenomyosis (68% vs 27%, 60% vs 10% separately). After treatment with the S-palmitoylation inhibitor 2-bromopalmitate for 48H, cytoplasmic enrichment of Scribble and the reduced level of palm-Scribble was observed by immunofluorescence, Western blot, and acyl-biotin exchange palmitoylation assay. High estrogen exposure could not only induce partially cytoplasmic translocation of Scribble but also decrease the expression level of palm-Scribble, which can be recovered by estrogen receptor inhibitor ICI182,780. Based on following experiments, we found that estrogen regulated Scribble localization by APT through S-palmitoylation of Scribble protein. At last, IHC was performed to verify the expression of APT1 and APT2 in human clinical tissue specimens and found that they were all increased dramatically. Furthermore, positive correlations were found between APT1 or APT2 and aromatase P450. Therefore, our research may provide a new understanding of the pathogenesis of adenomyosis.

Current perspectives on endometrial receptivity: A comprehensive overview of etiology and treatment

Recurrent implantation failure (RIF) remains a challenging problem in assisted reproductive technology (ART). Further insights into uterine abnormalities that can disturb embryo implantation should be obtained. This review provides an overview of the effects of organic and non-organic uterine disorders on endometrial receptivity. The results suggest that various uterine pathologies can lead to defective embryo implantation via multiple mechanisms. In particular, uterine adenomyosis dysregulates molecular and cellular interactions that are vital for successful embryo implantation with a background of chronic inflammation, which may be alleviated by pretreatment with a gonadotropin-releasing hormone agonist. Uterine myomas can cause endometrial deformation and adverse alterations in uterine contractility. Nonetheless, the effectiveness of myomectomy remains debated, and endometrial polyp removal may be considered, particularly in patients with RIF. Chronic endometritis abrogates the appropriate uterine immunological environment critical for embryo implantation. Abnormal endometrial microbiota have been suggested to influence endometrial receptivity; however, supporting evidence is currently scarce. Platelet-rich plasma therapy may be a potential treatment for thin endometria; nevertheless, further validation is required. Endometrial receptivity analysis can detect dysregulation of the window of implantation, and new non-invasive methods for predicting endometrial receptivity have recently been proposed. However, numerous issues still need to be fully clarified. Further clinical and basic studies are necessary to investigate the pathophysiology of defective endometrial receptivity and identify optimal treatments for patients undergoing ART, especially those with RIF.

Molecular Targets for Nonhormonal Treatment Based on a Multistep Process of Adenomyosis Development

Adenomyosis is an estrogen-dependent gynecologic disease characterized by the presence of endometrial tissue within the myometrium. Adenomyosis presents with abnormal uterine bleeding, pelvic pains, and infertility. This review aimed to investigate the major estrogen downstream effectors involved in the process of adenomyosis development and their potential use for nonhormonal treatment. A literature search was performed for preclinical and clinical studies published between January 2010 and November 2021 in the PubMed and Google Scholar databases using a combination of specific terms. Adenomyosis presents with a wide spectrum of clinical manifestations from asymptomatic to severe through a complex process involving a series of molecular changes associated with inflammation, invasion, angiogenesis, and fibrosis. Adenomyosis may develop through a multistep process, including the acquisition of (epi)genetic mutations, tissue injury caused at the endometrial-myometrial interface, inside-to-outside invasion (from the endometrial side into the uterine wall), or outside-to-inside invasion (from the serosal side into the uterine wall), and epithelial-mesenchymal transition, tissue repair or remodeling in the myometrium. These processes can be regulated by increased estrogen biosynthesis and progesterone resistance. The expression of estrogen downstream effectors associated with persistent inflammation, fragile and more permeable vessel formation, and tissue injury and remodeling may be correlated with dysmenorrhea, heavy menstrual bleeding, and infertility, respectively. Key estrogen downstream targets (e.g., WNT/β-catenin, transforming growth factor-β, and nuclear factor-κB) may serve as hub genes. We reviewed the molecular mechanisms underlying the development of adenomyosis and summarized potential nonhormonal therapies.

