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Kacie A Norton, Ross Humphreys, Chelsey Weatherill, Kevin Duong, Vivian V Nguyen, Arun Kommadath, Farshad Niri, Paul Stothard, and Heather E McDermid

Defects in spermatogenesis are an important cause of male infertility. Multiple aspects of spermatogenesis are controlled by chromatin remodellers, including regulating transcription. We previously described mutations in chromatin remodelling gene Cecr2 that resulted in the lethal neural tube defect exencephaly in most mutant mice and subfertility in mice that were non-penetrant for exencephaly. Here, we show that the severity of male subfertility is dependent on age. Cecr2GT/Del males contain two mutant alleles, one of which is hypomorphic and therefore produces a small amount of protein. These males sire the fewest pups just after sexual maturity (88% fewer than Cecr2+/+ at P42–60) but improve with age (49% fewer than Cecr2+/+ at P81–100), although never completely recovering to Cecr2+/+(wild type) levels. When young, they also have defects in testis histology, in vivo fertilization frequency, sperm number and motility, and testis weight that show similar improvement with age. Immunostaining of staged seminiferous tubules showed CECR2 in type A, intermediate and B spermatogonia, and less in preleptotene and leptotene spermatocytes. Histological defects were first apparent in Cecr2GT/Del testes at P24, and RNA-seq analysis revealed 387 differentially expressed genes. This included 66 genes on the X chromosome (almost double the number on any other chromosome), all more highly expressed in Cecr2GT/Del testes. This inappropriate expression of X chromosome genes could be caused by a failure of effective meiotic sex chromosome inactivation. We identify several abnormally expressed genes that may contribute to defects in spermatogenesis at P24. Our results support a role for Cecr2 in juvenile spermatogenesis.

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Courtney Barber, Yann Yap, Natalie Josephine Hannan, Euan M Wallace, and Sarah Arwen Marshall

Preeclampsia is a multisystem hypertensive disorder of pregnancy that remains one of the leading causes of maternal and perinatal morbidity and mortality worldwide. The widespread maternal endothelial dysfunction that underlies preeclampsia is thought to arise from excessive placental production of various factors combined with enhanced oxidative stress. While previous studies have reported elevated activin A in women diagnosed with preeclampsia, whether activin A can cause vascular dysfunction has not yet been thoroughly investigated. Here, we demonstrated that different subtypes of activin A receptors were localised to the endothelial and smooth muscle cells of mouse and human aortae. Then, the aorta of healthy female C57Bl6J mice (n=8) were incubated for 24 hours in various concentrations of recombinant activin A to mimic early pregnancy (5ng/mL), late pregnancy (20ng/mL) and preeclampsia (50ng/mL). Vascular reactivity as assessed by wire myography revealed that only the preeclamptic level of activin A impaired agonist-mediated endothelium-dependent relaxation by reducing the vasodilator prostanoid contribution to relaxation. However, agonist-mediated endothelium-independent mechanisms were unaffected. Further investigations carried out on human aortic endothelial cells suggested that the impairment of aorta relaxation could also be driven by increased endothelial cell permeability, and decreased cell viability, adherence and proliferation. This is the first direct evidence to show that activin A can induce endothelial dysfunction in whole blood vessels, suggesting that at high circulating levels it may contribute to the widespread endothelial dysfunction in women with preeclampsia.

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Momoe Ito, Masato Unou, Toshiya Higuchi, Shuhei So, Masahiko Ito, and Keiichiro Yogo

Solute carrier 22a member 14 (SLC22A14) plays a critical role in male infertility in mice. We previously revealed that one of the causes of infertility is impaired capacitation. However, the molecular mechanism remained unclear. Here, we show that the influx of HCO3 , a trigger of capacitation, is impaired and intracellular pH (pHi) is decreased in the sperm of Slc22a14 knockout (KO) mice. While intracellular cAMP concentration did not increase during capacitation in Slc22a14 KO spermatozoa, HCO3 -dependent soluble adenylate cyclase activity was normal, and the addition of 8-bromo cAMP rescued the decreased protein tyrosine phosphorylation. In addition, the pHi of Slc22a14 KO sperm was lower than that of WT sperm and did not increase after the addition of HCO3 . Although its relationship to the regulation of pHi is unknown, transmembrane protein 225, a possible protein phosphatase inhibitor, was found to be decreased in Slc22a14 KO sperm. The decreased in vitro fertilization rate of Slc22a14 KO sperm was partially rescued by an increase in the pHi and the addition of 8-bromo cAMP. These results suggest that SLC22A14 is involved in capacitation through the regulation of HCO3 transport and pHi.

