Activin and inhibin signaling: From regulation of physiology to involvement in the pathology of the female reproductive system

Activin Signaling Pathway Specialization During Embryonic and Skeletal Muscle Development in Rainbow Trout (Oncorhynchus mykiss)

Activin signaling is essential for proper embryonic, skeletal muscle, and reproductive development. Duplication of the pathway in teleost fish has enabled diversification of gene function across the pathway but how gene duplication influences the function of activin signaling in non-mammalian species is poorly understood. Full characterization of activin receptor signaling pathway expression was performed across embryonic development and during early skeletal muscle growth in rainbow trout (RBT, Oncorhynchus mykiss). Rainbow trout are a model salmonid species that have undergone two additional rounds of whole genome duplication. A small number of genes were expressed early in development and most genes increased expression throughout development. There was limited expression of activin Ab in RBT embryos despite these genes exhibiting significantly elevated expression in post-hatch skeletal muscle. CRISPR editing of the activin Aa1 ohnolog and subsequent production of meiotic gynogenetic offspring revealed that biallelic disruption of activin Aa1 did not result in developmental defects, as occurs with knockout of activin A in mammals. The majority of gynogenetic offspring exhibited homozygous activin Aa1 genotypes (wild type, in-frame, or frameshift) derived from the mosaic founder female. The research identifies mechanisms of specialization among the duplicated activin ohnologs across embryonic development and during periods of high muscle growth in larval and juvenile fish. The knowledge gained provides insights into potential viable gene-targeting approaches for engineering the activin receptor signaling pathway and establishes the feasibility of employing meiotic gynogenesis as a tool for producing homozygous F1 genome-edited fish for species with long-generation times, such as salmonids.

The multifaceted role of insulin-like growth factor binding protein 7

Insulin-like growth factor binding protein 7 (IGFBP7) serves as a crucial extracellular matrix protein, exerting pivotal roles in both physiological and pathological processes. This comprehensive review meticulously delineates the structural attributes of IGFBP7, juxtaposing them with other members within the IGFBP families, and delves into the expression patterns across various tissues. Furthermore, the review thoroughly examines the multifaceted functions of IGFBP7, encompassing its regulatory effects on cell proliferation, apoptosis, and migration, elucidating the underlying mechanistic pathways. Moreover, it underscores the compelling roles in tumor progression, acute kidney injury, and reproductive processes. By rigorously elucidating the diverse functionalities and regulatory networks of IGFBP7 across various physiological and pathological contexts, this review aims to furnish a robust theoretical framework and delineate future research trajectories for leveraging IGFBP7 in disease diagnosis, therapeutic interventions, and pharmaceutical innovations.

Gonadotropin elevation is ootoxic to ovulatory oocytes and inhibits oocyte maturation, and activin decoy receptor ActRIIB:Fc therapeutically restores maturation

BACKGROUND

Elevated FSH often occurs in women of advanced maternal age (AMA, age ≥ 35) and in infertility patients undergoing controlled ovarian stimulation (COS). There is controversy on whether high endogenous FSH contributes to infertility and whether high exogenous FSH adversely impacts patient pregnancy rates.

METHODS

The senescence-accelerated mouse-prone-8 (SAMP8) model of female reproductive aging was employed to assess the separate impacts of age and high FSH activity on the percentages (%) of viable and mature ovulated oocytes recovered after gonadotropin treatment. Young and midlife mice were treated with the FSH analog equine chorionic gonadotropin (eCG) to model both endogenous FSH elevation and exogenous FSH elevation. Previously we showed the activin inhibitor ActRIIB:Fc increases oocyte quality by preventing chromosome and spindle misalignments. Therefore, ActRIIB:Fc treatment was performed in an effort to increase % oocyte viability and % oocyte maturation.

RESULTS

The high FSH activity of eCG is ootoxic to ovulatory oocytes, with greater decreases in % viable oocytes in midlife than young mice. High FSH activity of eCG potently inhibits oocyte maturation, decreasing the % of mature oocytes to similar degrees in young and midlife mice. ActRIIB:Fc treatment does not prevent eCG ootoxicity, but it restores most oocyte maturation impeded by eCG.

CONCLUSIONS

FSH ootoxicity to ovulatory oocytes and FSH maturation inhibition pose a paradox given the well-known pro-growth and pro-maturation activities of FSH in the earlier stages of oocyte growth. We propose the FOOT Hypothesis ("FSH OoToxicity Hypothesis), that FSH ootoxicity to ovulatory oocytes comprises a new driver of infertility and low pregnancy success rates in DOR women attempting spontaneous pregnancy and in COS/IUI patients, especially AMA women. We speculate that endogenous FSH elevation also contributes to reduced fecundity in these DOR and COS/IUI patients. Restoration of oocyte maturation by ActRIB:Fc suggests that activin suppresses oocyte maturation in vivo. This contrasts with prior studies showing activin A promotes oocyte maturation in vitro. Improved oocyte maturation with agents that decrease endogenous activin activity with high specificity may have therapeutic benefit for COS/IVF patients, COS/IUI patients, and DOR patients attempting spontaneous pregnancies.

