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Qi Zhu, Yi-Chao Dong, Lu Zhang, Xu Ma and Hong-Fei Xia

Missed abortion (MA) is a common disease in obstetrics and gynecology. More and more studies have focused on the relationship between miRNAs and pregnancy maintenance and its related diseases. The aim of this article is to explore the relationship between miRNA and MA. The expression of miR-98 were detected by in situ hybridization and real-time PCR. Cell proliferation, activity and migration were measured via Edu, MTT, and transwell assays. The target genes of miR-98 are identified by dual-luciferase activity assay. And the expression levels of target genes were determined by Western blot, real-time PCR and immunohistochemistry. miR-98 was significantly up-regulated in placental villi from over 35 years old MA patients compared with the age-matched normal pregnant women. Up-regulation of miR-98 suppressed the proliferation, activity and migration of the human trophoblast HTR-8/SVneo cell in vitro. miR-98 could bind to GDF6 and FAPP2 mRNA 3’-UTR and negatively regulate their expression. The downregulation of miR-98 promoted cell proliferation, then knockdown of GDF6 or FAPP2 inhibited miR-98-mediated cell proliferation. GDF6 and FAPP2 expression in the placental villi from MA patients were decreased compared to normal placental tissues. The expression of miR-98 in MA had an opposite relationship with the expression of GDF6 and FAPP2. Overexpression of miR-98 is associated with the occurrence of MA. miR-98 prevents proliferation, viability and migration of trophoblast cells partially through targeting GDF6 and FAPP2.

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Elizabeth K McReight, Seng H Liew, Sarah E Steane, Karla J Hutt, Karen M Moritz and Lisa K Akison

Prenatal alcohol exposure (PAE) has been associated with reproductive dysfunction in offspring. However, studies in females, particularly examining long-term infertility or impacts on ovarian reserve, are lacking. The current study utilised a moderate, episodic exposure model in rats to mimic ‘special occasion’ drinking, which is reported to be common during pregnancy. Our objective was to examine the consequences of this prenatal alcohol exposure on reproductive parameters in female offspring. Pregnant Sprague–Dawley rats were treated with either an ethanol gavage (1 g EtOH/kg body weight), or an equivalent volume of saline, on embryonic days 13.5 and 14.5 of pregnancy, resulting in a peak blood alcohol concentration of ~0.04%. Neonatal female offspring were examined for molecular markers regulating early follicle numbers in the ovary, and unbiased stereology was used to quantify primordial and early growing follicle numbers. Puberty onset (age at vaginal opening and first estrous) was measured post-weaning, and estrous cycles, reproductive hormones (progesterone and estradiol) and pregnancy success was measured in adults (5–6 months of age). We found no evidence that any of these reproductive parameters were significantly altered by PAE in this model. This animal study provides some reassurance for women who may have consumed a small amount of alcohol during their pregnancy. However, previously published effects on offspring metabolism using this model reinforce avoidance of alcohol during pregnancy.

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Fabiane de Santi, Isadora Dantas Lunardi, Flávia Luciana Beltrame, Paulo Sérgio Cerri and Estela Sasso-Cerri

In epididymis, cimetidine induces androgenic failure due to reduced sex hormone-binding globulin stromal levels and blockade of androgen receptor (AR) nuclear import. UCHL1, a hydrolase of ubiquitin-proteasome system (UPS), seems to play a role in autophagy and apoptotic pathway. However, the role of UPS and autophagy in epididymis has not been clarified. We evaluated UCHL1 and autophagy in epididymal cauda epithelium under androgenic deficiency induced by cimetidine, focusing on the interplay among these processes and apoptosis. The integrity of epididymal muscular layer was also evaluated. Male rats received cimetidine (CMTG) or saline (CG). Seminal vesicles were weighed, the expression of androgen-responsive genes Crisp1 and connexin 43 (Cx43) in cauda epididymis was evaluated, and cauda fragments were processed for light and transmission electron microscopy. The epithelium height and muscular thickness were measured. TUNEL, immunohistochemistry for caspase-3 and Cx43, and immunofluorescence for AR, Bcl-2, UCHL1, MAP LC3A, and p62/SQSTM1 (autophagic markers) were performed. Bcl-2, UCHL1, and Cx43 were detected by Western blot. In CMTG, the reduction in seminal vesicles weight accompanied by downregulation of Crisp1 and Cx43 confirmed epididymal androgenic failure. These results were associated with muscular atrophy, apoptosis and weak Cx43 and AR immunoexpression, supporting the androgenic dependence of muscular integrity. The high UCHL1 levels and reduction in Bcl-2 reinforce UCHL1 role in epithelial cells death. The intense immunoexpression of LC3A and p62/SQSTM1 indicates autophagic disturb, which in association with high UCHL1 levels, points to a role of UPS and autophagy in the regulation of epididymal epithelial cells viability under androgenic control.

