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Chen C.-L.,Qingdao Agricultural University | Fu X.-F.,Qingdao Agricultural University | Wang L.-Q.,Qingdao Agricultural University | Wang J.-J.,Qingdao Agricultural University | And 7 more authors.
Molecular Biology Reports | Year: 2014

Notch signaling pathway, a highly conserved cell signaling system, exists in most multicellular organisms. The objective of this study was to examine Notch signaling pathway in germ cell cyst breakdown and primordial follicle formation. The receptor and ligand genes of Notch pathway (Notch1, Notch2, Jagged1, Jagged2 and Hes1) were extremely down-regulated after newborn mouse ovaries were cultured then exposed to DAPT or L-685,458 in vitro (P < 0.01). Since DAPT or L-685,548 inhibits Notch signaling pathway, the expression of protein LHX8 and NOBOX was significantly reduced during the formation of the primordial follicles. Down-regulated mRNA expression of specific genes including Lhx8, Figla, Sohlh2 and Nobox, were also observed. The percentages of female germ cells in germ cell cysts and primordial follicles were counted after culture of newborn ovaries for 3 days in vitro. The result showed female germ cells in cysts was remarkably up-regulated while as the oocytes in primordial follicles was significantly down-regulated (P < 0.05). In conclusion, Notch signaling pathway may regulate the formation of primordial follicle in mice. © 2014 Springer Science+Business Media. Source

Broer S.L.,University Utrecht | Broer S.L.,Amsterdam Medical Center | van Disseldorp J.,University Utrecht | van Disseldorp J.,Amsterdam Medical Center | And 41 more authors.
Human Reproduction Update | Year: 2013

Background: Although ovarian reserve tests (ORTs) are frequently used prior to IVF treatment for outcome prediction, their added predictive value is unclear. We assessed the added value of ORTs to patient characteristics in the prediction of IVF outcome. Methods: An individual patient data (IPD) meta-analysis from published studies was performed. Studies on FSH, anti-Müllerian hormone (AMH) or antral follicle count (AFC) in women undergoing IVF were identified and authors were contacted. Using random intercept logistic regression models, we estimated the added predictive value of ORTs for poor response and ongoing pregnancy after IVF, relative to patient characteristics. Results: We were able to collect 28 study databases, comprising 5705 women undergoing IVF. The area under the receiver-operating characteristic curve (AUC) for female age in predicting poor response was 0.61. AFC and AMH each significantly improved the model fit (P-value <0.001). Moreover, almost a similar accuracy was reached using AMH or AFC alone (AUC 0.78 and 0.76, respectively). Combining the two tests, however, did not improve prediction (AUC 0.80, P = 0.19) of poor response. In predicting ongoing pregnancy after IVF, age was the best single predictor (AUC 0.57), and none of the ORTs added any value. Conclusions: This IPD meta-analysis demonstrates that AFC and AMH clearly add to age in predicting poor response. As single tests, AFC and AMH both fully cover the prediction of poor ovarian response. In contrast, none of the ORTs add any information to the limited capacity of female age to predict ongoing pregnancy after IVF. The clinical usefulness of ORTs prior to IVF will be limited to the prediction of ovarian response. © The Author 2012. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. Source

Haque M.M.,Center for Reproductive Biology | Nilsson E.E.,Center for Reproductive Biology | Skinner M.K.,Center for Reproductive Biology
BMC Genomics | Year: 2016

Background: A variety of environmental factors have been shown to promote the epigenetic transgenerational inheritance of disease and phenotypic variation in numerous species. Exposure to environmental factors such as toxicants can promote epigenetic changes (epimutations) involving alterations in DNA methylation to produce specific differential DNA methylation regions (DMRs). The germline (e.g. sperm) transmission of epimutations is associated with epigenetic transgenerational inheritance phenomena. The current study was designed to determine the genomic locations of environmentally induced transgenerational DMRs and assess their potential clustering. Results: The exposure specific DMRs (epimutations) from a number of different studies were used. The clustering approach identified areas of the genome that have statistically significant over represented numbers of epimutations. The location of DMR clusters was compared to the gene clusters of differentially expressed genes found in tissues and cells associated with the transgenerational inheritance of disease. Such gene clusters, termed epigenetic control regions (ECRs), have been previously suggested to regulate gene expression in regions spanning up to 2-5 million bases. DMR clusters were often found to associate with inherent gene clusters within the genome. Conclusion: The current study used a number of epigenetic datasets from previous studies to identify novel DMR clusters across the genome. Observations suggest these clustered DMR within an ECR may be susceptible to epigenetic reprogramming and dramatically influence genome activity. © 2016 The Author(s). Source

Zhang L.-J.,Qingdao Agricultural University | Chen B.,Qingdao Agricultural University | Feng X.-L.,Qingdao Agricultural University | Ma H.-G.,Center for Reproductive Biology | And 6 more authors.
Reproduction, Fertility and Development | Year: 2015

In mammals, ontogenesis starts from a fusion of spermatozoon and oocyte, which are produced by reductive nuclear division of a diploid germ cell in a specialised but complex biological process known as meiosis. However, little is known about the mechanism of meiotic initiation in germ cells, although many factors may be responsible for meiosis both in male and female gonads. In this study, 11.5 days post coitum (dpc) female fetal mouse genital ridges were cultured in vitro with exposure to Brefeldin A (BFA) for 6h, and the changes in meiosis were detected. Synaptonemal-complex analysis implied that BFA played a positive role in meiosis initiation and this hypothesis was confirmed by quantitative PCR of meiosis-specific genes: stimulated by retinoic acid gene 8 (Stra8) and deleted in a zoospermia-like (DAZL). At the same time, mRNA expression of retinoic acid synthetase (Raldh2) and retinoic acid (RA) receptors increased in female gonads with in vitro exposure to BFA. Transplanting genital ridges treated with BFA into the kidney capsule of immunodeficient mice demonstrated that the development capacity of female germ cells was normal, while formation of primordial follicles was seen to be a result of accelerated meiosis after exposure to BFA. In conclusion, the study indicated that BFA stimulated meiosis initiation partly by RA signalling and then promoted the development of follicles. © 2015 CSIRO. Source

Li L.,Qingdao Agricultural University | Li L.,Northwest University, China | Zhang T.,Qingdao Agricultural University | Qin X.-S.,Qingdao Agricultural University | And 9 more authors.
Molecular Biology Reports | Year: 2014

Diethylhexyl phthalate (DEHP) is an estrogen-like compound widely used as a plasticizer in commercial products and is present in medical devices, and common household items. It is considered an endocrine disruptor since studies on experimental animals clearly show that exposure to DEHP can alter epigenetics of germ cells. This study was designed to assess the effects of DEHP on DNA methylation of imprinting genes in germ cells from fetal and adult mouse. Pregnant mice were treated with DEHP at doses of 0 and 40 μg DEHP/kg body weight/day from 0.5 to 18.5 day post coitum. The data revealed DEHP exposure significantly reduced the percentage of methylated CpG sites in Igf2r and Peg3 differentially methylated regions (DMRs) in primordial germ cells from female and male fetal mouse, particularly, in the oocytes of 21 dpp mice (F1), which were produced by the pregnant micetreated with DEHP. More surprisingly, the modification of the DNA methylation of imprinted genes in F1 mouse oocytes was heritable to F2 offspring which exhibit lower percentages of methylated CpG sites in imprinted genes DMRs. In conclusion, DEHP exposure can affect the DNA methylation of imprinting genes not only in fetal mouse germ cells and growing oocytes, but also in offspring's oocytes. © 2014 Springer Science+Business Media. Source

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