Neonatal exposure of bisphenol A led to increased lipolysis of visceral adipose tissue in adult rats with DNA hypomethylation of Atgl being one of the possible underlying mechanisms.

Accumulating evidence suggests the role of developmental exposure of bisphenol A (BPA) in metabolic disorders. However, the underlying mechanism remains unclear. Using a rat model, we investigated the neonatal exposure of BPA on lipid metabolism in adult and the underlying mechanisms. From postnatal day1(PND1) to PND10, male rats were exposed to BPA via daily subcutaneous injection with 10 µg/100 µL BPA (1.24-0.5 mg/kg body weight/day, a dose below the US-EPA LOAEL). After fasting for 8 h, adult rats aged 80 days showed elevated levels of serum free fatty acid (FFA), glycerol and glucose, and increased levels of FFA and glycerol in visceral adipose tissue. The expression levels of key enzymes of lipolysis, adipose triglyceride lipase (Atgl) and hormone-sensitive lipase (Hsl), were increased in visceral adipose tissue from BPA-exposed rats after fasting. On the other hand, transcription levels of lipogenic genes remained unchanged. Differentiation of visceral adipocyte in rats takes place neonatally. In our study, neonatal BPA exposure induced DNA hypomethylation of Atgl in visceral adipose tissue. In 3T3-L1 cell, administration of 10-7 mol/L BPA throughout the differentiation stage led to DNA hypomethylation and increased expression of Atgl. Our results suggest that neonatal exposure of BPA led to increased lipolysis of visceral adipose tissue in young adults, which will predispose individuals to multiple metabolic disorders. The DNA hypomethylation of Atgl might be one of the mechanisms underneath the long-lasting effect of neonatal BPA exposure.

Hypertriglyceridemia in female rats during pregnancy induces obesity in male offspring via altering hypothalamic leptin signaling.

Maternal obesity influence the child's long-term development and health. Though, the mechanism concerned in this process is still uncertain. In the present study, we explored whether overfeeding of a high-fat diet during pregnancy in female rats altered metabolic phenotypes in an F1 generation and authenticated the contribution of hypothalamic leptin signaling. Leptin responsiveness and the number of immunopositive neurons for phosphorylated signal transducer and activator transcription 3 (pSTAT3) were analyzed. Neuropeptide Y in the arcuate nucleus of the hypothalamus and in nucleus tractus solitaries was examined. Triglycerides and leptin levels were increased in the high-fat diet mother. The number of neuropeptide Y positive cell bodies and neurons was significantly increased in the high-fat diet-F1 offspring (HDF-F1) as compared to Chow-F1. Leptin administration significantly decreased the food intake and increased the pSTAT3 expression levels in neurons in the arcuate nucleus of Chow-F1. However, leptin did not show any effect on food intake and had a reduced effect on pSTAT3 expression levels in neurons in the arcuate nucleus of HDF-F1. From the present domino effect, we conclude that mothers exposed to high-fat diet during pregnancy may pass the obese phenotype to the succeeding generation via altering hypothalamic leptin signaling.

Serum estradiol levels in controlled ovarian stimulation directly affect the endometrium.

Previous studies have shown that increasing estradiol concentrations had a toxic effect on the embryo and were deleterious to embryo adhesion. In this study, we evaluated the physiological impact of estradiol concentrations on endometrial cells to reveal that serum estradiol levels probably targeted the endometrium in controlled ovarian hyperstimulation (COH) protocols. An attachment model of human choriocarcinoma (JAr) cell spheroids to receptive-phase endometrial epithelial cells and Ishikawa cells treated with different estradiol (10-9 M or 10-7 M) concentrations was developed. Differentially expressed protein profiling of the Ishikawa cells was performed by proteomic analysis. Estradiol at 10-7 M demonstrated a high attachment rate of JAr spheroids to the endometrial cell monolayers. Using iTRAQ coupled with LC-MS/MS, we identified 45 differentially expressed proteins containing 43 significantly upregulated and 2 downregulated proteins in Ishikawa cells treated with 10-7 M estradiol. Differential expression of C3, plasminogen and kininogen-1 by Western blot confirmed the proteomic results. C3, plasminogen and kininogen-1 localization in human receptive endometrial luminal epithelium highlighted the key proteins as possible targets for endometrial receptivity and interception. Ingenuity pathway analysis of differentially expressed proteins exhibited a variety of signaling pathways, including LXR/RXR activation pathway and acute-phase response signaling and upstream regulators (TNF, IL6, Hmgn3 and miR-140-3p) associated with endometrial receptivity. The observed estrogenic effect on differential proteome dynamics in Ishikawa cells indicates that the human endometrium is the probable target for serum estradiol levels in COH cycles. The findings are also important for future functional studies with the identified proteins that may influence embryo implantation.