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Kashmira Bane, Junita Desouza, Asma Rojewale, Rajendra Katkam, Gwendolyn Fernandes, Raj Sawant, Uddhavraj Dudhedia, Neeta Warty, Anahita Chauhan, Uddhav Chaudhari, Rahul Gajbhiye, and Geetanjali Sachdeva

Recent data suggest that the DNA damage response (DDR) is altered in the eutopic endometrium (EE) of women with endometriosis and this probably ensues in response to higher DNA damage encountered by the EE in endometriosis. DDR operates in a tissue-specific manner and involves different pathways depending on the type of DNA lesions. Among these pathways, the non-homologous end joining (NHEJ) pathway plays a critical role in the repair of double-stranded DNA breaks. The present study was undertaken to explore whether NHEJ is affected in the EE of women with endometriosis. Towards this, we focused on the X-Ray Repair Cross-Complementing 4 (XRCC4) protein, one of the core components of the NHEJ pathway. Endometrial XRCC4 protein levels in the mid-proliferative phase were found significantly (p<0.05) downregulated in women with endometriosis, compared to control women. Investigation of a microarray-based largest dataset in the GEO database (GSE51981) revealed a similar trend at the transcript level in the EE of women with endometriosis, compared to control women. Further in-vitro studies were undertaken to explore the effects of H2O2-induced oxidative stress on DNA damage, as assessed by γ-H2AFX and 8-hydroxy-2’-deoxyguanosine (8-OHdG) immunolocalization, and XRCC4 protein levels in endometrial stromal (ThESCs) and epithelial (Ishikawa) cells. A significant decrease in XRCC4 protein levels and significantly higher localization of γ-H2AFX and 8-OHdG were evident in ThESCs and Ishikawa cells experiencing oxidative stress. Overall, the study demonstrates that the endometrial XRCC4 expression is dysregulated in women with endometriosis and this could be due to higher oxidative stress in endometriosis.

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Michele D Calder, Robert Chen, Anastasia MacDonald, Zoe MacNeily, Zuleika Chin Lai Leung, Samira Adus, Shiyu Cui, Dean Betts, Basim Abu Rafea, and Andrew J. Watson

As obese and overweight patients commonly display hyperlipidemia, and are increasingly accessing fertility clinics for their conception needs, our studies are directed at understanding the effects of hyperlipidemia on early pregnancy. We have focused on investigating palmitic acid (PA) and oleic acid (OA) treatment alone and in combination from the mouse two-cell stage as a model for understanding their effects on the mammalian preimplantation embryo. We recently reported that PA exerts a negative effect on mouse two-cell progression to the blastocyst stage, whereas OA co-treatment reverses that negative effect. In the present study, we hypothesized that PA treatment of mouse embryos would disrupt proper localization of cell fate determining and blastocyst formation gene products, and that co-treatment with oleic acid would reverse these effects. Our results demonstrate that PA treatment significantly (p<0.05) reduces blastocyst development and cell number but did not prevent nuclear localization of YAP in outer cells. PA treatment significantly reduced the number of OCT4+ and CDX2+ nuclei. PA treated embryos had lower expression of blastocyst formation proteins (E-cadherin, ZO-1 and Na/K-ATPase alpha1 subunit). Importantly, co-treatment of embryos with OA reversed PA-induced effects on blastocyst development and increased ICM and TE cell numbers and expression of blastocyst formation proteins. Our findings demonstrate that PA treatment does not impede cell fate gene localization but does disrupt proper blastocyst formation gene localization during mouse preimplantation development. OA treatment is protective and reverses PA’s detrimental effects. The results advance our understanding of the impact of FFA exposure on mammalian preimplantation development.

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Morgane Robles, Shavahn C Loux, Amanda M de Mestre, and Pascale Chavatte-Palmer

Equine placental development is a long process with unique features. Implantation occurs around 40 days of gestation (dpo) with the presence of a transient invasive placenta from 25-35dpo to 100-120dpo. The definitive non-invasive placenta remains until term (330d). This definitive placenta is diffuse and epitheliochorial, exchanging nutrients, gas and waste with the endometrium through microvilli, called microcotyledons. These are lined by an external layer of haemotrophic trophoblast. Moreover, histotrophic exchange remains active through the histotrophic trophoblast located along the areolae. Placental development is dependent on the maternal environment that can be affected by several factors (e.g., nutrition, metabolism, age, embryo technologies, pathologies) that may affect foetal development as well as long-term offspring health. The first section of the review focuses on normal placental development as well as definitive placental structure. Differences between the various areas of the placenta are also highlighted. The latter sections provide an overview of the effects of the maternal environment and reproductive pathologies, respectively, on trophoblast/placental gene expression and structure. So far, only pre-implantation and late gestation/term data are available, which demonstrate an important placental plasticity in response to environmental variation, with genes involved in oxidative stress and tissue differentiation mostly involved in the pre-implantation period, whereas genes involved in foeto-placental growth and nutrient transfers are mostly perturbed at term.