Circular RNA circRPS19 promotes chicken granulosa cell proliferation and steroid hormone synthesis by interrupting the miR-218-5p/INHBB axis

Ovarian follicle development is an important physiological activity for females and makes great significance in maintaining female health and reproduction performance. The development of ovarian follicle is mainly affected by the granulosa cells (GCs), whose growth is regulated by a variety of factors. Here, we identified a novel circular RNA (circRNA) derived from the Ribosomal protein S19 (RPS19) gene, named circRPS19, which is differentially expressed during chicken ovarian follicle development. Further explorations identified that circRPS19 promotes GCs proliferation and steroid hormone synthesis. Furthermore, circRPS19 was found to target and regulate miR-218-5p through a competitive manner with endogenous RNA (ceRNA). Functionals investigation revealed that miR-218-5p attenuates GCs proliferation and steroidogenesis, which is opposite to that of circRPS19. In addition, we also confirmed that circRPS19 upregulates the expression of Inhibin beta B subunit (INHBB) by binding with miR-218-5p to facilitate GCs proliferation and steroidogenesis. Overall, this study revealed that circRPS19 regulates GCs development by releasing the repression of miR-218-5p on INHBB, which suggests a novel mechanism in respect to circRNA and miRNA regulation in ovarian follicle development.

Long non-coding RNAs: a summary of their roles in placenta development and pathology†

Long non-coding RNAs are cellular transcripts that have ˃200 nucleotides in length and do not code for proteins. Due to their low expression levels, long non-coding RNAs were previously considered as mere transcriptional noise. However, current evidence indicates that they regulate a myriad of biological processes such as cell proliferation, invasion, and apoptosis. Hence, their expression patterns are crucial indicators of the physiological or pathological states of cells, tissues, and organs. The utilization of long non-coding RNAs as biomarkers and therapeutic targets for the clinical management of several diseases have been suggested. Gradually, long non-coding RNAs are gaining a substantial attention in the field of feto-maternal medicine. After embryo implantation, the interactions between the trophoblast cells from the embryo and the uterus of the mother facilitate placenta development and pregnancy progression. These processes are tightly regulated, and their impairments result in pregnancy pathologies such as miscarriage and preeclampsia. Accumulating evidence implicates long non-coding RNAs in these processes. Herein, we have summarized the roles of several long non-coding RNAs in human placenta development, have proposed some mechanisms by which they participate in physiological and pathological placentation, have revealed some knowledge deficits, and have recommended ideal experimental approaches that will facilitate the clarification of the mechanistic actions of each long non-coding RNA at the feto-maternal interface during healthy and pathological pregnancies.

Bisphenol S moderately decreases the expression of syncytiotrophoblast marker genes and induces apoptosis in human trophoblast lineages

Bisphenol S (BPS) is currently used in the manufacturing of several household equipment such as water pipes and food containers. Hence, its entrance into the human body is almost inevitable. The presence of BPS in body fluids has been reported. However, its potential toxicity, especially on human placenta development and pregnancy progression, has not been explored. In this study, we assessed the impacts of BPS on the self-renewal and differentiation potentials of placental stem cells, also known as trophoblast stem cells (TSCs), by exposing them to three different BPS concentrations during their self-renewal and differentiation into syncytiotrophoblast (ST), extravillous trophoblast (EVT), and trophoblast organoids. Interestingly, BPS treatment did not affect the stemness, cell cycle and proliferation of the TSCs but it induced apoptosis in each trophoblast lineage. BPS altered the expression of several fusion-related genes. However, this alteration did not translate into significant morphological defects in the STs and organoids. Moreover, BPS did not impair the differentiation of TSCs into EVTs. These findings suggest that the presence of BPS at the feto-maternal interface may exaggerate trophoblast apoptosis and moderately inhibit the trophoblast fusion pathway to affect placenta development and pregnancy. Our study offers valuable insights into the potential toxicity of BPS on human placenta development, emphasizing the need for epidemiological assessment of the relationship between maternal serum levels of BPS and pregnancy complications.