Endometrial Inflammation and Impaired Spontaneous Decidualization: Insights into the Pathogenesis of Adenomyosis

Adenomyosis is an estrogen-dependent gynecologic disease characterized by the myometrial invasion of the endometrial tissue. This review summarized the current understanding and recent findings on the pathophysiology of adenomyosis, focusing on repeated menstruation, persistent inflammation, and impaired spontaneous decidualization. A literature search was performed in the PubMed and Google Scholar databases from inception to 30 April 2022. Thirty-one full-text articles met the eligibility criteria. Repeated episodes of physiological events (i.e., endometrial shedding, damage, proliferation, differentiation, repair, and regeneration) during the menstrual cycle are associated with inflammation, angiogenesis, and immune processes. The decidualization process in humans is driven by the rise in progesterone levels, independently of pregnancy (i.e., spontaneous decidualization). Adenomyotic cells produce angiogenic and fibrogenic factors with the downregulation of decidualization-associated molecules. This decidualization dysfunction and persistent inflammation are closely related to the pathogenesis of adenomyosis. Recently, it has been found that the reproductive tract microbiota composition and function in women with adenomyosis differ from those without. An increase in opportunistic pathogens and a decrease in beneficial commensals may promote impaired defense mechanisms against inflammation and predispose women to uncontrolled endometrial inflammation. However, currently, there is no direct evidence that adenomyosis is linked to pre-existing inflammation and impaired spontaneous decidualization. Overall, persistent inflammation, impaired spontaneous decidualization, and microbiota dysbiosis (i.e., an imbalance in the composition and function of endometrial microbiota) may be involved in the pathophysiology of adenomyosis.

Adenomyosis and fertility: does adenomyosis impact fertility and does treatment improve outcomes

PURPOSE OF REVIEW

Adenomyosis has recently been associated with infertility. Relief of bleeding and pain has been demonstrated with medical and surgical therapy. Less is known about reproductive outcomes after treatment.

RECENT FINDINGS

Imaging findings during infertility evaluation can be suggestive of adenomyosis without pathologic evaluation. Among women with infertility undergoing assisted reproductive technologies (ART), adenomyosis is associated with lower live birth rates and clinical pregnancy rates. Treatment with gonadotropin releasing hormone (GnRH) modulators prior to frozen embryo transfer may increase the live birth rate and clinical pregnancy rate among women with adenomyosis. Pregnancy has been documented following image-guided adenomyosis ablation; however, the reproductive impact is not well established. Pregnancy following excisional procedures appears to be well tolerated, although may carry a higher risk of uterine rupture compared with pregnancy following myomectomy. It is not clear if ablative therapy or resection increases pregnancy rates.

SUMMARY

Adenomyosis is associated with lower embryo implantation rates and ongoing pregnancy rates. Adenomyotic changes in the uterus can be seen by ultrasound and MRI. GnRH modulators may be useful for women with adenomyosis undergoing ART. Additional prospective data is warranted to determine the optimal medical or surgical therapy for women with adenomyosis desiring conception.Video abstract Supplementary digital content, http://links.lww.com/COOG/A78.

Emerging Concepts in Innate Lymphoid Cells, Memory, and Reproduction

Members of the innate immune system, innate lymphoid cells (ILCs), encompass five major populations (Natural Killer (NK) cells, ILC1s, ILC2s, ILC3s, and lymphoid tissue inducer cells) whose functions include defense against pathogens, surveillance of tumorigenesis, and regulation of tissue homeostasis and remodeling. ILCs are present in the uterine environment of humans and mice and are dynamically regulated during the reproductive cycle and pregnancy. These cells have been repurposed to support pregnancy promoting maternal immune tolerance and placental development. To accomplish their tasks, immune cells employ several cellular and molecular mechanisms. They have the capacity to remember a previously encountered antigen and mount a more effective response to succeeding events. Memory responses are not an exclusive feature of the adaptive immune system, but also occur in innate immune cells. Innate immune memory has already been demonstrated in monocytes/macrophages, neutrophils, dendritic cells, and ILCs. A population of decidual NK cells characterized by elevated expression of NKG2C and LILRB1 as well as a distinctive transcriptional and epigenetic profile was found to expand during subsequent pregnancies in humans. These cells secrete high amounts of interferon-γ and vascular endothelial growth factor likely favoring placentation. Similarly, uterine ILC1s in mice upregulate CXCR6 and expand in second pregnancies. These data provide evidence on the development of immunological memory of pregnancy. In this article, the characteristics, functions, and localization of ILCs are reviewed, emphasizing available data on the uterine environment. Following, the concept of innate immune memory and its mechanisms, which include epigenetic changes and metabolic rewiring, are presented. Finally, the emerging role of innate immune memory on reproduction is discussed. Advances in the comprehension of ILC functions and innate immune memory may contribute to uncovering the immunological mechanisms underlying female fertility/infertility, placental development, and distinct outcomes in second pregnancies related to higher birth weight and lower incidence of complications.

