First evidence of genetic association between AKT2 and polycystic ovary syndrome

Molecular crosstalk between insulin-like growth factors and follicle-stimulating hormone in the regulation of granulosa cell function

Background

The last phase of folliculogenesis is driven by follicle-stimulating hormone (FSH) and locally produced insulin-like growth factors (IGFs), both essential for forming preovulatory follicles.

Methods

This review discusses the molecular crosstalk of the FSH and IGF signaling pathways in regulating follicular granulosa cells (GCs) during the antral-to-preovulatory phase.

Main findings

IGFs were considered co-gonadotropins since they amplify FSH actions in GCs. However, this view is not compatible with data showing that FSH requires IGFs to stimulate GCs, that FSH renders GCs sensitive to IGFs, and that FSH signaling interacts with factors downstream of AKT to stimulate GCs. New evidence suggests that FSH and IGF signaling pathways intersect at several levels to regulate gene expression and GC function.

Conclusion

FSH and locally produced IGFs form a positive feedback loop essential for preovulatory follicle formation in all species. Understanding the mechanisms by which FSH and IGFs interact to control GC function will help design new interventions to optimize follicle maturation, perfect treatment of ovulatory defects, improve in vitro fertilization, and develop new contraceptive approaches.

Association between AKT2 gene polymorphism and polycystic ovary syndrome: a case-control study

OBJECTIVE

This study was conducted to understand the association between the AKT2 (AKT serine/threonine kinase 2) gene polymorphism (rs2304186) and PCOS.

METHODS

In total, 1287 participants were included. Six genotype models (Dominant model: TT + TG vs. GG; Recessive model: TT vs. TG + GG; Over-dominant model: TT + GG vs. TG; Co-dominant model: TT vs. TG; Co-dominant TT vs. GG; Allele analysis: T vs. G) were applied in the analysis. According to the races and obesity, subgroup analyses were also performed.

RESULTS

No significant association between rs2304186 and PCOS was identified in the whole sample or the Han groups, even after multi-adjustments. Only in the Zhuang groups was it suggested that rs2304186 might promote the risk of PCOS to some extent (Unadjusted: Over-dominant TT + GG vs. TG, OR = 1.522, 95%CI = 1.076-2.152, p = .018; Age-adjusted: Over-dominant TT + GG vs. TG, OR = 1.543, 95%CI = 1.069-2.228, p = .021; Multi-adjusted: OR = 1.497, 95%CI = 1.024-2.188, p = .037). The risk effect was also detected in the non-obesity group (BMI <24.0 kg/m²) for the Co-dominant model (TT vs. TG: OR = 1.355, 95%CI = 1.001-1.835, p = .050).

CONCLUSIONS

In summary, we first discovered that rs2304186 might significantly elevate the PCOS risk, especially in the Chinese Zhuang population and the non-obesity group. Further studies are needed to confirm these results.

The Effect of Astaxanthin and Metformin on Oxidative Stress in Granulosa Cells of BALB C Mouse Model of Polycystic Ovary Syndrome

Reactive oxygen species (ROS), involved in the pathogenesis of the polycystic ovary syndrome (PCOS), play a key role in the onset of apoptosis in follicles and granulosa cells (GCs). We aimed to investigate the antioxidant effects of AST and metformin separately and in combination on GCs using a PCOS mouse model. Forty-eight prepubertal female BALB C mice aged 25-30 days and weighing 12-14 g were studied. The PCOS model was created by subcutaneous injection of the dehydroepiandrosterone (DHEA) hormone in 8 mice of BALB C for 20 consecutive days. Apoptosis and the amount of ROS were evaluated in GCs of the ovaries via flow cytometry. The activity of AKT protein was measured by western blot, and the viability of GCs was investigated using spectrophotometry. Ovarian tissue sections were prepared, stained with H&E, and the morphology of the sections was examined. Statistical analysis was performed by SPSS v22.0 software using one-way ANOVA. We found that AST administration leads to a significant reduction in oxidative stress (P<0.01) and consequently a significant decrease in the rate of apoptosis (P<0.01). While the expression of AKT in the AST group revealed a significant increase (P<0.05), it decreased in the metformin group. However, it was still significantly higher than the control and PCOS groups. Ovulation was confirmed in both metformin and AST groups. Further studies are warranted to prove the efficacy of AST and to introduce it as a complementary therapeutic agent in PCOS.

