Premature expression of the decidualization marker prolactin is associated with repeated implantation failure

JAZF1 safeguards human endometrial stromal cells survival and decidualization by repressing the transcription of G0S2

Decidualization of human endometrial stromal cells (hESCs) is essential for the maintenance of pregnancy, which depends on the fine-tuned regulation of hESCs survival, and its perturbation contributes to pregnancy loss. However, the underlying mechanisms responsible for functional deficits in decidua from recurrent spontaneous abortion (RSA) patients have not been elucidated. Here, we observed that JAZF1 was significantly downregulated in stromal cells from RSA decidua. JAZF1 depletion in hESCs resulted in defective decidualization and cell death through apoptosis. Further experiments uncovered G0S2 as a important driver of hESCs apoptosis and decidualization, whose transcription was repressed by JAZF1 via interaction with G0S2 activator Purβ. Moreover, the pattern of low JAZF1, high G0S2 and excessive apoptosis in decidua were consistently observed in RSA patients. Collectively, our findings demonstrate that JAZF1 governs hESCs survival and decidualization by repressing G0S2 transcription via restricting the activity of Purβ, and highlight the clinical implications of these mechanisms in the pathology of RSA.

Prolactin Relationship with Fertility and In Vitro Fertilization Outcomes-A Review of the Literature

Hyperprolactinemia is a known cause of amenorrhea and infertility. However, there is an increasing body of evidence suggesting that prolactin is involved in multiple physiological aspects of normal reproduction. Thus, the present paper aims to review the current literature regarding the relationship between serum prolactin level and in vitro fertilization (IVF)/intracytoplasmic sperm injection outcome and the role of dopamine agonists treatment in IVF success. Moreover, the mechanisms by which prolactin may exert its role in fertility and infertility were summarized. Although not all studies agree, the available evidence suggests that higher prolactin levels in follicular fluid are associated with increased oocytes competence, but also with positive effects on corpus luteum formation and survival, endometrial receptivity, blastocyst implantation potential and survival of low-motile sperm. Transient hyperprolactinemia found in IVF cycles was reported in most of the studies not to be related to IVF outcome, although a few reports suggested that it may be associated with higher implantation and pregnancy rates, and better-cumulated pregnancy outcomes. Administration of dopamine agonists for hyperprolactinemia preceding IVF treatment does not seem to negatively impact the IVF results, while treatment of transient hyperprolactinemia during IVF might be beneficial in terms of fertilization rates and conception rates. Due to limited available evidence, future studies are necessary to clarify the optimal level of circulating prolactin in patients performing IVF and the role of dopamine agonist treatment.

Immunology of Pregnancy and Systemic Consequences

Pregnancy is an immunological paradox, with renowned Nobel Prize winning transplantation biologist Sir Peter Brian Medawar being the first to introduce this concept back in 1953. This concept considers how the maternal immune system can tolerate the developing fetus, which is 50% antigenically foreign to the uterus. There have been significant advances in our understanding of the immune system in regulating fertility, pregnancy and in complications of these, and what was once considered a paradox can be seen as a highly evolved system. Indeed, the complexity of the maternal-fetal interface along with our ever-advancing knowledge of immune cells and mediators means that we have a better understanding of these interactions, with gaps still present.  This chapter will summarise the key aspects of the role of the immune system at each stage of pregnancy and highlight the recent advances in our knowledge.

Temporal changes in cyclinD-CDK4/CDK6 and cyclinE-CDK2 pathways: implications for the mechanism of deficient decidualization in an immune-based mouse model of unexplained recurrent spontaneous abortion

BACKGROUND

Deficient endometrial decidualization has been associated with URSA. However, the underlying mechanism is poorly understood. This study aimed to investigate the temporal cytokine changes and the involvement of CyclinD-CDK4/6 and CyclinE-CDK2 pathways in the regulation of the G1 phase of the cell cycle during decidualization in a murine model of URSA.

METHODS

Serum and decidual tissues of mice were collected from GD4 to GD8. The embryo resorption and abortion rates were observed on GD8 and the decidual tissue status was assessed. In addition, PRL, Cyclin D, CDK6, CDK4, Cyclin E, CDK2 expression in mice were measured.

RESULTS

URSA mice showed high embryo resorption rate and PRL, Cyclin D, Cyclin E CDK2, CDK4, CDK6 down-regulation during decidualization. The hyperactivated Cyclin D-CDK4/CDK6 and cyclin E/CDK2 pathways inhibit the decidualization process and leading to deficient decidualization.

CONCLUSION

Insufficient decidualization is an important mechanism of URSA. which is related to the decrease of Cyclin D、Cyclin E、 CDK2、CDK4 and CDK6 in decidualization process of URSA.