Mechanistic actions of long non-coding RNA MALAT1 within the ovary and at the feto-maternal interface

Long non-coding RNAs (LncRNAs) are being unveiled as crucial regulators of several biological processes and pathways. Among the lncRNAs is metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), which is also known as nuclear enriched abundant transcript 2 (NEAT2). MALAT1 is highly conserved in mammals, and controls cellular processes such as proliferation, migration, invasion, angiogenesis, and apoptosis in both physiological and pathological conditions. Roles of MALAT1 in the female reproductive system are gradually getting explored. Within the ovarian micro-environment, the physiological expression of MALAT1 potentially modulates folliculogenesis while its upregulation promotes the metastasis of epithelial ovarian cancers. Interestingly, women with polycystic ovary syndrome have been shown to exhibit aberrant ovarian expression of MALAT1 and this is believed to contribute to the development of the disease. At the feto-maternal interface, MALAT1 potentially promotes trophoblast development. While its placental downregulation is linked to the pathogenesis of preeclampsia, its placental upregulation is associated with placenta increta and placenta percreta. Hence, abnormal expression of MALAT1 is a candidate molecular biomarker and therapeutic target for the treatment of these obstetric and gynecologic anomalies. To enhance a quick uncovering and detailed characterization of the mechanistic actions of MALAT1 in the female reproductive system, we have highlighted some knowledge deficits and have recommended ideal experimental models to be employed in prospective investigations.

Long noncoding RNA H19 in ovarian biology and placenta development

As the first long noncoding RNA to be discovered, H19 has gained substantial attention as a key regulator of several biological processes and its roles in female reproductive biology are gradually getting revealed. Herein, we have summarized the current evidence regarding H19 expression pattern and involvement in the developmental and pathological processes associated with the ovary and the placenta. The findings indicate that within the ovaries, H19 is expressed in the antral and cystic atretic follicles as well as in the corpora lutea but absent in the primordial, primary, and secondary follicles. Its normal expression promotes the maturation of antral follicles and prevents their premature selection for the ovulatory journey while its aberrant induction promotes polycystic ovary syndrome development and ovarian cancer metastasis. In the placenta, H19 is highly expressed in the cytotrophoblasts and extravillous trophoblasts but weakly expressed in the syncytiotrophoblast layer and potentially controls trophoblast cell fate decisions during placenta development. Abnormal expression of H19 is observed in the placental villi of pregnancies affected by pre-eclampsia and fetal growth restriction. Therefore, dysregulated H19 is a candidate biomarker and therapeutic target for the mitigation of ovarian and placenta-associated diseases.

TGF-β pathways in aging and immunity: lessons from Caenorhabditis elegans

The Transforming Growth Factor-β (TGF-β) superfamily of signaling molecules plays critical roles in development, differentiation, homeostasis, and disease. Due to the conservation of these ligands and their signaling pathways, genetic studies in invertebrate systems including the nematode Caenorhabditis elegans have been instrumental in identifying signaling mechanisms. C. elegans is also a premier organism for research in longevity and healthy aging. Here we summarize current knowledge on the roles of TGF-β signaling in aging and immunity.

Predisposing and Overall Effects of Reproductive Hormones on Breast Cancer: A Review

Cancer, the second leading cause of mortality worldwide, has been the subject of extensive and quickly changing scientific study and practice. Cancer remains a mystery despite the enormous effort put into understanding the genesis of cancerous cells, the development of malignant tissues, and the process by which they propagate and recur. Cells from humans that have been recruited by cancer and, to some extent, changed into pathogenic organisms or the foundation of tumors serve as agents of destruction. Understanding cancers leads to challenging philosophical issues since they undermine and use multicellular organization processes. Cancer metastasizing cells adopt new phenotypes while discarding previous behaviors. The absence of comprehensive knowledge of this has hampered the development of therapeutics for metastatic illness. For systems-level experimental and computational metastasis modeling, integrating these complex and interconnected features continues to be a problem because metastasis has typically been studied in separate physiological compartments. Lung, breast, and prostate cancers accounted for the bulk of the 18 million new cases of cancer that were diagnosed in 2018. The most frequent cancer in women is breast cancer. Animal experimentation plays a significant role in primary and translational breast cancer research. In theory, such breast cancer models should be comparable to breast cancer in humans in terms of tumor etiology, biological behavior, pathology, and treatment response.

Maternal Serum Activin A, Inhibin A and Follistatin-Related Proteins across Preeclampsia: Insights into Their Role in Pathogenesis and Prediction

BACKGROUND

Within the endocrine-paracrine signalling network at the maternal-foetal interface, the activin-inhibin-follistatin system modulates extravillous trophoblast invasion, suggesting a potential role in preeclampsia pathogenesis. This study aimed to compile the evidence published in the last decade regarding the variation in maternal serum activins, inhibin- and follistatin-related proteins in preeclamptic pregnancies compared to healthy pregnancies, and to discuss their role in predicting and understanding the pathophysiology of preeclampsia.

MATERIAL AND METHODS

A scoping review was conducted in MEDLINE, EMBASE and LILACS databases to identify studies published within the last ten years (2012-2022).

RESULTS

Thirty studies were included. None of the studies addressed maternal serum changes of isoforms different from activin A, inhibin A, follistatin, and follistatin-like 3. Sixteen studies evaluated the potential of these isoforms in predicting preeclampsia through the area under the curve from a receiver operating characteristic curve.

