A role for neurotransmitters in early follicular development: induction of functional follicle-stimulating hormone receptors in newly formed follicles of the rat ovary

Increased Vasoactive Intestinal Peptide (VIP) in polycystic ovary syndrome patients undergoing IVF

Introduction

Polycystic ovary syndrome (PCOS) is a common multifactorial and polygenic disorder of the endocrine system, affecting up to 20% of women in reproductive age with a still unknown etiology. Follicular fluid (FF) represents an environment for the normal development of follicles rich in metabolites, hormones and neurotransmitters, but in some instances of PCOS the composition can be different. Vasoactive intestinal peptide (VIP) is an endogenous autonomic neuropeptide involved in follicular atresia, granulosa cell physiology and steroidogenesis.

Methods

ELISA assays were performed to measure VIP and estradiol levels in human follicular fluids, while AMH, FSH, LH, estradiol and progesterone in the plasma were quantified by chemiluminescence. UHPLC/QTOF was used to perform the untargeted metabolomic analysis.

Results

Our ELISA and metabolomic results show: i) an increased concentration of VIP in follicular fluid of PCOS patients (n=9) of about 30% with respect to control group (n=10) (132 ± 28 pg/ml versus 103 ± 26 pg/ml, p=0,03) in women undergoing in vitro fertilization (IVF), ii) a linear positive correlation (p=0.05, r=0.45) between VIP concentration and serum Anti-Müllerian Hormone (AMH) concentration and iii) a linear negative correlation between VIP and noradrenaline metabolism. No correlation between VIP and estradiol (E2) concentration in follicular fluid was found. A negative correlation was found between VIP and noradrenaline metabolite 3,4-dihydroxyphenylglycolaldehyde (DOPGAL) in follicular fluids.

Conclusion

VIP concentration in follicular fluids was increased in PCOS patients and a correlation was found with noradrenaline metabolism indicating a possible dysregulation of the sympathetic reflex in the ovarian follicles. The functional role of VIP as noradrenergic modulator in ovarian physiology and PCOS pathophysiology was discussed.

GWAS of Dizygotic Twinning in an Enlarged Australian Sample of Mothers of DZ Twins

Female fertility is a complex trait with age-specific changes in spontaneous dizygotic (DZ) twinning and fertility. To elucidate factors regulating female fertility and infertility, we conducted a genome-wide association study (GWAS) on mothers of spontaneous DZ twins (MoDZT) versus controls (3273 cases, 24,009 controls). This is a follow-up study to the Australia/New Zealand (ANZ) component of that previously reported (Mbarek et al., 2016), with a sample size almost twice that of the entire discovery sample meta-analysed in the previous article (and five times the ANZ contribution to that), resulting from newly available additional genotyping and representing a significant increase in power. We compare analyses with and without male controls and show unequivocally that it is better to include male controls who have been screened for recent family history, than to use only female controls. Results from the SNP based GWAS identified four genomewide significant signals, including one novel region, ZFPM1 (Zinc Finger Protein, FOG Family Member 1), on chromosome 16. Previous signals near FSHB (Follicle Stimulating Hormone beta subunit) and SMAD3 (SMAD Family Member 3) were also replicated (Mbarek et al., 2016). We also ran the GWAS with a dominance model that identified a further locus ADRB2 on chr 5. These results have been contributed to the International Twinning Genetics Consortium for inclusion in the next GWAS meta-analysis (Mbarek et al., in press).

SARS-CoV-2 infection and female reproductive health: A narrative review

The COVID-19 pandemic has had a profound global impact, affecting people's physical and mental health, and their social and economic circumstances. Mitigation measures have disproportionately affected women. Studies have reported menstrual cycle and psychological disturbance associated with the pandemic. Pregnancy is a risk factor for severe COVID-19 disease. Reports have also demonstrated associations between COVID-19 infection, vaccination and Long COVID syndrome and reproductive health disturbance. However, studies are limited and there may be significant geographical variation. Also there is bias amongst published studies, and menstrual cycle data was not included in COVID-19 and vaccine trials. Longitudinal population based studies are required. In this review we discuss existing data, along with recommendations for further research required in this area. We also discuss a pragmatic approach to women presenting with reproductive health disturbance in the era of the pandemic, encompassing a multi-system assessment of psychological, reproductive health and lifestyle.