In utero exposure to acetaminophen and ibuprofen leads to intergenerational accelerated reproductive aging in female mice

Nonsteroidal anti-inflammatory drugs (NSAIDs) and analgesic drugs, such as acetaminophen (APAP), are frequently taken during pregnancy, even in combination. However, they can favour genital malformations in newborn boys and reproductive disorders in adults. Conversely, the consequences on postnatal ovarian development and female reproductive health after in utero exposure are unknown. Here, we found that in mice, in utero exposure to therapeutic doses of the APAP-ibuprofen combination during sex determination led to delayed meiosis entry and progression in female F1 embryonic germ cells. Consequently, follicular activation was reduced in postnatal ovaries through the AKT/FOXO3 pathway, leading in F2 animals to subfertility, accelerated ovarian aging with abnormal corpus luteum persistence, due to decreased apoptosis and increased AKT-mediated luteal cell survival. Our study suggests that administration of these drugs during the critical period of sex determination could lead in humans to adverse effects that might be passed to the offspring.

Aberrant Akt Activation During Implantation Window in Infertile Women With Intramural Uterine Fibroids

The objective of the study was to examine the expression and cellular distribution of key signaling components of the phosphatidylinositol-3-kinase (PI3K)/Phosphatase and Tensin Homolog Deleted on Chromosome Ten (PTEN)/Protein Kinase B (PKB/Akt) pathway during the window of implantation in infertile women with noncavity-distorting intramural uterine fibroids (n = 21) as compared to fertile controls (n = 15). Relative gene expression analysis of PIK3CA, PTEN, Akt1, and Akt2 genes in midluteal endometrial biopsies was performed by real-time polymerase chain reaction. Immunohistochemistry was used to evaluate the expression of PIK3CA, PTEN, phospho-PTEN, Akt1, Akt2, phospho-Akt1 (serine 473), phospho-Akt1 (threonine 308), and Ki67 proteins. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling assay was performed for apoptosis detection. In comparison to fertile controls, significant upregulation of Akt1 messenger RNA levels (2.16-fold; P < .05); cell-specific upregulation of the proteins phospho-PTEN ( P < .05), Akt1 ( P < .05), Akt2 ( P < .05), and p-Akt (S473; P < .001); and downregulation of PTEN ( P < .01) were observed in endometrium of infertile women with intramural fibroids. The ratio of p-PTEN/PTEN and p-Akt1 (S473)/Akt1 was also significantly higher in infertile women. Increased Ki67 labeling index in the glandular epithelium and significantly lower apoptotic index in glandular epithelium and stroma were seen in infertile women during the window of implantation. Aberrant Akt activation and the associated imbalance in endometrial proliferation and apoptosis observed in infertile women with intramural fibroids during the midsecretory phase might contribute to impaired endometrial receptivity leading to infertility in these patients.

Expression of AKT1 along with AKT2 in granulosa-lutein cells of hyperandrogenic PCOS patients

PURPOSE

AKTs have a pivotal role in the granulosa-lutein cell (GC) proliferation and folliculogenesis, and there is a reciprocal feedback between AKT with androgen. Therefore, we aimed to evaluate the role of AKTs in GCs of hyperandrogenic (+HA) PCOS cases.

METHOD

There were three groups: control, +HA PCOS and -HA (non-hyperandrogenic) PCOS. All groups were subjected to GnRH antagonist protocol for stimulation of ovulation. Follicular fluid was aspirated from large follicles, and GCs were isolated using cell strainer method. AKT1, AKT2, AKT3, and androgen receptor (AR) mRNA expressions were analyzed with quantitative real-time PCR (qRT-PCR), and total-AKT and p-AKT (Ser⁴⁷³ & Thr³⁰⁸) were investigated using western blotting.