Trophoblast Cell Subtypes and Dysfunction in the Placenta of Individuals with Preeclampsia Revealed by Single‑Cell RNA Sequencing

Trophoblasts, important functional cells in the placenta, play a critical role in maintaining placental function. The heterogeneity of trophoblasts has been reported, but little is known about the trophoblast subtypes and distinctive functions during preeclampsia (PE). In this study, we aimed to gain insight into the cell type-specific transcriptomic changes by performing unbiased single-cell RNA sequencing (scRNA-seq) of placental tissue samples, including those of patients diagnosed with PE and matched healthy controls. A total of 29,006 cells were identified in 11 cell types, including trophoblasts and immune cells, and the functions of the trophoblast subtypes in the PE group and the control group were also analyzed. As an important trophoblast subtype, extravillous trophoblasts (EVTs) were further divided into 4 subgroups, and their functions were preliminarily analyzed. We found that some biological processes related to pregnancy, hormone secretion and immunity changed in the PE group. We also identified and analyzed the regulatory network of transcription factors (TFs) identified in the EVTs, among which 3 modules were decreased in the PE group. Then, through in vitro cell experiments, we found that in one of the modules, CEBPB and GTF2B may be involved in EVT dysfunction in PE. In conclusion, our study showed the different transcriptional profiles and regulatory modules in trophoblasts between placentas in the control and PE groups at the single-cell level; these changes may be involved in the pathological process of PE, providing a new molecular theoretical basis for preeclamptic trophoblast dysfunction.

Constant Activation of STAT3 Contributes to the Development of Adenomyosis in Females

Adenomyosis is a benign uterine disease that causes dysmenorrhea, heavy menstrual bleeding, and infertility; however, its pathophysiology remains unclear. Since signal transducer and activator of transcription 3 (STAT3) is crucial for endometrial regeneration, we hypothesized that STAT3 participates in adenomyosis pathophysiology. To investigate the influence of STAT3 on adenomyosis development, this study was performed using a novel mouse model of adenomyosis and human specimens of eutopic endometria and adenomyosis lesions. We established a novel mouse model of adenomyosis by puncturing entire mouse uterine layers with a thin needle. Mouse eutopic and ectopic endometria showed a positive immunoreactivity for phosphorylated STAT3 (pSTAT3), the active form of STAT3. Decreased numbers of adenomyotic lesions and reduced expression of Cxcl1, Icam1, and Spp1, which are associated with immune cell chemotaxis and tissue regeneration, were observed in uterine Stat3-deficient mice compared with the controls. In humans, pSTAT3 was intensely expressed at both the eutopic endometrium and the adenomyotic lesions regardless of the menstrual cycle phases. Conversely, it was limitedly expressed in the eutopic endometrium during the menstrual and proliferative phases in women without adenomyosis. Our findings indicate that continuous STAT3 activation promotes adenomyosis development. STAT3 inhibition can be a promising treatment strategy in patients with adenomyosis.

Role of lncRNA TUG1 in Adenomyosis and its Regulatory Mechanism in Endometrial Epithelial Cell Functions

OBJECTIVE

Adenomyosis (AM) is a common gynecological disorder that can cause pelvic pain. The regulatory role of long noncoding RNAs (lncRNAs) in AM progression has been widely reported. This study investigated the effect and mechanism of lncRNA taurine-upregulated gene 1 (TUG1) on endometrial epithelial cells (EECs) in AM.