The investigation of cholinergic receptor muscarinic 1 activity in the rat ovary with induced ovarian hyperstimulation

Objective

We look at the immunoreactivity of cholinergic receptor muscarinic 1 (CHRM1) in the ovarian tissues of rats with ovarian hyperstimulation syndrome (OHSS) considering the possibility that the muscarinic activity may contribute to the pathophysiology of OHSS.

Materials and Methods

In this study, 14 immature female Wistar Albino rats were divided into two groups at random. The rats were 22 days old. Rats in the control group (n=7) were 22 days old, while those in the OHSS group (n=7) received 10 IU follicle-stimulating hormone subcutaneously over the course of four days and 30 IU human chorionic gonadotropin (hCG) on the fifth day to induce ovarian hyperstimulation. All the rats were sacrificed after all the groups' ovaries and blood samples were collected at the conclusion of the experiment. The left ovarian tissues were kept in aluminum foil at -80 °C, while the right ovarian tissues were kept in 10% formalin. Tissue vascular endothelial growth factor (VEGF), interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor (TNF)-α and malondialdehyde (MDA) levels were measured by The Enzyme Linked Immunosorbent Assay technique in the ovarian tissues. CHRM1 immunoreactivity was scored immunohistochemically.

Results

Ovarian weight, tissue IL-10, TNF-α, VEGF and MDA levels, and CHRM1 immunoreactivity were significantly increased in the OHSS group.

Conclusion

Increased levels of CHRM1 activity may play a role in the pathophysiology of OHSS. With further studies, the effect of luteinizing hormone and hCG on the ovarian and hypothalamic cholinergic system can be further investigated, and useful information can be obtained in determining OHSS prevention strategies.

Altered GnRH neuron and ovarian innervation characterize reproductive dysfunction linked to the Fragile X messenger ribonucleoprotein (Fmr1) gene mutation

Introduction

Mutations in the Fragile X Messenger Ribonucleoprotein 1 (FMR1) gene cause Fragile X Syndrome, the most common monogenic cause of intellectual disability. Mutations of FMR1 are also associated with reproductive disorders, such as early cessation of reproductive function in females. While progress has been made in understanding the mechanisms of mental impairment, the causes of reproductive disorders are not clear. FMR1-associated reproductive disorders were studied exclusively from the endocrine perspective, while the FMR1 role in neurons that control reproduction was not addressed.

Results

Here, we demonstrate that similar to women with FMR1 mutations, female Fmr1 null mice stop reproducing early. However, young null females display larger litters, more corpora lutea in the ovaries, increased inhibin, progesterone, testosterone, and gonadotropin hormones in the circulation. Ovariectomy reveals both hypothalamic and ovarian contribution to elevated gonadotropins. Altered mRNA and protein levels of several synaptic molecules in the hypothalamus are identified, indicating reasons for hypothalamic dysregulation. Increased vascularization of corpora lutea, higher sympathetic innervation of growing follicles in the ovaries of Fmr1 nulls, and higher numbers of synaptic GABAA receptors in GnRH neurons, which are excitatory for GnRH neurons, contribute to increased FSH and LH, respectively. Unmodified and ovariectomized Fmr1 nulls have increased LH pulse frequency, suggesting that Fmr1 nulls exhibit hyperactive GnRH neurons, regardless of the ovarian feedback.