CONCLUSIONS

In preeclampsia, inhibin A is upregulated in all trimesters, whereas activin A increases exclusively in the late second and third trimesters. Serum follistatin levels are reduced in women with preeclampsia during the late second and third trimesters. However, changes in follistatin-like 3 remain inconclusive. Inhibin A and activin A can potentially serve as biomarkers of early-onset preeclampsia based on the outcomes of the receiver operating characteristic curve analysis. Further investigations are encouraged to explore the feasibility of quantifying maternal serum levels of activin A and inhibin A as a clinical tool in early preeclampsia prediction.

Placental transcriptome analysis of hypertensive pregnancies identifies distinct gene expression profiles of preeclampsia superimposed on chronic hypertension

BACKGROUND

The pathogenesis of preeclampsia superimposed on chronic hypertension (SI) is poorly understood relative to preeclampsia (PreE) occurring in pregnant people without chronic hypertension. Placental transcriptomes in pregnancies complicated by PreE and SI have not been previously compared.

METHODS

We identified pregnant people in the University of Michigan Biorepository for Understanding Maternal and Pediatric Health with hypertensive disorders affecting singleton, euploid gestations (N = 36) along with non-hypertensive control subjects (N = 12). Subjects were grouped as: (1) normotensive (N = 12), (2) chronic hypertensive (N = 13), (3) preterm PreE with severe features (N = 5), (4) term PreE with severe features (N = 11), (5) preterm SI (N = 3), or (6) term SI (N = 4). Bulk RNA sequencing of paraffin-embedded placental tissue was performed. The primary analysis assessed differential gene expression relative to normotensive and chronic hypertensive placentas, where Wald adjusted P values < 0.05 were considered significant. Unsupervised clustering analyses and correlation analyses were performed between conditions of interest, and a gene ontology was constructed.

RESULTS

Comparing samples from pregnant people with hypertensive diseases to non-hypertensive controls, there were 2290 differentially expressed genes. The log2-fold changes in genes differentially expressed in chronic hypertension correlated better with term (R = 0.59) and preterm (R = 0.63) PreE with severe features than with term (R = 0.21) and preterm (R = 0.22) SI. A relatively poor correlation was observed between preterm SI and preterm PreE with severe features (0.20) as well as term SI and term PreE with severe features (0.31). The majority of significant genes were downregulated in term and preterm SI versus normotensive controls (92.1%, N = 128). Conversely, most term and preterm PreE with severe features genes were upregulated compared to the normotensive group (91.8%, N = 97). Many of the upregulated genes in PreE with the lowest adjusted P values are known markers of abnormal placentation (e.g., PAAPA, KISS1, CLIC3), while the downregulated genes with the greatest adjusted P values in SI have fewer known pregnancy-specific functions.

CONCLUSIONS

We identified unique placental transcriptional profiles in clinically relevant subgroups of individuals with hypertension in pregnancy. Preeclampsia superimposed on chronic hypertension was molecularly distinct from preeclampsia in individuals without chronic hypertension, and chronic hypertension without preeclampsia, suggesting that preeclampsia superimposed on hypertension may represent a distinct entity.

Downregulated INHBB in endometrial tissue of recurrent implantation failure patients impeded decidualization through the ADCY1/cAMP signalling pathway

PURPOSE

This study aims to identify the mechanism of Inhibin Subunit Beta B (INHBB), a member of the transforming growth factor-β (TGF-β) family involved in the regulation of human endometrial stromal cells (HESCs) decidualization in recurrent implantation failure (RIF).

METHODS

RNA-seq was conducted to identify the differentially expressed genes in the endometria from control and RIF patients. RT-qPCR, WB, and immunohistochemistry were performed to analyse the expression levels of INHBB in endometrium and decidualised HESCs. RT-qPCR and immunofluorescence were used to detect changes in the decidual marker genes and cytoskeleton after knockdown INHBB. Then, RNA-seq was used to dig out the mechanism of INHBB regulating decidualization. The cAMP analogue (forskolin) and si-INHBB were used to investigate the involvement of INHBB in the cAMP signalling pathway. The correlation of INHBB and ADCY expression was analysed by Pearson's correlation analysis.

RESULTS

Our results showed significantly reduced expression of INHBB in endometrial stromal cells of women with RIF. In addition, INHBB was increased in the endometrium of the secretory phase and significantly induced in in-vitro decidualization of HESCs. Notably, with RNA-seq and siRNA-mediated knockdown approaches, we demonstrated that the INHBB-ADCY1-mediated cAMP signalling pathway regulates the reduction of decidualization. We found a positive association between the expression of INHBB and ADCY1 in endometria with RIF (R2 = 0.3785, P = 0.0005).

CONCLUSIONS

The decline of INHBB in HESCs suppressed ADCY1-induced cAMP production and cAMP-mediated signalling, which attenuated decidualization in RIF patients, indicating that INHBB is an essential component in the decidualization process.

