Yan-Ting Wu

Insufficient maintenance DNA methylation is associated with abnormal embryonic development

BackgroundEarly pregnancy loss (EPL) is a frustrating clinical problem, whose mechanisms are not completely understood. DNA methylation, which includes maintenance methylation and de novo methylation directed by DNA methyltransferases (DNMTs), is important for embryo development. Abnormal function of these DNMTs may have serious consequences for embryonic development.MethodsTo evaluate the possible involvement of DNA methylation in human EPL, the expression of DNMT proteins and global methylation of DNA were assessed in villous or decidua from EPL patients. The association of maintenance methylation with embryo implantation and development was also examined.ResultsWe found that DNMT1 and DNMT3A were both expressed in normal human villous and decidua. DNMT1 expression and DNA global methylation levels were significantly down-regulated in villous of EPL. DNMT3A expression was not significantly changed in the EPL group compared to controls in either villous or decidua. We also found that disturbance of maintenance methylation with a DNMT1 inhibitor may result in a decreased global DNA methylation level and impaired embryonic development in the mouse model, and inhibit in vitro embryo attachment to endometrial cells.ConclusionsOur results demonstrate that defects in DNA maintenance methylation in the embryo, not in the mother, are associated with abnormal embryonic implantation and development. The findings of the current study provide new insights into the etiology of EPL.

Comparative proteomic analysis of human placenta derived from assisted reproductive technology

The aim of this study was to use proteomics‐based approach to examine differences in protein expression in placenta derived from assisted reproductive technology (ART) and normal pregnancy. Using 2‐DE we found that, compared with the control group, 12 spots in standard in vitro fertilization group and 18 spots in intracytoplasmic sperm injection group were identified as significantly differentially expressed proteins. Among them, six spots were differentially expressed in both standard IVF and ICSI groups with the same change tendency. Totally, 20 proteins were successfully identified by MALDI TOF/TOF MS, including proteins involved in the membrane traffic, metabolism, nucleic acid processing, stress response and cytoskeleton. Notably, five proteins detected to be differentially expressed in both ART groups were identified as annexin A3, hnRNP C1/C2, α‐SNAP, FTL and ATP5A. Some of the proteins were confirmed by Western blot and immunohistochemistry analysis. Our study allowed for the initial identification of these proteins related to various functions in placentation with significantly altered abundance in ART groups. The present results reveal that abnormal protein profiles are involved in ART placenta and these differentially expressed proteins may be valuable for the evaluation of potential association between ART treatment and offspring outcome.

FSH regulates fat accumulation and redistribution in aging through the Gαi/Ca2+/CREB pathway

Increased fat mass and fat redistribution are commonly observed in aging populations worldwide. Although decreased circulating levels of sex hormones, androgens and oestrogens have been observed, the exact mechanism of fat accumulation and redistribution during aging remains obscure. In this study, the receptor of follicle‐stimulating hormone (FSH), a gonadotropin that increases sharply and persistently with aging in both males and females, is functionally expressed in human and mouse fat tissues and adipocytes. Follicle‐stimulating hormone was found to promote lipid biosynthesis and lipid droplet formation; FSH could also alter the secretion of leptin and adiponectin, but not hyperplasia, in vitro and in vivo. The effects of FSH are mediated by FSH receptors coupled to the Gαi protein; as a result, Ca2+ influx is stimulated, cAMP‐response‐element‐binding protein is phosphorylated, and an array of genes involved in lipid biosynthesis is activated. The present findings depict the potential of FSH receptor‐mediated lipodystrophy of adipose tissues in aging. Our results also reveal the mechanism of fat accumulation and redistribution during aging of males and females.

Adriamycin induces H2AX phosphorylation in human spermatozoa

AIM To investigate whether adriamycin induces DNA damage and the formation of gammaH2AX (the phosphorylated form of histone H2AX) foci in mature spermatozoa. METHODS Human spermatozoa were treated with adriamycin at different concentrations. gammaH2AX was analyzed by immunofluorescent staining and flow cytometry and double-strand breaks (DSB) were detected by the comet assay. RESULTS The neutral comet assay revealed that the treatment with adriamycin at 2 microg/mL for different times (0.5, 2, 8 and 24 h), or for 8 h at different concentrations (0.4, 2 and 10 microg/mL), induced significant DSB in spermatozoa. Immunofluorent staining and flow cytometry showed that the expression of gH2AX was increased in a dose-dependent and time-dependant manner after the treatment of adriamycin. Adriamycin also induced the concurrent appearance of DNA maintenance/repair proteins RAD50 and 53BP1 with gammaH2AX in spermatozoa. Wortmannin, an inhibitor of the phosphatidylinositol 3-kinase (PI3K) family, abolished the co-appearance of these two proteins with gammaH2AX. CONCLUSION Human mature spermatozoa have the same response to DSB-induced H2AX phosphorylation and subsequent recruitment of DNA maintenance/repair proteins as somatic cells.