Conclusion

These results reveal Fmr1 function in the regulation of GnRH neuron secretion, and point to the role of GnRH neurons, in addition to the ovarian innervation, in the etiology of Fmr1-mediated reproductive disorders.

iPSCs-derived mesenchymal stromal cells mitigate anxiety and neuroinflammation in aging female mice

Perimenopause is a natural transition to menopause, when hormone disturbance can result in both short-term mental disorders, such as anxiety, and long-term neuroinflammation due to blood-brain barrier (BBB) impairment, which may lead to more serious neurological disorders later on, such as dementia. Effective treatments may prevent both short-term and long-term neurological sequela, which formed the aim of this study. In aged female C57BL/6 mice (16-18 months of age), mesenchymal stromal cells (MSCs) differentiated from human-induced pluripotent stem cells (iPSCs), were administered via tail vein injection. Mice showed increased blood estrogen levels, alleviated anxiety and neuroinflammation, and improved BBB integrity. Interestingly, transplanted MSCs were located close to ovarian sympathetic nerves and decreased ovarian norepinephrine levels, which in turn increased ovarian estrogen secretion. Moreover, the administration of anastrozole, an inhibitor of estrogen synthesis, diminished the therapeutic effects of MSCs in vivo, suggesting the effect to be estrogen-dependent. In vitro study confirmed the impact of MSCs on sympathetic nerves via mitochondria exchange. In conclusion, iPSC-derived MSCs may provide a novel option to manage perimenopause-related hormonal dysregulation and neurological disorders during the female aging process.

Menstrual cycle changes: A cross-sectional study of Saudi females following SARS-CoV-2 infection

Temporary changes in the menstrual cycle have recently been reported following SARS-CoV-2 vaccination. In the current study, we aimed to screen menstrual cycle changes following SARS-CoV-2 infection in Saudi Arabia. The type and duration of these changes have been screened in relation to the severity of coronavirus disease symptoms and vaccination status. In total, 956 individuals responded: sixty-nine did not get the COVID-19 vaccine, while the remaining were vaccinated with either a single dose of ChAdOx1 vaccine (n:45) or BNT162b2 vaccine (n: 142) or two doses of the vaccine (n:700) using BNT162b2 (n:477), ChAdOx1 (n:89) or ChAdOx1/ BNT162b2 (n:134). Approximately 26.1% (18/69) of the subjects who did not receive the SARS-CoV-2 vaccine and 15.3% (29/188) and 26.4% (185/700) of the subjects who received single and double doses of the vaccines, respectively, reported menstrual cycle changes. The persistence of menstrual cycle changes for more than six months was reported by 6.4% (61/956) of the participants. These changes were significantly correlated with the severity of COVID-19 infection. We concluded that menstrual cycle changes, associated with COVID-19 infection, increase due to the severity of COVID-19 infection. Thus, menstrual cycle changes are among the long-term effects associated with COVID-19 infection.

Stimulatory Effects of Androgens on Eel Primary Ovarian Development - from Phenotypes to Genotypes

Androgens stimulate primary ovarian development in Vertebrate. Japanese eels underwent operation to sample the pre- and post-treated ovarian tissues from the same individual. Ovarian phenotypic or genotypic data were mined in a pair. A correlation between the initial ovarian status (determined by kernel density estimation (KDE), presented as a probability density of oocyte size) and the consequence of androgen (17MT) treatment (change in ovary) has been showed. The initial ovarian status appeared to be important to influence ovarian androgenic sensitivity. The initial ovary was important to the outcomes of androgen treatments, and ePAV (expression presence-absence variation) is existing in Japanese eel by analyze DEGs; core, unique, or accessory genes were identified, the sensitivities of initial ovaries were correlated with their gene expression profiles. We speculated the importance of genetic differential expression on the variations of phenotypes by 17MT, and transcriptomic approach seems to allow extracting multiple layers of genomic data.