Increased expression of prokineticin 2 and its receptor in endometrium of recurrent implantation failure patients decreased the expression of MMP9 important for decidualization

BACKGROUND

Studies have shown that abnormalities in the decidualization process were closely related to recurrent implantation failure (RIF). Prokineticin 2 (PK2) is a secreted protein with angiogenic and tissue remodeling functions but its role in the endometrium is unknown.

METHODS

PK2 levels and its receptor PKR1 mRNA and protein levels in mid-secretory endometrium from normal and RIF women were examined by real-time PCR and western blotting, respectively. The effects of PK2 were evaluated by overexpressed PK2 in immortalized endometrial T-HESC cells using lentivirus vector and found different expression of Matrix metalloproteinase 9(MMP9) and lncRNA LUCAT1 by RNA-sequencing. The ability of PK2 to regulate LUCAT1 and MMP9 was verified in endometrial cells by real-time PCR and western blotting.

RESULTS

Using endometrial biopsies from normal and RIF patients, we found increased expression of PK2, together with its receptor PKR1 in RIF patients. We then overexpressed PK2 in immortalized endometrial T-HESC cells using lentivirus vector and found decreased expression of Matrix metalloproteinase 9(MMP9), and increased expression of lncRNA LUCAT1. We verified the ability of PK2 to stimulate LUCAT1 and decrease MMP9 in endometrial cells. We further demonstrated that increased expression of a long noncoding RNA LUCAT1 and decreased expression of MMP9 in endometrial biopsies of patients with RIF. Thus, we highlighted the important role of PK2 and its receptor PKR1 in decidualization and RIF.

CONCLUSION

Prokineticin 2 and its receptor are important in endometrium decidualization. PK2 may affect endometrial decidualization through the LUCAT1- MMP9 pathway, thereby affecting embryo implantation.

The Role of Decidual Subpopulations in Implantation, Menstruation and Miscarriage

In each menstrual cycle, the endometrium becomes receptive to embryo implantation while preparing for tissue breakdown and repair. Both pregnancy and menstruation are dependent on spontaneous decidualization of endometrial stromal cells, a progesterone-dependent process that follows rapid, oestrogen-dependent proliferation. During the implantation window, stromal cells mount an acute stress response, which leads to the emergence of functionally distinct decidual subsets, reflecting the level of replication stress incurred during the preceding proliferative phase. Progesterone-dependent, anti-inflammatory decidual cells (DeC) form a robust matrix that accommodates the conceptus whereas pro-inflammatory, progesterone-resistant stressed and senescent decidual cells (senDeC) control tissue remodelling and breakdown. To execute these functions, each decidual subset engages innate immune cells: DeC partner with uterine natural killer (uNK) cells to eliminate senDeC, while senDeC co-opt neutrophils and macrophages to assist with tissue breakdown and repair. Thus, successful transformation of cycling endometrium into the decidua of pregnancy not only requires continuous progesterone signalling but dominance of DeC over senDeC, aided by recruitment and differentiation of circulating NK cells and bone marrow-derived decidual progenitors. We discuss how the frequency of cycles resulting in imbalanced decidual subpopulations may determine the recurrence risk of miscarriage and highlight emerging therapeutic strategies.

The association of in vitro fertilization/intracytoplasmic sperm injection results with anxiety levels and stress biomarkers: An observational, case-control study✰

INTRODUCTION

Anxiety has been considered to exert a negative influence on fecundity. However, it remains unclear whether it is a cause or a consequence and whether it is associated with the treatment outcome. This observational case control study evaluated the levels of state anxiety and various stress biomarkers and assessed their association with in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes.

MATERIALS AND METHODS

We allocated 109 infertile nulliparous women aged 25-45 years in their first IVF/ICSI fresh treatment cycle into two groups according to the final outcome: group A (PTP = pregnancy-test positive, n = 49) and group B (PTN = pregnancy-test negative, n = 60). State anxiety levels were measured with the Spielberger Trait Anxiety Inventory (STAI) questionnaire (Marteau and Bekker modification) on the days of oocyte retrieval (OR) and embryo transfer (ET). Serum stress biomarkers (cortisol, adrenaline, noradrenaline, α-amylase, and prolactin) were measured at the same time points. Blood samples were collected at 9 am.

RESULTS

Most women in both groups showed comparable mild-to-moderate degrees of state anxiety on the days of OR and ET (p = 0.183 and p = 0.760, respectively). The stress biomarker measurements did not differ between the two groups, except for noradrenaline that was higher in group B (p = 0.015) and associated with significant cardiovascular changes.

DISCUSSION

Women in both groups showed comparable levels of state anxiety, which were unlikely to influence the chance of pregnancy. Noradrenaline levels were higher in the non-pregnant group, with significant cardiovascular changes. Other stress biomarkers did not reflect the different treatment outcomes between the groups.