Bisphenol A Exposure May Induce Hepatic Lipid Accumulation via Reprogramming the DNA Methylation Patterns of Genes Involved in Lipid Metabolism.

Accumulating evidence suggests a role of bisphenol A (BPA) in metabolic disorders. However, the underlying mechanism is still unclear. Using a mouse BPA exposure model, we investigated the effects of long-term BPA exposure on lipid metabolism and the underlying mechanisms. The male mice exposed to BPA (0.5 µg BPA /kg/day, a human relevant dose) for 10 months exhibited significant hepatic accumulation of triglycerides and cholesterol. The liver cells from the BPA-exposed mice showed significantly increased expression levels of the genes related to lipid synthesis. These liver cells showed decreased DNA methylation levels of Srebf1 and Srebf2, and increased expression levels of Srebf1 and Srebf2 that may upregulate the genes related to lipid synthesis. The expression levels of DNA methyltransferases were decreased in BPA-exposed mouse liver. Hepa1-6 cell line treated with BPA showed decreased expression levels of DNA methyltransferases and increased expression levels of genes involved in lipid synthesis. DNA methyltransferase knockdown in Hepa1-6 led to hypo-methylation and increased expression levels of genes involved in lipid synthesis. Our results suggest that long-term BPA exposure could induce hepatic lipid accumulation, which may be due to the epigenetic reprogramming of the genes involved in lipid metabolism, such as the alterations of DNA methylation patterns.

Androgens as double-edged swords: Induction and suppression of follicular development.

Androgens, which are mediated via the androgen receptor (AR), play important roles in normal follicular development and female fertility. However, just like a double-edged sword, besides the positive effects of androgen on follicular development, abnormal androgen levels, especially as in hyperandrogenism, seriously suppress normal follicular development. A crucial balance exists between the importance of androgens in follicular development and their negative effects when in excess. As the first meiotic division and epigenetic reprogramming are two critical events in oogenesis, abnormal androgen levels or deficiency in androgen/AR signaling in the ovary may affect these vital events. Oocytes have a tendency to develop genomic instability, thus resulting in an increasing incidence of unpredictable adult diseases. Although many studies have explored the effects of androgens and AR on follicular development, the conclusions are controversial and there has been no thorough review of this topic. This review focuses on the roles of androgens in the physiological process of follicular development, summarizes new insights into the roles of androgens in the arrested development of follicles, and discusses the potential risk of adult diseases originating from abnormal follicular androgen levels or androgen receptor signals, which may determine areas for future studies.

High Maternal Serum Estradiol Levels Induce Dyslipidemia in Human Newborns via a Hepatic HMGCR Estrogen Response Element.

UNLABELLED: While the intrauterine environment is essential for the health of offspring, the impact of high maternal serum estradiol (E2) on lipid metabolism in offspring and the mechanisms are unknown. We found that ovarian stimulation (OS) could result in high E2 levels in women throughout pregnancy. Strikingly, their newborns showed elevated total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels that were positively related with E2 in newborns. In vitro, E2 dose-dependently stimulated TC and LDL-C secretion, and increased expression of the cholesterol synthesis rate-limiting enzyme 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) in HepG2 cells and mouse fetal hepatocytes. In vivo, high maternal E2 was detected and fetal livers also showed significantly higher HMGCR expression in an OS mouse model. Notably, an estrogen response element (ERE) was identified in the HMGCR promoter, indicating that high maternal serum E2 could up-regulate HMGCR expression in fetal hepatocytes via an ERE that in turn induces elevated levels of TC and LDL-C in offspring. CONCLUSION: OS can induce a high maternal E2 environment, which up-regulates HMGCR expression in fetal hepatocytes via an ERE in the promoter, and induces elevated levels of TC and LDL-C in newborns that may be related to increased risk of metabolic disease in adulthood.