Female Reproductive Health Disturbance Experienced During the COVID-19 Pandemic Correlates With Mental Health Disturbance and Sleep Quality

The COVID-19 pandemic has adversely affected population mental health. Periods of psychological distress can induce menstrual dysfunction. We previously demonstrated a significant disruption in women's reproductive health during the first 6 months of the pandemic. The present study investigates longer-term reproductive and mental health disturbances. A cross-sectional online survey was completed by 1335 women of reproductive age in April 2021. It included validated standardized measures of depression (PHQ-9), anxiety (GAD-7) and sleep quality (PSQI). 581 (56%) of women reported an overall change in their menstrual cycle since the beginning of the pandemic. There was no change in median cycle length [28 days (28-30)] or days of menses [5 (4-5)], but there was a wider variability in minimum (p<0.0001) and maximum (p<0.0001) cycle length. There was a significant increase in heavy menstrual bleeding, painful periods and missed periods compared to pre-pandemic (all p<0.0001). 64% of women reported worsening pre-menstrual symptoms. Rates of severe depression, anxiety and poor sleep were more than double those from large scale representative community samples. Poor sleep quality was an independent predictor of overall change in menstrual cycle (OR=1.11, 95%CI 1.05-1.18), and missed periods (OR=1.11, 95%CI 1.03-1.19) during the pandemic. Increased anxiety was independently associated with a change from non-painful to painful periods (OR=1.06, 95%CI 1.01-1.11) and worsening of pre-menstrual symptoms (OR=1.06, 95%CI 1.01-1.07) during the pandemic. The COVID-19 pandemic continues to bear a significant impact on female reproductive health. Increased levels of psychological distress and poor sleep are associated with menstrual cycle disruption.

Intrinsic innervation of the ovary and its variations in the rat senescence process

Ovarian functions decrease with perimenopause. The ovary has extrinsic innervation, but the neural influence on ovarian functions and dysfunction is not well-studied. The present study aimed to biochemically and morphometrically characterize the intrinsic neurons in ovaries from young adult, middle-aged, and senescent Long Evans CII-ZV rats (3, 12, and 15 months old, respectively). Ovaries were extracted from four rats of each age group (n = 12 total), cryopreserved, and processed for immunofluorescence studies with the primary NeuN/β-tubulin and NeuN/tyrosine hydroxylase (TH) antibodies. The soma area and number of intrinsic neurons in the ovarian stroma, surrounding follicles, corpus luteum, or cyst were evaluated. The intrinsic neurons were grouped in cluster-like shapes in ovarian structures. In senescent rats, the intrinsic neurons were mainly localized in the ovarian stroma and around the cysts. The number of neurons was lower in senescent rats than in young adult rats (p < 0.05), but the soma size was larger than in young adult rats. Immunoreactivity to TH indicated the presence of noradrenergic neurons in the ovary with the same characteristics as NeuN/β-tubulin, which indicates that they are part of the same neuronal group. Taken together, the findings indicate that the intrinsic neurons may be related to the loss of ovarian functions associated with aging.

Transcriptome comparative analysis of ovarian follicles reveals the key genes and signaling pathways implicated in hen egg production

Background

Ovarian follicle development plays an important role in determination of poultry egg production. The follicles at the various developmental stages possess their own distinct molecular genetic characteristics and have different biological roles in chicken ovary development and function. In the each stage, several genes of follicle-specific expression and biological pathways are involved in the vary-sized follicular development and physiological events. Identification of the pivotal genes and signaling pathways that control the follicular development is helpful for understanding their exact regulatory functions and molecular mechanisms underlying egg-laying traits of laying hens.

Results

The comparative mRNA transcriptomic analysis of ovarian follicles at three key developmental stages including slow growing white follicles (GWF), small yellow follicles (SYF) of recruitment into the hierarchy, and differentiated large yellow follicles (LYF), was accomplished in the layers with lower and higher egg production. Totally, 137, 447, and 229 of up-regulated differentially expressed genes (DEGs), and 99, 97, and 157 of down-regulated DEGs in the GWF, SYF and LYF follicles, including VIPR1, VIPR2, ADRB2, and HSD17B1 were identified, respectively. Moreover, NDUFAB1 and GABRA1 genes, two most promising candidates potentially associated with egg-laying performance were screened out from the 13 co-expressed DEGs in the GWF, SYF and LYF samples. We further investigated the biological effects of NDUFAB1 and GABRA1 on ovarian follicular development and found that NDUFAB1 promotes follicle development by stimulating granulosa cell (GC) proliferation and decreasing cell apoptosis, increases the expression of CCND1 and BCL-2 but attenuates the expression of caspase-3, and facilitates steroidogenesis by enhancing the expression of STAR and CYP11A1. In contrast, GABRA1 inhibits GC proliferation and stimulates cell apoptosis, decreases the expression of CCND1, BCL-2, STAR, and CYP11A1 but elevates the expression of caspase-3. Furthermore, the three crucial signaling pathways such as PPAR signaling pathway, cAMP signaling pathway and neuroactive ligand-receptor interaction were significantly enriched, which may play essential roles in ovarian follicle growth, differentiation, follicle selection, and maturation.

