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Isabella Silva Cassimiro, Amanda Rodrigues Cruz, Beatriz Pelegrini Bosque, Laura Calazans de Melo Gomes, Renata Graciele Zanon, Jéssica Regina da Costa Silva, Patrícia Tieme Fujimura, Carlos Ueira-Vieira and Daniele Lisboa Ribeiro

The prostate development has an important postnatal period where cell proliferation begins at the first days after birth and is related to gland growth and ramification. Any metabolic and/or hormonal changes occurring during the postnatal period can interfere with prostate branching. Hyperglycemia is a common condition in low-weight preterm babies at neonatal period and also a disorder found in the offspring of obese mothers. Thus, this study aimed to investigate the in vitro effects of a glucose-rich environment during prostate postnatal development. Wistar rats prostate were removed at birth and cultured for 1, 2 and 3 days in DMEM under normal (5.5 mM) or elevated (7 and 25 mM) glucose concentrations. Samples were processed for morphological analysis, PCNA and smooth muscle α-actin immunohistochemistry, evaluation of active caspase-3, ERK1/2 and Wnt5a gene expression. High glucose concentrations reduced the number of prostatic buds and proliferating cells. The natural increase in smooth muscle cells and collagen deposition observed in control prostates during the first 3 days of development was reduced by elevated glucose concentrations. The amount of active caspase-3 was higher in prostates incubated at 7 mM and TGF-β levels also increased sharply after both glucose concentrations. Additionally, high glucose environment decreased ERK 1/2 activation and increased Wnt5a expression. These data show that high levels of glucose during the first postnatal days affected prostate development by inhibiting cell proliferation which impairs bud branching and this was associated with anti-proliferative signals such as decreased ERK1/2 activation and increased Wnt5a expression.

Open access

Roseanne Rosario, Hazel L Stewart, Emily Walshe and Richard A Anderson

In female mammals, reproductive potential is determined during fetal life by the formation of a non-renewable pool of primordial follicles. Initiation of meiosis is one of the defining features of germ cell differentiation and is well established to commence in response to retinoic acid. WIN 18,446 inhibits the conversion of retinol to retinoic acid, and therefore it was used to explore the impact of reduced retinoic acid synthesis on meiotic progression and thus germ cell development and subsequent primordial follicle formation. e13.5 mouse fetal ovaries were cultured in vitro and treated with WIN 18,446 for the first 3 days of a total of up to 12 days. Doses as low as 0.01 µM reduced transcript levels of the retinoic acid response genes Stra8 and Rarβ without affecting germ cell number. Higher doses resulted in germ cell loss, rescued with the addition of retinoic acid. WIN 18,446 significantly accelerated the progression of prophase I; this was seen as early as 48 h post treatment using meiotic chromosome spreads and was still evident after 12 days of culture using Tra98/Msy2 immunostaining. Furthermore, ovaries treated with WIN 18,446 at e13.5 but not at P0 had a higher proportion of growing follicles compared to vehicle controls, thus showing evidence of increased follicle activation. These data therefore indicate that retinoic acid is not necessary for meiotic progression but may have a role in the regulation of its progression and germ cell survival at that time and provide evidence for a link between meiotic arrest and follicle growth initiation.

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Jian Zhang, Linlin Hao, Qian Wei, Sheng Zhang, Hui Cheng, Yanhui Zhai, Yu Jiang, Xinglan An, Ziyi Li, Xueming Zhang and Bo Tang

Somatic cell nuclear transfer (SCNT) has been successfully used for cloning in a variety of mammalian species. However, SCNT reprogramming efficiency is relatively low, in part, due to incomplete DNA methylation reprogramming of donor cell nuclei. We previously showed that ten-eleven translocation 3 (TET3) is responsible for active DNA demethylation during preimplantation embryonic development in bovines. In this study, we constructed TET3-overexpressing cell lines in vitro and observed that the use of these fibroblasts as donor cells increased the blastocyst rate by approximately 18 percentage points compared to SCNT. The overexpression of TET3 in bovine SCNT embryos caused a decrease in the global DNA methylation level of the pluripotency genes Nanog and Oct-4, ultimately resulting in an increase in the transcriptional activity of these pluripotency genes. Moreover, the quality of bovine TET3-NT embryos at the blastocyst stage was significantly improved, and bovine TET3-NT blastocysts possessed more total number of cells and fewer apoptotic cells than the SCNT blastocysts, similar to in vitro fertilization (IVF) embryos. Nevertheless, DNA methylation of the imprinting control region (ICR) for the imprinted genes H19-IGF2 in SCNT embryos remained unaffected by TET3 overexpression, maintaining parent-specific activity for further development. Thus, the results of our study provide a promising approach to rectify incomplete epigenetic reprogramming and achieve higher cloning efficiency.