RESULTS

There were high levels of AKT1, AKT2, and AR mRNA expressions and high levels of p-AKT protein expression in the +HA PCOS group (p ≤ 0.05). There was a direct positive correlation between free testosterone (FT) and total testosterone (TT) with the levels of AKT1, AKT2, and p-AKT (Ser⁴⁷³), and also between FT with the levels of AR.

CONCLUSION

High expressions of AKT1 and AKT2 through possible relation with androgen may cause GCs dysfunction in the +HA PCOS patients.

Effect of maternal PCOS and PCOS-like phenotype on the offspring's health

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder with both reproductive and metabolic abnormalities affecting women of reproductive age. While the exact origin of PCOS is unknown, observations from clinical and animal studies suggest that maternal hyperandrogenism may be a contributing factor. Because women with PCOS manifest hyperandrogenism during pregnancy, changes in the gestational endocrine milieu may play a role in the vertical transmission of this syndrome. This review discusses the potential developmental origins of PCOS, the impact of maternal PCOS on the offspring's health and contributions of the postnatal environment, capitalizing on findings from animal models that exhibit a PCOS-like phenotype. In addition, this review highlights the scarcity of data at early gestational stages in humans and the importance of animal experimentation to better understand the cellular and molecular mechanisms involved in the programming of adult diseases, therefore, helping identify therapeutic targets for preventive and treatment strategies.

Sirolimus and Everolimus Pathway: Reviewing Candidate Genes Influencing Their Intracellular Effects

Sirolimus (SRL) and everolimus (EVR) are mammalian targets of rapamycin inhibitors (mTOR-I) largely employed in renal transplantation and oncology as immunosuppressive/antiproliferative agents. SRL was the first mTOR-I produced by the bacterium Streptomyces hygroscopicus and approved for several medical purposes. EVR, derived from SRL, contains a 2-hydroxy-ethyl chain in the 40th position that makes the drug more hydrophilic than SRL and increases oral bioavailability. Their main mechanism of action is the inhibition of the mTOR complex 1 and the regulation of factors involved in a several crucial cellular functions including: protein synthesis, regulation of angiogenesis, lipid biosynthesis, mitochondrial biogenesis and function, cell cycle, and autophagy. Most of the proteins/enzymes belonging to the aforementioned biological processes are encoded by numerous and tightly regulated genes. However, at the moment, the polygenic influence on SRL/EVR cellular effects is still not completely defined, and its comprehension represents a key challenge for researchers. Therefore, to obtain a complete picture of the cellular network connected to SRL/EVR, we decided to review major evidences available in the literature regarding the genetic influence on mTOR-I biology/pharmacology and to build, for the first time, a useful and specific “SRL/EVR genes-focused pathway”, possibly employable as a starting point for future in-depth research projects.

Evaluating reported candidate gene associations with polycystic ovary syndrome

OBJECTIVE

To replicate variants in candidate genes associated with polycystic ovary syndrome (PCOS) in a population of European women with PCOS and control subjects.

DESIGN

Case-control association analysis and meta-analysis.

SETTING

Major academic hospital.

PATIENT(S)

Women of European ancestry with PCOS (n = 525) and controls (n = 472), aged 18-45 years.

INTERVENTION(S)

Variants previously associated with PCOS in candidate gene studies were genotyped (n = 39). Metabolic, reproductive, and anthropomorphic parameters were examined as a function of the candidate variants. All genetic association analyses were adjusted for age, body mass index, and ancestry and were reported after correction for multiple testing.

MAIN OUTCOME MEASURE(S)

Association of candidate gene variants with PCOS.