Immunostaining of βA-Activin and Follistatin Is Decreased in HPV(+) Cervical Pre-Neoplastic and Neoplastic Lesions

The activin-follistatin system regulates several cellular processes, including differentiation and tumorigenesis. We hypothesized that the immunostaining of βA-activin and follistatin varies in neoplastic cervical lesions. Cervical paraffin-embedded tissues from 162 patients sorted in control (n = 15), cervical intraepithelial neoplasia (CIN) grade 1 (n = 38), CIN2 (n = 37), CIN3 (n = 39), and squamous cell carcinoma (SCC; n = 33) groups were examined for βA-activin and follistatin immunostaining. Human papillomavirus (HPV) detection and genotyping were performed by PCR and immunohistochemistry. Sixteen samples were inconclusive for HPV detection. In total, 93% of the specimens exhibited HPV positivity, which increased with patient age. The most detected high-risk (HR)-HPV type was HPV16 (41.2%) followed by HPV18 (16%). The immunostaining of cytoplasmatic βA-activin and follistatin was higher than nuclear immunostaining in all cervical epithelium layers of the CIN1, CIN2, CIN3, and SCC groups. A significant decrease (p < 0.05) in the cytoplasmic and nuclear immunostaining of βA-activin was detected in all cervical epithelial layers from the control to the CIN1, CIN2, CIN3, and SCC groups. Only nuclear follistatin immunostaining exhibited a significant reduction (p < 0.05) in specific epithelial layers of cervical tissues from CIN1, CIN2, CIN3, and SCC compared to the control. Decreased immunostaining of cervical βA-activin and follistatin at specific stages of CIN progression suggests that the activin-follistatin system participates in the loss of the differentiation control of pre-neoplastic and neoplastic cervical specimens predominantly positive for HPV.

Transcriptional profiles of TGF-β superfamily members in the lumbar DRGs and the effects of activins A and C on inflammatory pain in rats

Signaling by the transforming growth factor (TGF)-β superfamily is necessary for proper neural development and is involved in pain processing under both physiological and pathological conditions. Sensory neurons that reside in the dorsal root ganglia (DRGs) initially begin to perceive noxious signaling from their innervating peripheral target tissues and further convey pain signaling to the central nervous system. However, the transcriptional profile of the TGF-β superfamily members in DRGs during chronic inflammatory pain remains elusive. We developed a custom microarray to screen for transcriptional changes in members of the TGF-β superfamily in lumbar DRGs of rats with chronic inflammatory pain and found that the transcription of the TGF-β superfamily members tends to be downregulated. Among them, signaling of the activin/inhibin and bone morphogenetic protein/growth and differentiation factor (BMP/GDF) families dramatically decreased. In addition, peripherally pre-local administration of activins A and C worsened formalin-induced acute inflammatory pain, whereas activin C, but not activin A, improved formalin-induced persistent inflammatory pain by inhibiting the activation of astrocytes. This is the first report of the TGF-β superfamily transcriptional profiles in lumbar DRGs under chronic inflammatory pain conditions, in which transcriptional changes in cytokines or pathway components were found to contribute to, or be involved in, inflammatory pain processing. Our data will provide more targets for pain research.

Activin A Reduces Porcine Granulosa Cells Apoptosis via ERβ-Dependent ROS Modulation

Unfavorable conditions compromise animal reproduction by altering the ovarian granulosa cells' follicular dynamics and normal physiological function (GCs), eventually resulting in oxidative damage and cell apoptosis. Activin is produced in the GCs and plays a vital role in folliculogenesis. This study investigated the effects of activin A (ACT-A) treatment in vitro on the apoptosis of porcine GCs and the underlying molecular mechanism. We found that ACT-A could attenuate the apoptosis of the GCs and enhance the synthesis of estrogen (E2). ACT-A also enhanced FSH-induced estrogen receptor-β (ERβ) expression, inhibiting ERβ aggravated intracellular accumulation of the reactive oxygen species (ROS) and apoptosis. The E2 levels in the culture medium, the mRNA expression pattern of the apoptosis-related genes (CASPASE 3, BCL2, and BAX), steroidogenesis-related gene (CYP19A1), and cell viability were analyzed to confirm the results. In summary, this study indicated the protective role of ACT-A in apoptosis by attenuating the ROS accumulation through ERβ. These results aim to enhance the follicular functions and improve animal reproductive performance.