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Victor E Gomez-León, O J Ginther, Rafael R Domingues, José D Guimarães and Milo C Wiltbank

Previous research demonstrated that acute treatment with GnRH antagonist, Acyline, allowed follicle growth until ~8.5 mm and no dominant follicle was selected. This study evaluated whether deficient LH was the underlying mechanism for Acyline effects by replacing LH action, using human chorionic gonadotropin (hCG), during Acyline treatment. Holstein heifers (n = 24) during first follicular wave were evaluated by ultrasound and randomized into one of three treatments: Control (saline treatments), Acyline (5 µg/kg Acyline), or Acyline+hCG (Acyline plus 50 IU of hCG at start then 100 IU every 12 h). Pulses of LH were present in Control heifers (9 Pulses/10 h) but not during Acyline treatment. Data were normalized to the transition to diameter deviation (day 0; F1 ~7.5 mm). Diameter deviation of the largest (F1) and the second largest (F2) follicle was not observed in Acyline-treated heifers, whereas control heifers had decreased growth of F2 at F1 ~7.5 mm, indicating deviation. Selection of a single dominant follicle was restored by providing LH activity in Acyline+hCG heifers, as evidenced by F1 and F2 deviation, continued growth of F1, and elevated circulating estradiol. Separation of F1 and F2 occurred 12 h (~7.0 mm) earlier in Acyline+hCG heifers than Controls. Circulating FSH was greater in Acyline than Controls, but lower in Acyline+hCG than Controls after day 1.5. In conclusion, dominant follicle selection and growth after follicle deviation is due to LH action as shown by inhibition of this process during ablation of GnRH-stimulated LH pulses with Acyline and restoration of it after replacement of LH action by hCG treatment.

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Graham J Burton, Tereza Cindrova-Davies, Hong wa Yung and Eric Jauniaux

Development of the human placenta takes place in contrasting oxygen concentrations at different stages of gestation, from ~20 mmHg during the first trimester rising to ~60 mmHg at the start of the second trimester before gradually declining to ~40 mmHg at term. In view of these changes the early placenta has been described as ‘hypoxic’. However, placental metabolism is heavily glycolytic, supported by the rich supply of glucose from the endometrial glands, and there is no evidence of energy compromise. On the contrary, the trophoblast is highly proliferative, with the physiological low-oxygen environment promoting maintenance of stemness in progenitor populations. These conditions favour formation of the cytotrophoblastic shell that encapsulates the conceptus, and interfaces with the endometrium. Extravillous trophoblast cells on the outer surface of the shell undergo an epithelial-mesenchymal transition and acquire invasive potential. Experimental evidence suggests these changes may be mediated by the higher oxygen concentration present within the placental bed. Interpreting in vitro data is often difficult, however, due to the use of non-physiological oxygen concentrations and trophoblast-like cell lines or explant models. Trophoblast is more vulnerable to hyperoxia or fluctuating levels of oxygen than hypoxia, and some degree of placental oxidative stress likely occurs in all pregnancies towards term. In complications of pregnancy, such as early-onset pre-eclampsia, malperfusion generates high levels of oxidative stress, causing release of factors that precipitate the maternal syndrome. Further experiments are required using genuine trophoblast progenitor cells and physiological concentrations to fully elucidate the pathways by which oxygen regulates placental development.

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Nathan Treff, Diego Marin, Louis Lello, Stephen Hsu and Laurent Cam Tellier

Since its introduction to clinical practice, preimplantation genetic testing (PGT) has become a standard of care for couples at risk of having children with monogenic disease, and for chromosomal aneuploidy to improve outcomes for patients with infertility. The primary objective of PGT is to reduce the risk of miscarriage and genetic disease and to improve the success of infertility treatment with the delivery of a healthy child. Until recently, the application of PGT to more common but complex polygenic disease was not possible, as the genetic contribution to polygenic disease has been difficult to determine, and the concept of embryo selection across multiple genetic loci has been difficult to comprehend. Several achievements, including the ability to obtain accurate, genome-wide genotypes of the human embryo, and the development of population level biobanks have now made PGT for polygenic disease risk applicable in clinical practice. With the rapid advances in embryonic polygenic risk scoring, diverse considerations beyond technical capability have been introduced.