Identification of a mutation in GDF9 as a novel cause of diminished ovarian reserve in young women

STUDY QUESTION Do any mutations in growth differentiation factor 9 (GDF9) have a role in diminished ovarian reserve (DOR) in young women? SUMMARY ANSWER The GDF9 p.R146C mutation may be a source of DOR in some young women. WHAT IS KNOWN ALREADY DOR affects 10% of women under 37 years of age and is associated with accelerated expenditure of follicles. GDF9 is an oocyte-secreted factor that plays a critical role in follicular development and female fertility. Several GDF9 variants have been linked to ovarian dysfunction. STUDY DESIGN, SIZE, DURATION This case-control study included 139 women with DOR and 152 controls aged under 37 years. PARTICIPANTS/MATERIALS, SETTING, METHODS All women were recruited in a Chinese tertiary center and underwent DNA sequencing of GDF9 gene. We then determined the molecular and biological properties of mutant GDF9 proteins using protein expression, structural prediction and functional analyses. MAIN RESULTS AND THE ROLE OF CHANCE We identified two mutations in the proregion of GDF9 gene: c.169T > G (p.D57Y) and c.436T > C (p.R146C). The p.R146C mutation was found in three women with DOR but was absent in the control population. This mutation was also associated with significant reductions in GDF9 mature protein secretion in cultured cells. Functional studies with human granulosa cells (GCs) showed that the p.R146C mutation reduced the abilities of GDF9 to stimulate GC proliferation and to activate the Smad2 pathway. Protein structure modeling predicted that p.R146C disrupted an α-helix in GDF9 protein. In contrast with p.R146C, the p.D57Y mutation, found in both the DOR and control groups (6 versus 2), had no obvious deleterious effects. LIMITATIONS, REASONS FOR CAUTION Larger studies in varying populations may validate the role of GDF9 mutation in young women with DOR. WIDER IMPLICATIONS OF THE FINDINGS These results may provide new insights into the pathophysiological mechanisms of early-onset DOR.

Bone morphogenetic protein-15 in follicle fluid combined with age may differentiate between successful and unsuccessful poor ovarian responders.

BackgroundThe counselling of poor ovarian responders about the probability of pregnancy remains a puzzle for gynaecologists. The aim of this study was to optimise the management of poor responders by investigating the role of the oocyte-derived factor bone morphogenetic protein-15 (BMP-15) combined with chronological age in the prediction of the outcome of in-vitro fertilisation-embryo transfer (IVF-ET) in poor responders.MethodsA retrospective study conducted in a university hospital. A total of 207 poor ovarian responders who reached the ovum pick-up stage undergoing IVF/intracytoplasmic sperm injection (ICSI) with three or fewer follicles no less than 14 mm on the day of oocyte retrieval were recruited from July 1, 2008 to December 31, 2009. Another 215 coinstantaneous cycles with normal responses were selected as controls. The BMP-15 levels in the follicular fluid (FF) of the 207 poor responders were analysed by western blot. Based on the FF BMP-15 level and age, poor responders were sub-divided into four groups. The main outcome measures were the FF BMP-15 level, implantation rate, pregnancy rate, and live birth rate.ResultsThe implantation rate (24.2% vs. 15.3%), chemical pregnancy rate (40% vs. 23.7%), clinical pregnancy rate (36.5% vs. 20.4%) and live birth rate (29.4% vs. 15.1%) in the high BMP-15 group were significantly higher than those in the low BMP-15 group. Furthermore, poor responders aged less than or equal to 35 years with a higher FF BMP-15 level had the best implantation, pregnancy and live birth rates, which were comparable with those of normal responders.ConclusionsOur study suggests a potential role of BMP-15 in the prediction of the IVF outcome. A high FF BMP-15 combined with an age less than or equal to 35 years may be used as a potential indicator for repeating IVF cycles in poor ovarian responders.