Comparing the potential for maternal-fetal signalling in oviparous and viviparous lizards

The evolution of a placenta requires several steps including changing the timing of reproductive events, facilitating nutrient exchange, and the capacity for maternal-fetal communication. To understand the evolution of maternal-fetal communication, we used ligand-receptor gene expression as a proxy for the potential for cross-talk in a live-bearing lizard (Pseudemoia entrecasteauxii) and homologous tissues in a related egg-laying lizard (Lampropholis guichenoti). Approximately 70% of expressed ligand/receptor genes were shared by both species. Gene ontology (GO) analysis showed that there was no GO-enrichment in the fetal membranes of the egg-laying species, but live-bearing fetal tissues were significantly enriched for 50 GO-terms. Differences in enrichment suggest that the evolution of viviparity involved reinforcing specific signalling pathways, perhaps to support fetal control of placentation. One identified change was in transforming growth factor beta signalling. Using immunohistochemistry, we show the production of the signalling molecule inhibin beta B (INHBB) occurs in viviparous fetal membranes but was absent in closely related egg-laying tissues, suggesting that the evolution of viviparity may have involved changes to signalling via this pathway. We argue that maternal-fetal signalling evolved through co-opting expressed signalling molecules and recruiting new signalling molecules to support the complex developmental changes required to support a fetus in utero. This article is part of the theme issue 'Extraembryonic tissues: exploring concepts, definitions and functions across the animal kingdom'.

Activin A Modulates Betaglycan Shedding via the ALK4-SMAD3-Dependent Pathway in Endometriotic Cells

The TGF-β superfamily members, activins and inhibins, are mainly involved in cell proliferation, cell survival, invasion, immune surveillance, and lesion growth in endometriosis. Herein, we investigated the modulation of the TGF-β type III receptor (betaglycan or BG) by activin A and inhibin A in endometriosis in vitro. Often, BG undergoes ectodomain shedding releasing soluble BG (sBG) which frequently antagonizes TGF-β signaling. The effects of activin A on BG shedding and signaling pathways involved were evaluated with the inhibitors LY364947 and SIS3, siRNA knockdown in human endometrial cells (12Z, THESC, Ishikawa, and primary stromal cells) and were quantified with BG ELISAs. The effects of activin A and inhibin A on the secretion of MMP2 and MMP3 were analyzed using ELISAs. The effects of activin A on the BG expression were analyzed using RT-qPCR and western blot. The CCK-8 and BrdU assays were used to evaluate the effects of the recombinant BG on cell viability and proliferation. Activin A stimulation resulted in a significant time- and dose-dependent reduction in BG shedding, which was found to be activin A/ALK-4/SMAD3- but not SMAD2-dependent. Activin A increased the BG mRNA expression but had no effect on the protein expression. Likewise, inhibin A was found to block BG shedding. Activin A, but not inhibin A, significantly enhanced the secretion of MMP2 and MMP3. The recombinant BG had no effect on the viability and proliferation of endometriotic cells. Together, these observations support a novel role for activin A with BG in modulating the TGF-β superfamily ligands in endometrial cells in vitro.

Follicle-stimulating hormone signaling in Sertoli cells: a licence to the early stages of spermatogenesis

Follicle-stimulating hormone signaling is essential for the initiation and early stages of spermatogenesis. Follicle-stimulating hormone receptor is exclusively expressed in Sertoli cells. As the only type of somatic cell in the seminiferous tubule, Sertoli cells regulate spermatogenesis not only by controlling their own number and function but also through paracrine actions to nourish germ cells surrounded by Sertoli cells. After follicle-stimulating hormone binds to its receptor and activates the follicle-stimulating hormone signaling pathway, follicle-stimulating hormone signaling will establish a normal Sertoli cell number and promote their differentiation. Spermatogonia pool maintenance, spermatogonia differentiation and their entry into meiosis are also positively regulated by follicle-stimulating hormone signaling. In addition, follicle-stimulating hormone signaling regulates germ cell survival and limits their apoptosis. Our review summarizes the aforementioned functions of follicle-stimulating hormone signaling in Sertoli cells. We also describe the clinical potential of follicle-stimulating hormone treatment in male patients with infertility. Furthermore, our review may be helpful for developing better therapies for treating patients with dysfunctional follicle-stimulating hormone signaling in Sertoli cells.

Ovarian expression of follicle stimulating hormone and activin receptors genes in a prenatally-androgenized rat model of polycystic ovary syndrome in adulthood

BACKGROUND

The expression of genes involved in basic pathways, such as folliculogenesis and steroidogenesis may be affected following prenatal androgen exposure. Besides, exposure to androgens during prenatal life plays a central role in developing polycystic ovary syndrome (PCOS) in females in later life. In the present study, we aimed to examine the expression of the follicle stimulating hormone receptor (FSHR) and activin receptor (actR) genes in ovarian granulosa cells (GCs) of a prenatally-androgenized rat model of PCOS in adulthood.

METHODS AND RESULTS

In the adult rat model of PCOS and their controls (n = 8 in each group), different phases of the estrous cycle were determined by vaginal smear. Total RNA was extracted from the ovarian GCs using the TRIzol protocol, a reverse transcription kit was used for complementary DNA (cDNA) synthesis, and the expression of FSHR and actR genes was measured by SYBR-Green Real-Time PCR. GraphPad Prism was used for statistical analysis of data, and the t-Student's test was used to compare the results between the two groups. PCOS rats had longer and irregular estrous cycles compared to controls. The expression of FSHR and actR genes were significantly decreased in the rat model of PCOS compared to control rats. In PCOS rats, genes expression ratios for FSHR and actR were 0.91 ± 0.11 times (P = 0.008) and 0.42 ± 0.13 times (P = 0.048) less than controls, respectively.