Conclusions

The current study provided new molecular data for insight into the regulatory mechanism underlying ovarian follicle development associated with egg production in chicken.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-08213-w.

rno-miR-128-3p promotes apoptosis in rat granulosa cells (GCs) induced by norepinephrine through Wilms tumor 1 (WT1)

The mechanism related to ovarian follicular is complex, which has not been fully elucidated. Abundant reports have confirmed that the ovarian function development is closely related to sympathetic innervation. As one of the major neurotransmitters, norepinephrine (NE) is considered an effective regulator of ovarian functions like granulosa cell (GC) apoptosis. However, the mechanism between NE and GC apoptosis in rat is still unclear. In our study, GCs were isolated and cultured in vitro with NE treatment. The apoptosis of GCs was facilitated by NE. Wilms tumor 1 (WT1) was found to be significantly downregulated in GCs after NE treatment, and overexpression of WT1 repressed apoptosis in rat GCs induced by NE. rno-miR-128-3p was found to be significantly enhanced by NE in GCs, and inhibition of rno-miR-128-3p repressed apoptosis in rat GCs induced by NE. Mechanistically, rno-miR-128-3p interacted with WT1 and repressed its expression. In summary, inhibition of rno-miR-128-3p may enhance WT1 expression, and then repress NE-induced apoptosis in rat GCs. Our research may provide a new insight for the improvement of ovarian follicular development.

Androgenic Sensitivities and Ovarian Gene Expression Profiles Prior to Treatment in Japanese Eel (Anguilla japonica)

Androgens stimulate ovarian development in eels. Our previous report indicated a correlation between the initial (debut) ovarian status (determined by kernel density estimation (KDE), presented as a probability density of oocyte size) and the consequence of 17MT treatment (change in ovary). The initial ovarian status appeared to be an important factor influencing ovarian androgenic sensitivity. We postulated that the sensitivities of initial ovaries are correlated with their gene expression profiles. Japanese eels underwent operation to sample the initial ovarian tissues, and the samples were stored in liquid nitrogen. Using high-throughput next-generation sequencing (NGS) technology, ovarian transcriptomic data were mined and analyzed based on functional gene classification with cutoff-based differentially expressed genes (DEGs); the ovarian status was transformed into gene expression profiles globally or was represented by a set of gene list. Our results also implied that the initial ovary might be an important factor influencing the outcomes of 17MT treatments, and the genes related with neuronal activities or neurogenesis seemed to play an essential role in the positive effect.

The Impact of the COVID-19 Pandemic on Women's Reproductive Health

BACKGROUND

The COVID-19 pandemic has profoundly affected the lives of the global population. It is known that periods of stress and psychological distress can affect women's menstrual cycles. We therefore performed an observational study of women's reproductive health over the course of the pandemic thus far.

MATERIALS AND METHODS

An anonymous digital survey was shared by the authors via social media in September 2020. All women of reproductive age were invited to complete the survey.