RESULT(S)

Three variants, rs3797179 (SRD5A1), rs12473543 (POMC), and rs1501299 (ADIPOQ), were nominally associated with PCOS. However, they did not remain significant after correction for multiple testing, and none of the variants replicated in a sufficiently powered meta-analysis. Variants in the FBN3 gene (rs17202517 and rs73503752) were associated with smaller waist circumferences, and variant rs727428 in the SHBG gene was associated with lower sex hormone-binding globulin levels.

CONCLUSION(S)

Previously identified variants in candidate genes do not seem to be associated with PCOS risk.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00166569.

Apolipoprotein A-IV as a novel gene associated with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine-metabolic disorder, affecting 6-10% of women of reproductive age. The etiology remains poorly understood. To investigate the differentially expressed proteins from PCOS patients versus healthy women, the protein expression in follicular fluid was analyzed using two-dimensional electrophoresis (2-DE). Since follicular fluid contains a number of secretory proteins required for oocyte fertilization and follicle maturation, it is possible that follicular fluid can be used as a provisional source for identifying pivotal proteins associated with PCOS. In this study, six overexpressed proteins [kininogen 1, cytokeratin 9, antithrombin, fibrinogen γ-chain, apolipoprotein A-IV (apoA-IV) precursor and α-1-B-glycoprotein (A1BG)] in follicular fluids from PCOS patients were identified with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) and nano LC-MS/MS. Western blot analysis confirmed that the protein expression levels of apoA-IV precursor and A1BG were increased in follicular fluid from PCOS patients compared with those from normal controls. The analysis of protein expression for other proteins revealed individual variation. These results facilitate the understanding of the molecular mechanisms of PCOS and provide candidate biomarkers for the development of diagnostic and therapeutic tools.

Low-dose oral sirolimus and the risk of menstrual-cycle disturbances and ovarian cysts: analysis of the randomized controlled SUISSE ADPKD trial

Sirolimus has been approved for clinical use in non proliferative and proliferative disorders. It inhibits the mammalian target of rapamycin (mTOR) signaling pathway which is also known to regulate ovarian morphology and function. Preliminary observational data suggest the potential for ovarian toxicity but this issue has not been studied in randomized controlled trials. We reviewed the self-reported occurrence of menstrual cycle disturbances and the appearance of ovarian cysts post hoc in an open label randomized controlled phase II trial conducted at the University Hospital Zürich between March 2006 and March 2010. Adult females with autosomal dominant polycystic kidney disease, an inherited kidney disease not known to affect ovarian morphology and function, were treated with 1.3 to 1.5 mg sirolimus per day for a median of 19 months (N = 21) or standard care (N = 18). Sirolimus increased the risk of both oligoamenorrhea (hazard ratio [HR] 4.3, 95% confidence interval [CI] 1.1 to 29) and ovarian cysts (HR 4.4, CI 1.1 to 26); one patient was cystectomized five months after starting treatment with sirolimus. We also studied mechanisms of sirolimus-associated ovarian toxicity in rats. Sirolimus amplified signaling in rat ovarian follicles through the pro-proliferative phosphatidylinositol 3-kinase pathway. Low dose oral sirolimus increases the risk of menstrual cycle disturbances and ovarian cysts and monitoring of sirolimus-associated ovarian toxicity is warranted and might guide clinical practice with mammalian target of rapamycin inhibitors.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00346918.

Genome-wide association study identifies GYS2 as a novel genetic factor for polycystic ovary syndrome through obesity-related condition

To investigate the role of genetic predisposition in the pathogenesis of polycystic ovary syndrome (PCOS) in relation to obesity, we performed a genome-wide association study of PCOS in Koreans (n=1741). PCOS is a heterogeneous endocrinal disorder of uncertain etiology. Obesity is one of the well-known risk factors for PCOS. Genome-wide association study. Women with or without PCOS. A total of 1881 samples were genotyped using Illumina HumanOmni1 Quad v1 and processed by R packages. The PCOS patients were divided into two subgroups according to PCOS diagnostic criteria (Rotterdam and National Institutes of Health (NIH)). For PCOS-associated loci in the two definitions, we successfully confirmed significant associations of GYS2 for body mass index in the discovery stage. We further replicated pleiotropic associations of GYS2 in a childhood obesity study (n=482) and in a gestational diabetes study (n=1710), respectively. Our study provides a preliminary framework upon diverse genetic effects underlying PCOS in Korean women. A newly identified GYS2 gene as a predisposing factor of PCOS might expand understanding of the biological pathways in metabolic and endocrine regulation.