High expression levels of cyclin B1 and Polo-like kinase 1 in ectopic endometrial cells associated with abnormal cell cycle regulation of endometriosis

OBJECTIVE To investigate the possible roles of cyclin B1/cyclin-dependent kinase (cdc2) and Polo-like kinase 1 (Plk1) in the pathogenesis of endometriosis. DESIGN A case-control study. SETTING University hospital. PATIENT(S) Patients with or without endometriosis were diagnosed by pathological examination or laparoscopy. The patients with the following criteria within the past 6 months were excluded: endocrine or inflammatory diseases, pregnancy or lactation, hormonal therapy, and neoplasm in the uterine cavity. INTERVENTION(S) Eutopic and ectopic endometria were obtained at the time of surgery. Blood was collected on the same day as surgery. MAIN OUTCOME MEASURE(S) The mRNA/protein expression and localization of cyclin B1, cdc2, and Plk1 in endometrium, and serum levels of E(2) and P. RESULT(S) The expression levels of cyclin B1 and Plk1, but not cdc2, in ectopic endometria were significantly higher than in eutopic endometria. The immunohistochemical staining of cyclin B1 and Plk1 was detected in the nuclei of ectopic and eutopic endometrial cells. Furthermore, ectopic endometrial expression levels of cyclin B1 or Plk1 were positively correlated with serum E(2) levels. CONCLUSION(S) Cyclin B1 and Plk1 may play important roles in the pathogenesis of endometriosis by mediating ectopic endometrial cell proliferation under regulation of ovarian hormones.

G546A polymorphism of growth differentiation factor-9 contributes to the poor outcome of ovarian stimulation in women with diminished ovarian reserve

The growth differential factor-9 (GDF-9) gene, an oocyte-specific factor, was screened in 106 Chinese women with diminished ovarian reserve (DOR), and three single-nucleotide polymorphisms, c.G169A, c.C447T and c.G546A, were detected. We found GDF-9 c.G546A, but not c.G169A or c.C447T, to be correlated with the poor ovarian stimulation and in vitro fertilization outcomes in women with DOR.

Preliminary proteomic analysis on the alterations in follicular fluid proteins from women undergoing natural cycles or controlled ovarian hyperstimulation.

PurposeTo study the differences in protein expression profiles of follicular fluid (FF) between controlled ovarian hyperstimulation (COH) and natural ovulatory cycles.MethodsTwelve infertile women undergoing in vitro fertilization and embryo transfer (IVF–ET), with matched clinical information, were retrospectively recruited in the IVF center of our university hospital, including six undergoing COH and another six with natural cycles. FF was sampled from dominant follicles with mature oocytes. Protein expression profiles in each FF sample were analyzed respectively using two-dimensional gel electrophoresis. Differentially expressed proteins were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and validated by western blotting. Differentially expressed proteins were further analyzed using Ingenuity Pathway Analysis (IPA) software.ResultsTwo proteins were downregulated and 11 proteins were upregulated (change ≥1.5-fold, P < 0.05) in the COH group. We identified one down-egulated and seven upregulated proteins using MALDI-TOF MS. Four differentially expressed proteins, including transferrin, complement component C3 (C3), haptoglobin and alpha-1-antitrypsin (AAT), were further validated by rate nephelometry and western blotting analyses. The IPA analysis revealed a significant network involved in the humoral immune and inflammatory responses.ConclusionsThe eight differentially expressed proteins were related to immune and inflammatory responses in the ovary. Our results provide new insights into the influence of COH on follicular (spp) development and IVF outcomes.

Altered DNA methylation in neonates born large-for-gestational-age is associated with cardiometabolic risk in children

Background Infants being born Large-for-gestational-age (LGA) are prone to developing cardiometabolic disease. However, the underlying mechanisms remain unclear. Results Clinical investigation showed that children born LGA had significantly higher serum level of total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-c), and insulin, ratio of TC/high-density lipoprotein-cholesterol (HDL-c) compared to children born appropriate for gestational age (AGA). Birth weight (BW) was positively correlated to TC, LDL-c, and the ratio of TC/HDL in serum. Genome-wide DNA methylation analyzed in umbilical cord blood of controls and macrosomia cases. We identified 3459 methylation variable positions (MVPs) achieving genome-wide significance (adjusted P-value < 0.05) with methylation differences of ≥ 5%. A total of 327 MVPs were filtered by methylation differences of ≥ 7% located within an island, which mapped to 213 genes. Function analysis using Ingenuity Pathway Analysis showed 16 genes enriched in “cardiovascular disease”. Four genes included contributed to hyperlipidemia. Materials And Methods Fifty-eight children aged 3–6 years born LGA and 123 subjects born AGA were enrolled. Anthropometric parameters and blood pressure (BP) were measured, and metabolic assessment was performed in all subjects. Genome-wide DNA methylation in umbilical blood was assayed by the 450K BeadChip in six AGA and six macrosomia newborns. Conclusions Our data indicate that excess birth weight may increase the risk of lipid dysfunction in children aged 3–6 years. It might through reprogramming a group of genes correlated to cardiovascular disease. The genes identified in this study might be potential biomarker for cardiometabolic disease.