Free access

Vanessa Machado, Joana Lopes, Mariana Patrão, João Botelho, Luís Proença and José João Mendes

Hormones and inflammatory mechanisms are implicated with female reproductive function, including follicle maturation, ovulation, embryo implantation, and pregnancy. Periodontitis is a chronic inflammatory disease due to a polymicrobial disruption of the homeostasis and may be considered as a potential risk factor that affect female fertility. The role of periodontitis is becoming meaningful, with significant associations with polycystic ovary syndrome, endometriosis and bacterial vaginosis. Further, periodontitis is linked with known risk factors towards female infertility, such as age, obesity, and chronic kidney disease. This review aims to summarize the available evidence on the association between periodontitis and female infertility-associated conditions, and to discuss warranting steps in future research.

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Cheng Zeng, Pei-Li Wu, Zhao-Tong Dong, Xin Li, Ying-Fang Zhou and Qing Xue

Endometriosis is an estrogen-dependent disease, and estrogen receptor 2 (ESR2) plays a critical role in the pathogenesis of ovarian endometriosis by promoting cell invasion. Yes-associated protein 1 (YAP1) plays suppressive roles in several types of tumors. However, the relationship between YAP1 and ESR2 is not fully understood. The aim of this study was to investigate the regulatory mechanism of YAP1 in terms of ESR2 and YAP1 regulation of endometriotic stromal cell (ECSC) invasion in ovarian endometriosis. Our results demonstrated that YAP1 mRNA and protein levels in eutopic endometrium (EU) tissues were higher than those in paired ectopic endometrium (EC) tissues. ECSCs transfected with siYAP1 exhibited a significant increase in both ESR2 mRNA levels and protein expression. Simultaneously, YAP1 overexpression in ECSCs yielded the opposite results. Co-IP assays demonstrated YAP1-NuRD complex formation by YAP1, CHD4 and MTA1 in ECSCs. YAP1 bound to two sites, (-539, -533) and (-158, -152), upstream of the ESR2 transcription initiation site. YAP1 binding to the two sites of the ESR2 promoter in ECSCs was significantly lower than that in eutopic endometrial stromal cells (EUSCs) from EU tissues. ECSCs transfected with siYAP1 exhibited increased invasion activity, while ECSCs transfected with siESR2 showed inhibition of invasion. However, transfection with siYAP1 and siESR2 together decreased the number of invading cells compared with transfection with siYAP1 alone. Therefore, we conclude that decreased levels of YAP1 in ovarian endometriomas enhance ESR2 expression via formation of a YAP1-NuRD complex, which further binds to the ESR2 promoters. Furthermore, YAP1 inhibits ECSCs invasion.

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Cuihong Zheng, Thippeswamy Gulappa, Bindu Menon and K M J Menon

Ovarian hyperstimulation syndrome (OHSS) is a common complication of ovarian stimulation associated with the administration of human chorionic gonadotropin (hCG) during assisted reproduction. We have determined the expression of luteinizing hormone receptor (Lhcgr) mRNA, vascular endothelial growth factor (VEGF), and its transcription factor, HIF1α, during the periovulatory period in a rodent model of OHSS and compared these results with normal ovulatory periods. These results showed that the downregulation of Lhcgr mRNA in response to conditions that mimic preovulatory LH surge was significantly impaired in the OHSS group compared to the complete downregulation seen in the control group. Most importantly, the downregulation of luteinizing hormone receptor mRNA expression following hCG administration was sustained in the control group up to 48 h, whereas it remained at significantly higher levels in the OHSS group. This impairment of hCG-induced Lhcgr downregulation in the OHSS group was accompanied by significantly elevated levels of VEGF and its transcription factor, HIF1α. Furthermore, the downregulation of Lhcgr that occurs in response to a preovulatory LH surge in normal cycles was accompanied by low levels of VEGF. This study shows that, while downregulation of Lhcgr as well as low VEGF levels are seen in response to a preovulatory LH surge in normal ovarian cycle, impaired Lhcgr downregulation and elevated VEGF levels were found in the OHSS group.

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Naoki Hirose, Sayaka Wakayama, Rei Inoue, Junya Ito, Masatoshi Ooga and Teruhiko Wakayama

Artificial oocyte activation is important for assisted reproductive technologies, such as fertilization with round spermatids (ROSI) or the production of cloned offspring by somatic cell nuclear transfer (SCNT). Recently, phospholipase Cζ (PLCζ)-cRNA was used to mimic the natural process of fertilization, but this method required the serial injection of PLCζ-cRNA and was found to cause damage to the manipulated oocytes. Here we tried to generate offspring derived from oocytes that were fertilized using round spermatid or somatic cell nuclear transfer with the co-injection of PLCζ-cRNA. After co-injecting round spermatids and 20 ng/µL of PLCζ-cRNA into the oocytes, most of them became activated, but the activation process was delayed by more than 1 h. With the co-injection method, the rate of blastocyst formation in ROSI embryos was higher (64%) compared with that of the serial injection method (55%). On another note, when SCNT was performed using the co-injection method, the cloned offspring were obtained with a higher success rate compared with the serial-injection method. However, in either ROSI or SCNT embryos, the birth rate of offspring via the co-injection method was similar to the Sr activation method. The epigenetic status of ROSI and SCNT zygotes that was examined showed no significant difference among all activation methods. The results indicated that although the PLCζ-cRNA co-injection method did not improve the production rate of offspring, this method simplified oocyte activation with less damage, and with accurate activation time in individual oocytes, it can be useful for the basic study of oocyte activation and development.