CONCLUSION

Reduced expression of the FSHR and actR genes in ovarian GCs may be one of the mechanisms mediating PCOS-related disorders, especially abnormal ovarian folliculogenesis and ovulation dysfunction, following exposure to androgens during fetal life.

The impact of bisphenol a (BPA) on the placenta

Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC) that is used in a wide-variety of plastic and common house-hold items. Therefore, there is potential continual exposure to this compound. BPA exposure has been linked to certain placenta-associated obstetric complications such as preeclampsia, fetal growth restriction, miscarriage, and preterm birth. However, how BPA exposure results in these disorders remains uncertain. Hence, we have herein summarized the reported impact of BPA on the morphology and metabolic state of the placenta and have proposed mechanisms by which BPA affects placentation, potentially leading to obstetric complications. Current findings suggest that BPA induces pathological changes in the placenta and disrupts its metabolic activities. Based on exposure concentrations, BPA can elicit apoptotic or anti-apoptotic signals in the trophoblasts; and can exaggerate trophoblast fusion while inhibiting trophoblast migration and invasion to affect pregnancy. Accordingly, the usage of BPA products by pregnant women should be minimized and less harmful alternative chemicals should be explored and employed where possible.

The role of fascin in carcinogenesis and embryo implantation

The cytoskeleton, with its actin bundling proteins, plays crucial roles in a host of cellular function, such as cancer metastasis, antigen presentation and trophoblast migration and invasion, as a result of cytoskeletal remodeling. A key player in cytoskeletal remodeling is fascin. Upregulation of fascin induces the transition of epithelial phenotypes to mesenchymal phenotypes through complex interaction with transcription factors. Fascin expression also regulates mitochondrial F-actin to promote oxidative phosphorylation (OXPHOS) in some cancer cells. Trophoblast cells, on the other hand, exhibit similar physiological functions, involving the upregulation of genes crucial for its migration and invasion. Owing to the similar tumor-like characteristics among cancer and trophoblats, we review recent studies on fascin in relation to cancer and trophoblast cell biology; and based on existing evidence, link fascin to the establishment of the maternal-fetal interface.

Serum and urine levels of activin A in primigravidae and multigravidae: a prospective cross-sectional study

The aim of the present study was to investigate serum and urine levels of activin A in different moments of gestation, in primigravidae and in multigravidae, to understand whether these variables (biological sample and first gestation) affect activin A as a biomarker in pregnancy. We prospectively included 43 pairs of serum and urine samples from 25 women examined at different gestational ages (range 45 to 268 days). In the group of primigravidae (n = 16 samples from 9 participants), there was no significant change in serum activin A levels across gestation. Conversely, the group of multigravidae (n = 27 samples from 16 women) had higher serum activin A levels in the third trimester (2676 ± 840 pg/ml) compared to the first (583 ± 408 pg/ml) and second (1040 ± 384) trimesters (p = .025). Urine activin A concentrations did not differ between the two groups and did not change according to the gestation phase. There was no correlation between serum and urinary levels of activin A (r = 0.149, p = .359). These data suggest that activin A secretion may vary less during the first pregnancy, while urine activin A is unlikely to be a surrogate for the systemic levels of this hormone in pregnant women.

Iodothyronine deiodinase 2 (DiO2) regulates trophoblast cell line cycle, invasion and apoptosis; and its downregulation is associated with early recurrent miscarriage

INTRODUCTION

Trophoblast development is a crucial event in placentation and pregnancy complications but its underlying mechanisms remain unclear. Thus, we aimed at investigating the role of DiO2 in trophoblast cell line decisions and assessing its placental villous expression in early recurrent miscarriage (ERM) patients.

METHODS

The placental villous expression of DiO2 was determined with immunofluorescence. Cell proliferation was measured with the CCK8 kit while cell-cycle and apoptosis were studied with flow-cytometry. Cell migration and invasion were measured with wound-healing and transwell assays, respectively. Gene expression was then assessed with RT-qPCR and western blotting.

RESULTS

DiO2 is expressed in the CTB, PCT, DCT and STB of the placenta. Its overexpression arrested trophoblast cell line proliferation at the G1 phase of the cell-cycle by downregulating cyclin-D1 and PCNA, while promoting apoptosis via increased caspase-3 activity and inhibition of the AKT and ERK1/2 signaling pathways. Also, it augmented trophoblast cell line migration and invasion via the upregulation of N-cadherin, vimentin, fascin-1, twist-1 and other epithelial-mesenchymal transition genes. DiO2 knockdown elicited the opposite effects. Surprisingly, each of these effects of DiO2 manipulation was not mediated by thyroid hormone metabolism. Assessment of the ERM placental villi revealed a downregulation of DiO2, N-cadherin, vimentin, fascin-1 and twist-1. The expression of E-cadherin remained unchanged in these placentae.