RESULTS

1031 women completed the survey. Mean age was 36.7 ± 6.6 years (range, 15-54). 693/70% reported recording their cycles using an app or diary. 233/23% were using hormonal contraception. 441/46% reported a change in their menstrual cycle since the beginning of the pandemic. 483/53% reported worsening premenstrual symptoms, 100/18% reported new menorrhagia (p = 0.003) and 173/30% new dysmenorrhea (p < 0.0001) compared to before the pandemic. 72/9% reported missed periods who not previously missed periods (p = 0.003) and the median number of missed periods was 2 (1-3). 17/21% of those who "occasionally" missed periods pre-pandemic missed periods "often" during pandemic. 467/45% reported a reduced libido. There was no change in the median cycle length (28 days) or days of bleeding (5) but there was a wider variability of cycle length (p = 0.01) and a 1 day median decrease in the minimum (p < 0.0001) and maximum (p = 0.009) cycle length. Women reported a median 2 kg increase in self-reported weight and a 30-min increase in median weekly exercise. 517/50% of women stated that their diet was worse and 232/23% that it was better than before the pandemic. 407/40% reported working more and 169/16% were working less. Women related a significant increase in low mood (p < 0.0001), poor appetite (p < 0.0001), binge eating (p < 0.0001), poor concentration (p < 0.0001), anxiety (p < 0.0001), poor sleep (p < 0.0001), loneliness (p < 0.0001) and excess alcohol use (p < 0.0001). Specific stressors reported included work stress (499/48%), difficulty accessing healthcare (254/25%), change in financial (201/19%) situation, difficulties with home schooling (191/19%) or childcare (99/10%), family or partner conflict (170/16%), family illness or bereavement (156/15%).

CONCLUSIONS

The COVID-19 pandemic has significantly impacted the reproductive health of women. The long term health implications of this are yet to be determined and future studies should address this.

Gestational Stress Augments Postpartum β-Amyloid Pathology and Cognitive Decline in a Mouse Model of Alzheimer's Disease

Besides well-known risk factors for Alzheimer's disease (AD), stress, and in particular noise stress (NS), is a lifestyle risk factor common today. It is known that females are at a significantly greater risk of developing AD than males, and given that stress is a common adversity in females during pregnancy, we hypothesized that gestational noise exposure could exacerbate the postpartum development of the AD-like neuropathological changes during the life span. Pregnant APPNL-G-F/NL-G-F mice were randomly assigned to either the stress condition or control group. The stress group was exposed to the NS on gestational days 12-16, which resulted in a markedly higher hypothalamic-pituitary-adrenal (HPA) axis responsivity during the postpartum stage. Higher amyloid-β (Aβ) deposition and larger Aβ plaque size in the olfactory area were the early onset impacts of the gestational stress (GS) seen at the age of 4 months. This pattern of increased Aβ aggregation and larger plaque size were observed in various brain areas involved in both AD and stress regulation, especially in limbic structures, at the age of 6 months. The GS also produced anxiety-like behavior, deficits in learning and memory, and impaired motor coordination. The findings suggest that environmental stresses during pregnancy pose a potential risk factor in accelerating postpartum cognitive decline and AD-like neuropathological changes in the dams (mothers) later in life.

Role of the superior ovarian nerve in the regulation of follicular development and steroidogenesis in the morning of diestrus 1

PURPOSE

Little is known about the role of the superior ovarian nerve (SON) in follicular development during the estrus cycle. The aim of the present study was to analyze the role of neural signals arriving through the SON at the ovaries in the regulation of follicular development and ovarian steroid secretion in diestrus 1 of cyclic rats.

METHODS

Cyclic rats were subjected to left, right, or bilateral SON sectioning or to unilateral or bilateral laparotomy at diestrus 1 at 11:00 h. Animals were sacrificed 24 h after surgery.

RESULTS

Compared to laparotomized animals, unilateral SON sectioning decreased the number of preovulatory follicles, while bilateral SON sectioning resulted in a decreased number of atretic preantral follicles. An important observation was the presence of invaginations in the follicular wall of large antral and preovulatory follicles in animals with denervation. Furthermore, left SON sectioning increased progesterone levels but decreased testosterone levels, which are effects that were not observed in animals that were subjected to right denervation.

CONCLUSIONS

At 11:00 h of diestrus 1, the SON was found to stimulate follicle development, possibly via neural signals, such as noradrenaline and/or vasoactive intestinal peptide, and this stimulation induced the formation of follicle-stimulating hormone receptors. The role of the SON in the regulation of ovarian steroid secretion is asymmetric: the left SON inhibits the regulation of progesterone and stimulates testosterone secretion, and the right nerve does not participate in these processes.

