Jie-Xue Pan

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.

Alternative splicing of the androgen receptor in polycystic ovary syndrome

Significance Excess androgens and abnormal follicle development, largely due to ovarian granulosa cell (GC) dysfunction, characterize polycystic ovary syndrome (PCOS), a common endocrinopathy of women predisposing to infertility. Thus, it is important to understand GC dysfunction. The androgen receptor (AR) is widely believed to be an essential regulator of GC biology. High expression of AR in GCs is primarily considered to associate with PCOS. However, we show that AR alternative splice variants in GCs disturb androgen metabolism and follicle growth, leading to PCOS because of impaired transcription factor function. These data considerably change our understanding of the role of AR in the etiology of PCOS, and inform the development of clinical diagnostic and classification tests as well as novel therapeutic interventions. Polycystic ovary syndrome (PCOS) is one of the most common female endocrine disorders and a leading cause of female subfertility. The mechanism underlying the pathophysiology of PCOS remains to be illustrated. Here, we identify two alternative splice variants (ASVs) of the androgen receptor (AR), insertion and deletion isoforms, in granulosa cells (GCs) in ∼62% of patients with PCOS. AR ASVs are strongly associated with remarkable hyperandrogenism and abnormalities in folliculogenesis, and are absent from all control subjects without PCOS. Alternative splicing dramatically alters genome-wide AR recruitment and androgen-induced expression of genes related to androgen metabolism and folliculogenesis in human GCs. These findings establish alternative splicing of AR in GCs as the major pathogenic mechanism for hyperandrogenism and abnormal folliculogenesis in PCOS.

Cardiovascular Dysfunction in Offspring of Ovarian-Hyperstimulated Women and Effects of Estradiol and Progesterone: A Retrospective Cohort Study and Proteomics Analysis

CONTEXT The cardiovascular dysfunction in children born with assisted reproductive technologies has been of great concern. However, the association of ovarian hyperstimulation syndrome (OHSS), a complication of assisted reproductive technologies, with worse cardiovascular functions and underlying mechanism remains unknown. OBJECTIVES The objective of the study was to assess the cardiovascular functions of children born to mothers with OHSS and investigate the underlying regulator(s). DESIGN AND SETTING This was a retrospective cohort recruited in a university hospital. PARTICIPANTS AND METHODS We assessed the cardiovascular functions by Doppler echography in 42 children born to OHSS women, 34 children of mothers with non-OHSS in vitro fertilization, and 48 spontaneously conceived (SC) children (mean age ∼ 4.5 y). Groups were matched for gestational age at delivery and birth weight. An isobaric tag for relative and absolute quantitation-labeled proteomics analysis was performed with another set of umbilical arteries from OHSS and SC pregnancies (n = 3 for both groups). RESULTS Children of OHSS mothers showed a significantly decreased mitral ratio of early to late mitral peak velocities, reduced systolic and diastolic diameters of common carotid arteries, and impaired flow-mediated dilation compared with non-OHSS in vitro fertilization and SC children. Intima-media thickness and arterial stiffness indices were similar in the three groups. In the proteomics study, 1640 proteins were identified from OHSS and SC umbilical arteries, and 40 differentially expressed proteins were selected for further analysis. Estradiol and progesterone were identified as activated upstream regulators. CONCLUSIONS Children born to ovarian-hyperstimulated women displayed cardiovascular dysfunctions. The underlying mechanisms may involve the effects of supraphysiological estradiol and progesterone levels.

Auricular Acupressure Reduces Anxiety Levels and Improves Outcomes of in Vitro Fertilization: A Prospective, Randomized and Controlled Study

The study was to explore whether auricular acupressure (AA) can relieve anxiety during the period from trans-vaginal oocyte retrieval to the embryo transfer in IVF treatment and whether AA can improve the outcomes of IVF. 305 infertile patients with tubal blockage who were referred for IVF were included. The women were randomized into a control group with 102 cases, a Sham-AA group with 102 cases and an AA group with 101 cases. The anxiety levels were rated with Spielbergers State Trait Anxiety Inventory and the Amsterdam Preoperative Anxiety and Information Scale. Data of clinical pregnancy rate (CPR), implantation rate (IR) and live birth rate (LBR) were obtained. The levels of neuropeptide Y (NPY) and transforming growth factor alpha (TGF-alpha) in the follicular fluids were detected with ELISA. After treatment, in AA group, the levels of state anxiety, preoperative anxiety and need-for-information were significantly lower, whereas CPR, IR, LBR and NPY levels in the follicular fluids were markedly higher than Sham-AA group and control group. We concluded that AA could help to reduce anxiety levels associated with IVF and improves the outcomes of IVF partly through increasing the levels of NPY in the follicular fluids.

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.