DISCUSSION

During placentation, DiO2 may inhibit trophoblast proliferation while facilitating their differentiation into an invasive phenotype; and that its downregulation may contribute to the shallow trophoblast invasion that precedes ERM. Hence, DiO2 is a potential therapeutic target against ERM.

Sex Maintenance in Mammals

The crucial event in mammalian sexual differentiation occurs at the embryonic stage of sex determination, when the bipotential gonads differentiate as either testes or ovaries, according to the sex chromosome constitution of the embryo, XY or XX, respectively. Once differentiated, testes produce sexual hormones that induce the subsequent differentiation of the male reproductive tract. On the other hand, the lack of masculinizing hormones in XX embryos permits the formation of the female reproductive tract. It was long assumed that once the gonad is differentiated, this developmental decision is irreversible. However, several findings in the last decade have shown that this is not the case and that a continuous sex maintenance is needed. Deletion of Foxl2 in the adult ovary lead to ovary-to-testis transdifferentiation and deletion of either Dmrt1 or Sox9/Sox8 in the adult testis induces the opposite process. In both cases, mutant gonads were genetically reprogrammed, showing that both the male program in ovaries and the female program in testes must be actively repressed throughout the individual's life. In addition to these transcription factors, other genes and molecular pathways have also been shown to be involved in this antagonism. The aim of this review is to provide an overview of the genetic basis of sex maintenance once the gonad is already differentiated.

The Involvement of Cell Adhesion Molecules, Tight Junctions, and Gap Junctions in Human Placentation

Placentation is a major determinant of the success of pregnancy. It is regulated by several factors such as cell adhesion molecules, tight junctions, and gap junctions. The cell adhesion molecules are integrins, cadherins, immunoglobulins, nectins, and selectins. The tight junctions are composed of claudins, occludin, and junction adhesion molecule proteins while the gap junctions are composed of connexins of varying molecular weights. During placentation, some of these molecules regulate trophoblast proliferation, trophoblast fusion, trophoblast migration, trophoblast invasion, trophoblast-endothelium adhesion, glandular remodeling, and spiral artery remodeling. There is a dysregulated placental expression of some of these molecules during obstetric complications. We have, hereby, indicated the expression patterns of the subunits of each of these molecules in the various trophoblast subtypes and in the decidua, and have highlighted their involvement in physiological and pathological placentation. The available evidence points to the relevance of these molecules as distinguishing markers of the various trophoblast lineages and as potential therapeutic targets in the management of malplacentation-mediated diseases.

Ephrin and Eph receptor signaling in female reproductive physiology and pathology†

Ephrins are ligands of Eph receptors (Ephs); both of which are sorted into two classes, A and B. There are five types of ephrin-As (ephrin-A1-5) and three types of ephrin-Bs (ephrin-B1-3). Also, there are 10 types of EphAs (EphA1-10) and six types of EphBs (EphB1-6). Binding of ephrins to the Eph receptors activates signaling cascades that regulate several biological processes such as cellular proliferation, differentiation, migration, angiogenesis, and vascular remodeling. Clarification of their roles in the female reproductive system is crucial to understanding the physiology and pathology of this system. Such knowledge will also create awareness regarding the importance of these molecules in diagnostic, prognostic, and therapeutic medicine. Hence, we have discussed the involvement of these molecules in the physiological and pathological events that occur within the female reproductive system. The evidence so far suggests that the ephrins and the Eph receptors modulate folliculogenesis, ovulation, embryo transport, implantation, and placentation. Abnormal expression of some of these molecules is associated with polycystic ovarian syndrome, ovarian cancer, tubal pregnancy, endometrial cancer, uterine leiomyoma (fibroids), cervical cancer, and preeclampsia, suggesting the need to utilize these molecules in the clinical setting. To enhance a quick development of this gradually emerging field in female reproductive medicine, we have highlighted some "gaps in knowledge" that need prospective investigation.

An exome-wide exploration of cases of primary ovarian insufficiency uncovers novel sequence variants and candidate genes

Primary ovarian insufficiency (POI) implies the cessation of menstruation for several months in women before the age of 40 years and is a major cause of infertility. The study of the contribution of genetic factors to POI has been fueled by the use of whole exome sequencing (WES). Here, to uncover novel causative pathogenic variants and risk alleles, WES has been performed in 12 patients with familial POI (eight unrelated index cases and two pairs of sisters) and six women with early menopause and family history of POI (four index cases and one pair of sisters). Likely causative variants in NR5A1 and MCM9 genes were identified as well as a variant in INHA that requires further investigation. Moreover, we have identified more than one candidate variant in 3 out of 15 familial cases. Taken together, our results highlight the genetic heterogeneity of POI and early menopause and support the hypothesis of an oligogenic inheritance of such conditions, in addition to monogenic inheritance.