PI3K-Akt-mTOR and MAPK signaling pathways in polycystic ovarian syndrome, uterine leiomyomas and endometriosis: an update

PI3K-Akt-mTOR and MAP kinase are two important cell signaling pathways that are activated by steroid hormones and growth factors leading to cellular events including gene expression, cell proliferation and survival. These pathways are considered as an attractive target for the development of novel anticancer molecules, and selective inhibitors specifically targeting different components of these cascades have been developed. This review summarizes the current available knowledge on the PI3K-Akt-mTOR and MAPK pathways and their targeting in estrogen-dependent benign gynecological disorders viz. polycystic ovarian syndrome, uterine leiomyomas and endometriosis, which are a significant cause of high morbidity in women of reproductive age group. Increasing knowledge about the role of the two growth regulatory pathways in the pathogenesis of these disorders may give the opportunity to use specific signal transduction inhibitors for management of these patients in future.

Loss of PKBβ/Akt2 predisposes mice to ovarian cyst formation and increases the severity of polycystic ovary formation in vivo

Ovarian cysts affect women of all ages and decrease fertility. In particular, polycystic ovarian syndrome (PCOS), in which multiple follicular cysts develop, affects 5–10% of women of reproductive age and can result in infertility. Current non-invasive treatments for PCOS can resolve cysts and restore fertility, but unresponsive patients must undergo severe ovarian wedge resection and resort to in vitro fertilization. PCOS is related to the deregulation of leutinizing hormone (LH) signaling at various levels of the hypothalamic-pituitary-ovarian axis and resultant hyperproduction of androgens. Because insulin resistance and compensatory hyperinsulinemia are observed in 50–70% of individuals with PCOS, deregulated insulin signaling in the ovary is considered an important factor in the disease. Here we report that aged mice specifically lacking the PKBβ (also known as Akt2) isoform that is crucial for insulin signaling develop increased testosterone levels and ovarian cysts, both of which are also observed in insulin-resistant PCOS patients. Young PKBβ knockout mice were used to model PCOS by treatment with LH and exhibited a cyst area that was threefold greater than in controls, but without hyperinsulinemia. Thus, loss of PKBβ might predispose mice to ovarian cysts independently of hyperactive insulin signaling. Targeted therapeutic augmentation of specific PKBβ signaling could therefore provide a new avenue for the treatment and management of ovarian cysts.

Reproductive tissues maintain insulin sensitivity in diet-induced obesity

Reproductive dysfunction is associated with obesity. We previously showed that female mice with diet-induced obesity (DIO) exhibit infertility and thus serve as a model of human polycystic ovary syndrome (PCOS). We postulated that differential insulin signaling of tissues leads to reproductive dysfunction; therefore, a comparison of insulin signaling in reproductive tissues and energy storage tissues was performed. Pituitary-specific insulin receptor knockout mice were used as controls. High-fat diet-induced stress, which leads to insulin resistance, was also investigated by assaying macrophage infiltration and phosphorylated Jun NH(2)-terminal kinase (pJNK) signaling. In lean mice, reproductive tissues exhibited reduced sensitivity to insulin compared with peripheral metabolic tissues. However, in obese mice, where metabolic tissues exhibited insulin resistance, the pituitary and ovary maintained insulin sensitivity. Pituitaries responded to insulin through insulin receptor substrate (IRS)2 but not IRS1, whereas in the ovary, both IRS1 and IRS2 were activated by insulin. Macrophage infiltration and pJNK signaling were not increased in the pituitary or ovary of lean mice relative to DIO mice. The lack of inflammation and cytokine signaling in the pituitary and ovary in DIO mice compared with lean mice may be one of the reasons that these tissues remained insulin sensitive. Retained sensitivity of the pituitary and ovary to insulin may contribute to the pathophysiology of PCOS.