METHODS

Endometrial tissues of AM patients and controls were collected. A murine model of AM was established by tamoxifen induction. TUG1 expression in endometrial tissues of AM patients and mice was determined. In vivo, the effect of TUG1 on AM mice was measured through H&E staining, Masson's staining, uterine weight, and estradiol concentration. EECs isolated from AM patients were transfected with sh-TUG1. In vitro, the effect of TUG1 on the proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), and angiogenesis of EECs was evaluated by CCK8, colony formation, immunofluorescence, wound healing, and Transwell assays. The binding relationship among TUG1, E2F4, and KLF5 was confirmed using RNA immunoprecipitation and RNA pull-down assays. A function rescue experiment was designed to verify the effect of KLF5 on EECs.

RESULTS

TUG1 expression was elevated in AM mice and patients. Downregulation of TUG1 promoted the recovery of AM mice. Downregulation of TUG1 suppressed proliferation, migration, invasion, EMT, and angiogenesis of EECs. Mechanically, TUG1 suppressed KLF5 transcription by binding to E2F4. Downregulation of KLF5 reversed the inhibitory effect of TUG1 silencing on the functions of EECs.

CONCLUSION

TUG1 expression was elevated in AM, and TUG1 facilitated proliferation, migration, invasion, EMT, and angiogenesis of EECs via E2F4/KLF5, thereby aggravating AM.

Transcriptomics of receptive endometrium in women with sonographic features of adenomyosis

BACKGROUND

Women with uterine adenomyosis seeking assisted reproduction have been associated with compromised endometrial receptivity to embryo implantation. To understand the mechanisms involved in this process, we aimed to compare endometrial transcriptome profiles during the window of implantation (WOI) between women with and without adenomyosis.

METHODS

We obtained endometrial biopsies LH-timed to the WOI from women with sonographic features of adenomyosis (n=10) and controls (n=10). Isolated RNA samples were subjected to RNA sequencing (RNA-seq) by the Illumina NovaSeq 6000 platform and endometrial receptivity classification with a molecular tool for menstrual cycle phase dating (beREADY®, CCHT). The program language R and Bioconductor packages were applied to analyse RNA-seq data in the setting of the result of accurate endometrial dating. To suggest robust candidate pathways, the identified differentially expressed genes (DEGs) associated with the adenomyosis group in the receptive phase were further integrated with 151, 173 and 42 extracted genes from published studies that were related to endometrial receptivity in healthy uterus, endometriosis and adenomyosis, respectively. Enrichment analyses were performed using Cytoscape ClueGO and CluePedia apps.

RESULTS

Out of 20 endometrial samples, 2 were dated to the early receptive phase, 13 to the receptive phase and 5 to the late receptive phase. Comparison of the transcriptomics data from all 20 samples provided 909 DEGs (p<0.05; nonsignificant after adjusted p value) in the adenomyosis group but only 4 enriched pathways (Bonferroni p value < 0.05). The analysis of 13 samples only dated to the receptive phase provided suggestive 382 DEGs (p<0.05; nonsignificant after adjusted p value) in the adenomyosis group, leading to 33 enriched pathways (Bonferroni p value < 0.05). These included pathways were already associated with endometrial biology, such as "Expression of interferon (IFN)-induced genes" and "Response to IFN-alpha". Data integration revealed pathways indicating a unique effect of adenomyosis on endometrial molecular organization (e.g., "Expression of IFN-induced genes") and its interference with endometrial receptivity establishment (e.g., "Extracellular matrix organization" and "Tumour necrosis factor production").

CONCLUSIONS

Accurate endometrial dating and RNA-seq analysis resulted in the identification of altered response to IFN signalling as the most promising candidate of impaired uterine receptivity in adenomyosis.

Scribble downregulation in adenomyosis compromises endometrial stromal decidualization by decreasing FOXO1 expression

STUDY QUESTION

Does Scribble (SCRIB) contribute to aberrant decidualization of endometrial stromal cells (ESC) in adenomyosis?

SUMMARY ANSWER

SCRIB knockdown impairs decidualization of ESC by decreasing Fork-head box O1A (FOXO1) expression through the protein kinase B (AKT) and atypical protein kinase C (aPKC) activated pathways.