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Leyla Sati

The circadian system regulates the daily temporal organization in behavior and physiology, including neuroendocrine rhythms and reproduction. Modern life, however, increasingly impacts this complex biological system. Due to limitations of working with human subjects exposed to shiftwork schedules, most chronoregulation research has used rodent models. Recent publications in these model systems have emphasized the negative effects of circadian rhythm disruption on both female and male reproductive systems and fertility. Additionally, there is growing concern about the long-term effects of circadian rhythm disruptions during pregnancy on human offspring and their descendants as circadian regulation during pregnancy can also alter epigenetic programing in offspring. However, to truly know if such concerns apply to humans will require retrospective and prospective human studies. Therefore, this review will highlight the latest available evidence regarding potential effects of chronodisruption on both female and male reproductive systems. Additionally, it presents a comprehensive summary of transgenerational and epigenetic effects on adult offspring that result from maternal chronodisruption.

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Alisa Komsky-Elbaz, Dorit Kalo and Zvi Roth

This study aims to evaluate the deleterious effect of the mycotoxin aflatoxin B1 (AFB1) on bull spermatozoa and the carry-over effect on the developing embryo. Proteomic analysis of AFB1-treated spermatozoa revealed differential expression of proteins associated with biological processes and cellular pathways that involved in spermatozoon function, fertilization competence and embryonic development. Therefore, we assume that factors delivered by the spermatozoa, regardless DNA fragmentation, are also involved. To confirm this hypothesis, we have used the annexin V (AV) kit to separate the spermatozoa into apoptotic (AV+) and non-apoptotic (AV-) subpopulations which were found to correlate with high- and low DNA fragmentation, respectively. Fertilization with AV+ AFB1-treated spermatozoa, resulted in no blastocyst formation, whereas fertilization with AV- spermatozoa resulted in reduced cleavage rate and formation of genetically altered blastocysts (POU5F1 and SOX2). Microarray analysis of blastocysts derived from 10 µM AFB1-treated spermatozoa revealed differential expression of 345 genes that involved in cellular pathways such as embryo and placenta development, cell cycle, DNA repair and histone modification, and in signaling pathways, especially calcium signaling pathway. This is the first report on deleterious carrying over effects of AFB1 from the bovine spermatozoa to the formed embryo. Our findings suggest that aside from the damage caused by AFB1 to spermatozoa's DNA integrity, additional damage mechanisms are involved.

Open access

Marta Almada, Lia Costa, Bruno Fonseca, Patrícia Alves, Jorge Braga, Daniela Gonçalves, Natércia Teixeira and Georgina Correia-da-Silva

Proliferation, differentiation and apoptosis of trophoblast cells are required for normal placental development. Impairment of those processes may lead to pregnancy-related diseases. Disruption of endoplasmic reticulum (ER) homeostasis has been associated with several reproductive pathologies including recurrent pregnancy loss and preeclampsia. In the unfolded protein response (UPR), specific ER-stress signalling pathways are activated to restore ER homeostasis, but if the adaptive response fails, apoptosis is triggered. Protein kinase RNA-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1 (IRE1) and Activating transcription factor 6 (ATF6) are central players in UPR and in ER-stress-induced apoptosis, as well as downstream transcription factors, as C/EBP homologous protein (CHOP). Our previous studies have shown that the endocannabinoid 2-arachidonoylglycerol (2-AG) modulates trophoblast cell turnover. Nevertheless, the role of ER-stress on 2-AG induced apoptosis and cannabinoid signalling in trophoblast has never been addressed. In this work, we used BeWo cells and human primary cytotrophoblasts isolated from term-placenta. The expression of ER-stress markers was analysed by qRT-PCR and Western blotting. ROS generation was assessed by fluorometric methods, while apoptosis was detected by the evaluation of caspase -3/-7 activities and Poly (ADP-ribose) polymerase (PARP) cleavage. Our findings indicate that 2-AG is able to induce ER-stress and apoptosis. Moreover, the eukaryotic initiation factor 2 (eIF2α)/CHOP pathway involved in ER-stress-induced apoptosis is triggered through a mechanism dependent on cannabinoid receptor CB2 activation. The results bring novel insights on the importance of ER-stress and cannabinoid signalling on 2-AG mechanisms of action in placenta.