Epigenetic mechanism underlying the development of polycystic ovary syndrome (PCOS)-like phenotypes in prenatally androgenized rhesus monkeys

The pathogenesis of polycystic ovary syndrome (PCOS) is poorly understood. PCOS-like phenotypes are produced by prenatal androgenization (PA) of female rhesus monkeys. We hypothesize that perturbation of the epigenome, through altered DNA methylation, is one of the mechanisms whereby PA reprograms monkeys to develop PCOS. Infant and adult visceral adipose tissues (VAT) harvested from 15 PA and 10 control monkeys were studied. Bisulfite treated samples were subjected to genome-wide CpG methylation analysis, designed to simultaneously measure methylation levels at 27,578 CpG sites. Analysis was carried out using Bayesian Classification with Singular Value Decomposition (BCSVD), testing all probes simultaneously in a single test. Stringent criteria were then applied to filter out invalid probes due to sequence dissimilarities between human probes and monkey DNA, and then mapped to the rhesus genome. This yielded differentially methylated loci between PA and control monkeys, 163 in infant VAT, and 325 in adult VAT (BCSVD P<0.05). Among these two sets of genes, we identified several significant pathways, including the antiproliferative role of TOB in T cell signaling and transforming growth factor-β (TGF-β) signaling. Our results suggest PA may modify DNA methylation patterns in both infant and adult VAT. This pilot study suggests that excess fetal androgen exposure in female nonhuman primates may predispose to PCOS via alteration of the epigenome, providing a novel avenue to understand PCOS in humans.

Replication of association of a novel insulin receptor gene polymorphism with polycystic ovary syndrome

OBJECTIVE

To evaluate association with polycystic ovary syndrome (PCOS) of 295 variants in 39 genes central to metabolic insulin signaling and glycogen synthase kinase 3β (GSK-3β) regulation, followed by replication efforts.

DESIGN

Case-control association study, with discovery and replication cohorts.

SETTING

Subjects were recruited from reproductive endocrinology clinics, and controls were recruited from communities surrounding the University of Alabama at Birmingham and Erasmus Medical Center, Rotterdam.

PATIENT(S)

A total of 273 cases with PCOS and 173 control subjects in the discovery cohort; and 526 cases and 3,585 control subjects in the replication cohort. All subjects were caucasian.

INTERVENTION(S)

Phenotypic and genotypic assessment.

MAIN OUTCOME MEASURE(S)

Detection of 295 single-nucleotide polymorphisms (SNPs), PCOS status.

RESULT(S)

Several SNPs were associated with PCOS in the discovery cohort. Four insulin receptor (INSR) SNPs and three insulin receptor substrate 2 (IRS2) SNPs associated with PCOS were genotyped in the replication cohort. One INSR SNP (rs2252673) replicated association with PCOS. The minor allele conferred increased odds of PCOS in both cohorts, independent of body mass index.

CONCLUSION(S)

A pathway-based tagging SNP approach allowed us to identify novel INSR SNPs associated with PCOS, one of which confirmed association in a large replication cohort.

Systematic review: association of polycystic ovary syndrome with metabolic syndrome and non-alcoholic fatty liver disease

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common disorder for women of child-bearing age and is associated with metabolic syndrome (MS).

AIM

To assess the literature for associations between polycystic ovary syndrome and non-alcoholic fatty liver disease (NAFLD).

METHODS

We performed a systematic review using PubMed-search for peer-reviewed articles related to polycystic ovary syndrome and NAFLD. Articles were summarised and grouped according to different sections defining interactions of polycystic ovary syndrome with metabolic syndrome and non-alcoholic fatty liver disease as well as risk factors, pathogenic pathways and treatment options.