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Xiao-Bo Wang, Qian-Rong Qi, Kai-Lin Wu and Qing-Zhen Xie

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Shizu Aikawa, Jia Yuan, Amanda Dewar, Xiaofei Sun and Sudhansu K Dey

Mammary glands are comprised of ducts and terminal lobules that form tree-like structures. Luminal epithelial cells in these lobules undergo differentiation into alveolar cells in pregnancy to support milk production. This study reveals that Scribble (SCRIB), a scaffold protein expressed in progesterone receptor (PGR)-positive cells, plays a critical role in mammary gland alveologenesis in mice. We conditionally deleted Scrib using a Pgr-Cre driver. PGR is heterogeneously expressed throughout the luminal epithelium. Scrib loss in mammary glands by Pgr-Cre (Scribf/fPgrCre/+) shows inefficient alveologenesis and terminal end bud (TEB)-like morphology during pregnancy, resulting in poor milk production and subsequent death of pups after delivery. The differentiation of PGR-positive epithelial cells into Elf5-expressing alveolar cells is defective in Scribf/fPgrCre/+ mice. These changes are reflected in reduced activation of JAK2 and PAK1, resulting in downregulation of pSTAT5, a critical transcriptional factor for alveologenesis. These results provide evidence that SCRIB impacts PGR-positive cell lineage during alveologenesis, which impacts milk production and the health of offspring.

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Valentina Lodde, Rodrigo Garcia Barros, Priscila Chediek Dall’Acqua, Cecilia Dieci, Claude Robert, Alexandre Bastien, Marc-André Sirard, Federica Franciosi and Alberto Maria Luciano

In the last years, many studies focused on the understanding of the possible role of zinc in the control of mammalian oogenesis, mainly on oocyte maturation and fertilization. However, little is known about the role of zinc at earlier stages, when the growing oocyte is actively transcribing molecules that will regulate and sustain subsequent stages of oocyte and embryonic development. In this study, we used the bovine model to gain insights into the possible involvement of zinc in oocyte development. We first mined the EmbryoGENE transcriptomic dataset, which revealed that several zinc transporters and methallothionein are impacted by physiological conditions throughout the final phase of oocyte growth and differentiation. We then observed that zinc supplementation during in vitro culture of growing oocytes is beneficial to the acquisition of meiotic competence when subsequently subjected to standard in vitro maturation. Furthermore, we tested the hypothesis that zinc supplementation might support transcription in growing oocytes. This hypothesis was indirectly confirmed by the experimental evidence that the content of labile zinc in the oocyte decreases when a major drop in transcription occurs in vivo. Accordingly, we observed that zinc sequestration with a zinc chelator rapidly reduced global transcription in growing oocytes, which was reversed by zinc supplementation in the culture medium. Finally, zinc supplementation impacted the chromatin state by reducing the level of global DNA methylation, which is consistent with the increased transcription. In conclusion, our study suggests that altering zinc availability by culture-medium supplementation supports global transcription, ultimately enhancing meiotic competence.

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Inga Laezer, Sergio E Palma-Vera, Fan Liu, Marcus Frank, Nares Trakooljul, Andreas Vernunft, Jennifer Schoen and Shuai Chen

In mammals, around the time of ovulation, the hormonal profile dynamically changes in synchrony with reproductive events occurring in the oviduct, that is, sperm arrival, fertilization, and early embryo development. Extracellular vesicles (EVs) have been recently recognized as key components of the embryonic milieu; however, composition and function of oviductal EVs during this crucial period remains to be further explored. Therefore, we initially characterized EVs from porcine oviductal fluid specifically around the critical ovulation window: that is, estrus (E), late estrus (LE, day of expected ovulation), post ovulation (PO), and additionally diestrus (D). Total EV numbers gradually rose from D to E, LE and PO (P < 0.05), which corresponded to the total EV protein amount (P < 0.05). Strikingly, the mean size of EVs in PO was significantly smaller than in E and LE groups, which also had a lesser proportion of small EVs (P < 0.05). The EV protein cargoes during the periovulatory period were further analyzed by mass spectrometry. Qualitative analysis detected 1118 common proteins, which are most enriched in the cellular component of EVs/exosomes. Hierarchical clustering indicated similar protein profile within the biological replicates, but large discrepancy among stages. Further quantitative analysis discovered 34 and 4 differentially expressed proteins in the comparison between E and PO and in the comparison between E and LE, respectively. The dynamic EV protein profile together with the quick adaption in EV size and quantity suggests that porcine oviductal EV secretion are under the hormonal influence during the estrus cycle.