WHAT IS KNOWN ALREADY

Stromal SCRIB is required for primary decidual zone formation and pregnancy success in mice. In our previous studies, decidualization was dampened in ESC isolated from adenomyosis patients, yet the underlying molecular mechanisms remain elusive.

STUDY DESIGN, SIZE, DURATION

Eutopic endometrium tissue samples from diffuse adenomyosis and non-adenomyosis patients in proliferative, early-secretory and mid-secretory phase (n = 10 per phase for each group) were explored. In parallel, in vitro decidualization studies were carried out in ESC isolated from non-adenomyosis women (n = 8).

PARTICIPANTS/MATERIALS, SETTING, METHODS

The endometrial SCRIB expression was analyzed using immunohistochemistry staining and western blot. Quantitative RT-PCR (qRT-PCR), western blot and immunofluorescence staining were used to explore the expression of SCRIB in ESC during in vitro decidualization. siRNA-mediated SCRIB knockdown followed by decidual markers expression analysis, flow cytometry for cell cycle analysis and phalloidin staining for morphological analysis were performed to examine the function of SCRIB in ESC decidualization. RNA-sequencing was performed to examine the SCRIB-mediated transcriptional changes in decidualized ESC (DSC). Rescue experiments using an AKT inhibitor MK2206 and aPKC inhibitor NSC37044 were used to investigate the signaling pathways through which could mediate SCRIB-regulated FOXO1 protein expression and ESC decidualization.

MAIN RESULTS AND THE ROLE OF CHANCE

We found that the expression of SCRIB in the mid-secretory phase eutopic endometrial stroma of adenomyosis patients was significantly lower than that of non-adenomyosis. SCRIB knockdown reduced the expression of decidual markers, abrogated the epithelioid-like morphological changes, inhibited the mesenchymal-to-epithelial transitions process and promoted the cell cycle progression of ESC during in vitro decidualization. SCRIB knockdown-induced decidualization defects were attributed to a decrease in expression of transcription factor FOXO1, known to regulate decidualization. Furthermore, we found that SCRIB knockdown induced the aberrant activation of AKT and aPKC, which led to FOXO1 phosphorylation and degradation. Rescue assay confirmed that restoring the expression of FOXO1 effectively reversed the decidualization defects and cell cycle progression caused by SCRIB knockdown.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

In this study, it was demonstrated that SCRIB knockdown mediated the activation of AKT and aPKC, contributing to FOXO1 degradation and aberrant decidualization, however, the molecular link between AKT and aPKC signaling was not determined, and still requires further exploration.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings support the hypothesis that adenomyosis interferes with embryo implantation due to insufficient endometrial receptivity. Abnormal decidualization of the endometrial stroma may clarify the possible association between adenomyosis and infertility. Our findings may be clinically useful for counseling and treatment of infertile adenomyosis patients.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the National Natural Science Foundation of China (82001523 and 82171639). The authors have no conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Uterine Adenomyosis: From Disease Pathogenesis to a New Medical Approach Using GnRH Antagonists

Uterine adenomyosis is a common chronic disorder frequently encountered in reproductive-age women, causing heavy menstrual bleeding, intense pelvic pain, and infertility. Despite its high prevalence, its etiopathogenesis is not yet fully understood, so there are currently no specific drugs to treat the disease. A number of dysregulated mechanisms are believed to contribute to adenomyosis development and symptoms, including sex steroid signaling, endometrial proliferation and invasiveness, and aberrant immune response. Abnormal sex steroid signaling, particularly hyperestrogenism and subsequent progesterone resistance, are known to play a pivotal role in its pathogenesis, which is why various antiestrogenic agents have been used to manage adenomyosis-related symptoms. Among them, gonadotropin-releasing hormone (GnRH) antagonists are swiftly gaining ground, with recent studies reporting efficient lesion regression and symptom alleviation. The aim of the present review is to compile available information on the pathogenesis of adenomyosis, explore the etiology and mechanisms of hyperestrogenism, and discuss the potential of antiestrogenic therapies for treating the disease and improving patient quality of life.