RESULTS

Obesity is a common factor involved in both polycystic ovary syndrome and non-alcoholic fatty liver disease. Obesity causes non-alcoholic fatty liver disease and aggravates hirsutism and menstrual disorders in polycystic ovary syndrome. Insulin resistance, a hallmark of metabolic syndrome is observed in 50-80% of women with polycystic ovary syndrome and patients with non-alcoholic fatty liver disease. Recent findings suggest that women with polycystic ovary syndrome may be at risk for developing non-alcoholic fatty liver disease and conversely, non-alcoholic fatty liver disease may be a risk for polycystic ovary syndrome. Based on the association of polycystic ovary syndrome and other metabolic abnormalities, such as insulin resistance, hyperandrogenism, obesity and non-alcoholic fatty liver disease, the candidate genes have been speculated for polycystic ovary syndrome. Closer scrutiny of these genes placed most of their proteins at the crossroads of three highly inter-related conditions: metabolic syndrome, obesity and non-alcoholic fatty liver disease. In most studies, the prevalence of both polycystic ovary syndrome and non-alcoholic fatty liver disease rises proportionally to the degree of insulin resistance and increases in the mass of adipose tissue.

CONCLUSIONS

Non-alcoholic fatty liver disease is considered as the hepatic manifestation of metabolic syndrome. Similarly, it seems appropriate to consider polycystic ovary syndrome as the ovarian manifestation of metabolic syndrome. Both these conditions can co-exist and may respond to similar therapeutic strategies.

Epigenetics in polycystic ovary syndrome: a pilot study of global DNA methylation

The percent global methylation of peripheral blood DNA was not significantly altered in 20 women with polycystic ovary syndrome (PCOS) compared with 20 controls. The study of specific tissues and target genomic regions will be required to further determine whether epigenetic alteration influences the development of PCOS.

Glycogen synthase kinase 3B in bovine oocytes and granulosa cells: possible involvement in meiosis during in vitro maturation

Glycogen synthase kinase 3 (GSK3) regulates cellular metabolism and cell cycle via different signalling pathways. In response to insulin and growth factors GSK3 is serine-phosphorylated and inactivated. We analysed GSK3B expression and activation in bovine cumulus cells (CC) and oocytes at different meiotic stagesin vitroin parallel with MAP kinases ERK (MAPK3/MAPK1) and p38 (MAPK14). GSK3B localised to cytoplasm in granulosa cells and in oocytes throughout folliculogenesis. In mature metaphase-II (MII) oocytes, GSK3B was concentrated to the region of midzone between the oocyte and the first polar body, as well as active phospho-Thr Aurora A kinase (AURKA). Duringin vitromaturation (IVM), in oocytes, phospho-Ser9-GSK3B level increased as well as phospho-MAPK3/MAPK1, while phospho-MAPK14 decreased. In CC, phospho-MAPK14 increased upon germinal vesicle breakdown (GVBD)/metaphase-I (MI) and then decreased during transition to MII. Administration of inhibitors of GSK3 activity (lithium chloride or 2′Z,3′E -6-bromoindirubin-3′-oxime) rapidly increased phospho-Ser9-GSK3B, and led to transient decrease of phospho-MAPK3/MAPK1 and to durable enhancing of phospho-MAPK14 in granulosa primary cell culture. GSK3 inhibitors during IVM diminished cumulus expansion and delayed meiotic progression. In cumulus, phospho-MAPK14 level was significantly higher in the presence of inhibitors, comparing with control, through the time of MI/MII transition. In oocytes, phospho-GSK3B was increased and phospho-MAPK3/MAPK1 was decreased before GVBD and oocytes were mainly arrested at MI. Therefore, GSK3B might regulate oocyte meiosis, notably MI/MII transition being the part of MAPK3/1 and MAPK14 pathways in oocytes and CC. GSK3B might be also involved in the local activation of AURKA that controls this transition.