Modelling the impact of decidual senescence on embryo implantation in human endometrial assembloids

Decidual remodelling of midluteal endometrium leads to a short implantation window after which the uterine mucosa either breaks down or is transformed into a robust matrix that accommodates the placenta throughout pregnancy. To gain insights into the underlying mechanisms, we established and characterized endometrial assembloids, consisting of gland-like organoids and primary stromal cells. Single-cell transcriptomics revealed that decidualized assembloids closely resemble midluteal endometrium, harbouring differentiated and senescent subpopulations in both glands and stroma. We show that acute senescence in glandular epithelium drives secretion of multiple canonical implantation factors, whereas in the stroma it calibrates the emergence of anti-inflammatory decidual cells and pro-inflammatory senescent decidual cells. Pharmacological inhibition of stress responses in pre-decidual cells accelerated decidualization by eliminating the emergence of senescent decidual cells. In co-culture experiments, accelerated decidualization resulted in entrapment of collapsed human blastocysts in a robust, static decidual matrix. By contrast, the presence of senescent decidual cells created a dynamic implantation environment, enabling embryo expansion and attachment, although their persistence led to gradual disintegration of assembloids. Our findings suggest that decidual senescence controls endometrial fate decisions at implantation and highlight how endometrial assembloids may accelerate the discovery of new treatments to prevent reproductive failure.

"All-In-One" Genetic Tool Assessing Endometrial Receptivity for Personalized Screening of Female Sex Steroid Hormones

Endometrium is the uterine lining that undergoes hundreds of cycles of proliferation, differentiation, and desquamation throughout a woman's reproductive life. Recently, much attention is paid to the appropriate endometrial functioning, as decreased endometrial receptivity is stated to be one of the concerns heavily influencing successes of embryo implantation rates and the efficacy of in vitro fertilization (IVF) treatment. In order to acquire and maintain the desired endometrial receptivity during IVF cycles, luteal phase support by various progestagens or other hormonal combinations is generally recommended. However, today, the selection of the specific hormonal therapy during IVF seems to be empirical, mainly due to a lack of appropriate tools for personalized approach. Here, we designed the genetic tool for patient-specific optimization of hormonal supplementation schemes required for the maintenance of endometrial receptivity during luteal phase. We optimized and characterized in vitro endometrial stromal cell (ESC) decidualization model as the adequate physiological reflection of endometrial sensitivity to steroid hormones. Based on the whole transcriptome RNA sequencing and the corresponding bioinformatics, we proposed that activation of the decidual prolactin (PRL) promoter containing ancient transposons MER20 and MER39 may reflect functioning of the core decidual regulatory network. Furthermore, we cloned the sequence of decidual PRL promoter containing MER20 and part of MER39 into the expression vector to estimate the effectiveness of ESC decidual response and verified sensitivity of the designed system. We additionally confirmed specificity of the generated tool using human diploid fibroblasts and adipose-derived human mesenchymal stem cells. Finally, we demonstrated the possibility to apply our tool for personalized hormone screening by comparing the effects of natural progesterone and three synthetic analogs (medroxyprogesterone 17-acetate, 17α-hydroxyprogesterone caproate, dydrogesterone) on decidualization of six ESC lines obtained from patients planning to undergo the IVF procedure. To sum up, we developed the "all-in-one" genetic tool based on the MER20/MER39 expression cassette that provides the ability to predict the most appropriate hormonal cocktail for endometrial receptivity maintenance specifically and safely for the patient, and thus to define the personal treatment strategy prior to the IVF procedure.

MiR-148a-3p may contribute to flawed decidualization in recurrent implantation failure by modulating HOXC8

PURPOSE

To evaluate whether miR-148a-3p overexpression is associated with disrupted decidualization of recurrent implantation failure (RIF).

METHODS

Endometrial miRNA and mRNA expression profiles during the implantation window derived from women with and without RIF were identified using microarray and RT-qPCR. Immortalized human endometrial stromal cells (HESCs) were cultured for proliferation and in vitro decidualization assays after enhancing miR-148a-3p expression or inhibiting putative target gene homeobox C8 (HOXC8) expression. RT-qPCR, western blot, and luciferase reporter assays were used to confirm the relationship between miR-148a-3p and HOXC8 gene.

RESULTS

MiR-148a-3p was significantly upregulated in RIF endometrial tissues. Forced expression of miR-148a-3p notably attenuated HESC in vitro decidualization. Mechanistic studies revealed that miR-148a-3p directly bounds to the HOXC8 3' untranslated region (3'UTR) and suppressed HOXC8 expressions in both mRNA and protein levels. Further investigations demonstrated that inhibition of HOXC8 in HESCs induced similar effects on decidual process as those induced by miR-148a-3p overexpression.

CONCLUSION

Taken together, our findings suggested that elevated miR-148a-3p might account for flawed decidualization in RIF by negatively regulating HOXC8, raising the possibility that miR-148a-3p might be a novel therapeutic target in RIF.