Successive and cyclic oral contraceptive pill pretreatment improves IVF/ICSI outcomes of PCOS patients and ameliorates hyperandrogenism and antral follicle excess.

OBJECTIVES: To evaluate different oral contraceptive pill (OCP) pretreatment associated differential in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) outcomes of polycystic ovary syndrome (PCOS) patients and explore enhanced hormonal balance induced by the pretreatment. METHODS: This retrospective study included 500 PCOS women and 565 normal ovulating counterparts undergoing IVF/ICSI. The PCOS patients were divided into three groups based on the OCP pretreatment regimens: non-OCP (without OCP pretreatment), unsuccessive OCP (the period of successive pretreatment ≤2 months) and successive OCP (the period of successive pretreatment ≥3 months) groups. Comprehensive hormonal and ultra-sonographic assessments were performed before/after IVF pretreatment. Confounding factors affecting pregnancy outcomes were analyzed with logistic regression. RESULTS: PCOS patients with significant endocrine disorders had reduced implantation and pregnancy rates and increased miscarriage rate. Successive, not unsuccessive OCP pretreatment, significantly improved the implantation and pregnancy rates, and reduced the incidence of monotocous small-for-gestational age infants, which was accompanied by remarkably decreased hyperandrogenism and antral follicles. CONCLUSION: PCOS is an independent risk factor for poor IVF outcome. Successive, not unsuccessive, OCP cyclical pretreatment could improve pregnancy outcome of PCOS patients, associated with reduction of hyperandrogenism and antral follicle excess.

Differential proteomic analysis of umbilical artery tissue from preeclampsia patients, using iTRAQ isobaric tags and 2D nano LC-MS/MS.

Epidemiological studies suggest that the impact of preeclampsia does not only affect the mother but also the children. We know that adverse events in utero may predispose individuals to premature cardiovascular disease in adulthood, but we do not know the mechanisms. To gain insights into the mechanisms of cardiovascular dysfunction in the offspring of preeclampsia, we employed a global stable isotope labeled profiling strategy using iTRAQ reagents, followed by 2D-LC-MS/MS. We identified 1521 non-redundant proteins, and 1496 of these were quantified. Further analysis identified 53 differentially expressed proteins in umbilical artery; 22 proteins were up-regulated and 31 proteins were down-regulated. K-means clustering analysis showed that there was a specific protein expression profile in the umbilical artery which could distinguish between normal and preeclampsia patients. These 53 proteins were analyzed by Ingenuity Pathway Analysis (IPA) and were found to play important roles in the angiogenesis, vasculogenesis, and development of the cardiovascular system. In addition, the differential expression of three cardiovascular relative proteins (aldose reductase, fibronectin-1, fibrillin-1) was independently verified using western blot. These results may supply new insights into the mechanisms of vascular dysfunction in the offspring of preeclampsia patients. BIOLOGICAL SIGNIFICANCE: Increasing evidence suggests that the children who were exposed to preeclampsia in utero have an increased cardiovascular risk, and vascular dysfunction has been found in some children born of preeclampsia. However, the mechanism remains largely unknown. In this study, we identified 1521 non-redundant proteins, and 1496 of these were quantified. Further analysis identified 53 differentially expressed proteins in the umbilical artery from preeclampsia patients; 22 proteins were up-regulated and 31 proteins were down-regulated. Some of these differentially expressed proteins have been shown to play important roles in cardiovascular system development. Our results provide new insights into the potential mechanisms underlying the changed blood pressure of offspring of mothers with preeclampsia, and, the elevation of their risk of cardiovascular abnormality in later life.

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.