Small-conductance calcium-activated K+ channels 3 (SK3) regulate blastocyst hatching by control of intracellular calcium concentration

BACKGROUND The present study was designed to investigate the expression of small-conductance calcium-activated K(+) channels 3 (SK3) in preimplantation embryos and to explore their role in the underlying mechanism of blastocyst hatching. METHODS Human preimplantation embryos were donated by patients who achieved successful pregnancy with in vitro fertilization. Mouse preimplantation embryos in different stages were collected and cultured with or without siRNA cell injection. The expression of SK3 was examined by RT-PCR, quantitative real-time PCR, western blot and immunofluorescence. Functional expression of SK3 was investigated using the patch-clamp technique. [Ca(2+)]i was measured by fluorescent imaging. Embryos were cultured in vitro to investigate the effect of SK3 knockdown or apamin, an SK3 inhibitor, on blastocyst hatching and F-actin formation. RESULTS In human blastocysts, the level of SK3 expression was significantly lower in blastocysts that failed to hatch than in blastocysts that hatched successfully. In mouse embryos, SK3 mRNA and protein were not found in zygotes, but were detected from the 2-cell stage onward, with the highest levels observed in blastocysts. SK3 was predominately located in the trophectoderm cell membrane of expanded blastocysts. SK3 knockdown in trophectoderm cells not only suppressed the SK3 current, but also reduced [Ca(2+)]i elevation and membrane potential hyperpolarization induced by thapsigargin. Although the formation of expanded blastocysts was not affected, blastocyst hatching and F-actin formation were significantly inhibited after SK3 knockdown in trophectoderm cells. CONCLUSIONS SK3-mediated [Ca(2+)]i elevation and membrane potential hyperpolarization in trophectoderm cells are important for blastocyst hatching, and defects in SK3 expression may contribute to infertility.

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

Abstract 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.

Adverse Intrauterine Environment and Gamete/Embryo-Fetal Origins of Diseases

The ‘fetal origins of adult disease (FOAD)’ hypothesis proposes that developmental programming during gestation may influence adult health and disease [1]. It suggests a process where events occurring at critical, or sensitive, periods of fetal development, permanently alter structure, physiology, or metabolism. These changes predispose affected individuals to diseases in later life.

Small-conductance, calcium-activated potassium channel 3 (SK3) is a modulator of endometrial remodeling during endometrial growth.

BACKGROUND Small-conductance, Ca(2+)-activated K(+) channel 3 (SK3) has been shown to be expressed in porcine endometrium. However, the roles of SK3 in human endometrium during the menstrual cycle and early pregnancy are unknown. OBJECTIVE The objective of the study was to investigate the expression and function of SK3 in human endometrium and the mechanism involved. METHODS We determined the expression of SK3 in human endometrium by RT-PCR, Western blotting, and immunofluorescence. Using electrophysiological and fluorescent imaging techniques, we investigated the effects of SK3 on the membrane potential and the concentrations of cytosolic calcium, respectively. The effects of SK3 on endometrial thickness and pregnancy outcome were also investigated. Knockdown of endometrial SK3 was used to examine the effects of SK3 on cell migration, cytoskeleton formation, and calcium concentration in the cytosol. RESULTS SK3 channels are present in human endometrium. In vivo experimental and clinical data demonstrated that the reduced expression of SK3 was associated with a thin endometrium and unsuccessful pregnancy outcomes. Knockdown of human endometrial SK3 attenuated the rise in cytosolic calcium and membrane hyperpolarization induced by thapsigargin, a Ca(2+)-ATPase inhibitor, cell migration, and F-actin assembly. Knockdown of endometrial SK3 in mice also resulted in a thin endometrium and unsuccessful pregnancy outcome. CONCLUSIONS These observations demonstrate that SK3 channels are expressed in human endometrial cells. Reduced SK3 expression attenuates endometrial cell migration and is associated with unsuccessful pregnancy outcomes.

Mechanism underlying the retarded nuclear translocation of androgen receptor splice variants

As shown in our previous study, two alternatively spliced androgen receptor (AR) variants, which are exclusively expressed in the granulosa cells of patients with polycystic ovary syndrome, exhibit retarded nuclear translocation compared with wild-type AR. However, researchers have not yet determined whether these abnormalities correlate with heat shock protein 90 (HSP90) and importin α (the former is a generally accepted co-chaperone of AR, and the latter is a component of classical nuclear import complexes). Here, these two variants were mainly retained in cytoplasm with HSP90 and importin α in the presence of dihydrotestosterone (DHT), and their levels in nucleus were significantly reduced, according to the immunofluorescence staining. The binding affinity of two AR variants for importin α was consistently decreased, while it was increased in WT-AR following DHT stimulation, leading to reduced nuclear import, particularly for the insertion-AR (Ins-AR). However, the binding affinities of two AR variants for HSP90 were increased in the absence of DHT compared with WT-AR, which functioned to maintain spatial structural stability, particularly for the deletion-AR (Del-AR). Therefore, the retarded nuclear translocation of two AR variants is associated with HSP90 and importin α, and the abnormal binding affinities for them play critical roles in this process.