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Arantxa Cardona Barberán, Annekatrien Boel, Frauke Vanden Meerschaut, Dominic Stoop, and Björn Heindryckx

Two decades have passed since the discovery of phospholipase C zeta (PLCZ1) as the sperm oocyte activating factor. At present, there is a general consensus that PLCZ1 is responsible for triggering the calcium (Ca2+) oscillations necessary to start the oocyte activation process in mammals. One proof is that abnormal, reduced, or absent PLCZ1 in human spermatozoa leads to fertilization failure (FF) after intracytoplasmic sperm injection (ICSI). ICSI is the most effective assisted reproduction technique and enables overcoming almost all male infertility conditions. Despite fertilization rates of up to 80%, FF does occur in 1-3% of ICSI cycles, which leaves these patients with few options for obtaining genetically related offspring. Assisted oocyte activation (AOA) using Ca2+ ionophores has emerged as a useful treatment option for these patients. While AOA has been proven very beneficial for the treatment of sperm-related FF, some cases of female-related FF cannot be overcome by AOA. Therefore, the development of appropriate diagnostic tests that predict the prognosis of AOA treatment would be advantageous to improve the clinical management of these patients and shorten the time to pregnancy. The aim of this review is to provide an up-to-date overview of the genetic causes of FF after ICSI, and to discuss the advantages and disadvantages of using PLCZ1 as a diagnostic marker or therapeutic molecule in comparison with currently available diagnostic tests and treatments.

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Sha-Ting Lei, Ming-Qing Li, Yan-Ling Cao, Shu-Hui Hou, Hai-Yan Peng, Dong Zhao, and Jing Sun

Endometriosis (EMS) is a chronic benign inflammatory disease characterized by the growth of endometrial-like tissue in aberrant locations outside of the uterine cavity. Angiogenesis and abnormal immune responses are the fundamental requirements of endometriotic lesion survival in the peritoneal cavity. Follistatin-like I (FSTL1) is a secreted glycoprotein that exhibits varied expression levels in cardiovascular disease, cancer and arthritis. However, the role of FSTL1 in the development of EMS remains to be fully elucidated. Results of the present study demonstrated that the expression of FSTL1 was significantly increased in ectopic endometrial stromal cells (ESCs) and peritoneal fluid from patients with EMS, compared to the control group. Both conditions of hypoxia and estrogen treatment induced human ESCs to produce increased levels of FSTL1 and disco-interacting protein 2 homolog A (DIP2A). Furthermore, the expression levels of DIP2A, IL8 and IL1β were increased in FSTL1 overexpressed HESCs. Additionally, FSTL1 treatment increased the proliferation of HUVECs in a dose-dependent manner in vitro and markedly increased the tube formation of HUVECs. Moreover, treatment with FSTL1 facilitated M1 polarization of macrophages, increased the secretion of proinflammatory factors and inhibited the expression of scavenger receptor CD36. Results of the present study suggested that the elevated expression of FSTL1 may play a key role in accelerating the development of EMS via enhancing the secretion of proinflammatory factors and promoting angiogenesis.

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Min Yu, Xiandong Peng, He Li, Yining Xu, Xiaoxi Sun, and Jiazhou Chen

Embryo implantation, a critical step during the mammalian reproductive process, requires normal developing blastocysts and a receptive endometrium. Endometriosis, a common pathologically benign gynecological condition, is associated with decreased fertility and reduced endometrial receptivity. The oncoprotein, Gankyrin, has been associated with endometriosis and endometrial cancer. Here, we examined the role of Gankyrin during the process of embryo implantation. We found that Gankyrin expression levels were significantly increased during the mid-secretory phase, but unaffected during the proliferative phase in the human endometrium. Using an in vitro cell adhesion assay to examine the cell adhesion rate of BeWo trophoblast spheroids to Gankyrin-knockdown or overexpressing human endometrial carcinoma RL95-2 cells, we demonstrated that the adhesion rate was significantly reduced in Gankyrin-knockdown RL95-2 cells, while overexpression of Gankyrin promoted cell adhesion. Furthermore, we found that downregulation of Gankyrin inhibited STAT3 activation and subsequent matrix metalloproteinase 2 (MMP2) expression, while overexpression led to STAT3 activation and MMP2 expression. In vivo, we found that Gankyrin expression was increased in the endometrium after conception, but decreased with the prolongation of gestation time in female mice. siRNA-mediated knockdown of Gankyrin in the uterine horn led to a significant reduction in the number of implanted embryos nine days post-gestation, which was associated with a decrease in p-STAT3 expression and MMP2 transcription. Taken together, our findings indicate that Gankryin has a potential role in embryo implantation via STAT3 activation.