VIP activates primordial follicles of rat through ERK-mTOR pathway in tissue culture

In vitro activation of primordial follicles is becoming more essential in assisted reproductive technologies. Vasoactive intestinal peptide (VIP) is one of the members of the neurotrophin family which has demonstrated to have an impact on follicle development in recent years. This study aims to investigate the effect of VIP on the activation of primordial follicles in neonatal rat in an in vitro culture system and to determine the relevant molecular mechanism of their activation. Ovaries of 4-day-old rats were examined for the expression of VIP receptors and were cultured in mediums containing VIP with or without inhibitors of the ERK–mTOR signalling pathway. They were then collected for histological analysis or measurement of the molecular expression of this pathway. The receptors of VIP were found in granular cells and oocytes of primordial and early-growing follicles in neonatal ovary. The ratio of growing follicle increased in the presence VIP at different concentrations, with the highest level of increase being observed in the 10⁻⁷ mol/L VIP-treated group. The ratio of PCNA-positive granular cells was also increased, while that of the apoptotic oocytes were decreased, and protein analysis showed increased phosphorylation of ERK1/2, mTOR and RPS6 in the VIP-treated group. However, the effect of VIP on the activation of primordial follicle became insignificant with the addition of MEK inhibitor (U0126) or mTORC1 inhibitor (rapamycin). This study indicated that VIP could activate neonatal rat primordial follicle through the ERK-mTOR signalling pathway, suggesting a strategy for in vitro primordial follicle recruitment.

In rats with estradiol valerate-induced polycystic ovary syndrome, the acute blockade of ovarian β-adrenoreceptors improve ovulation

BACKGROUND

Polycystic ovary syndrome is characterized by hyperactivity of the ovarian sympathetic nervous system, increases in the content and release of norepinephrine, as well as decreases in the number of β-adrenoreceptors. In the present study, β-adrenoreceptors in the ovaries of rats with polycystic ovary syndrome were blocked and analyzed the resultant effects on ovulation, hormone secretion and the enzymes responsible for the synthesis of catecholamines.

METHODS

At 60 days of age, vehicle or estradiol valerate-treated rats were injected with propranolol [10^- 4 M] into the ovarian bursas on oestrus day. The animals were sacrificed on the next day of oestrus, and the ovulation response, the steroid hormone levels in the serum and the immunoreactivity of tyrosine hydroxylase and dopamine β-hydroxylase in the ovaries were measured.

RESULTS

In animals with the induction of polycystic ovary syndrome and β-adrenoreceptor blocking, ovulation was restored in more than half of the animals and resulted in decreased hyperandrogenism with respect to the levels observed in the estradiol valerate-treated group. Tyrosine hydroxylase and dopamine β-hydroxylase were present in the theca cells of the growing follicles and the interstitial gland. Injection of propranolol restored the tyrosine hydroxylase and ovarian dopamine β-hydroxylase levels in rats with polycystic ovary syndrome induction.

CONCLUSIONS

The results suggest that a single injection into the ovarian bursas of propranolol, a nonselective antagonist of β-adrenoreceptor receptors, decreases the serum testosterone concentration and the formation of ovarian cysts, improving the ovulation rate that accompanies lower levels of tyrosine hydroxylase and dopamine β-hydroxylase in the ovary.

Stress, female reproduction and pregnancy

Stress is one of the commonest and underappreciated causes of reproductive frailty in women. The stress system leads to adaptive responses via mobilization of hormonal systems. Adaptability and resistance to stress are fundamental to life. The response to stressors depends on the type of stressor, the timing and duration of stress, the genetic predisposition, personality characteristics, and the way of coping with stress. The hypothalamic-pituitary-adrenal (HPA) axis has a direct inhibitory action on the hypothalamic-pituitary-ovarian (HPO) axis at multiple levels. Acute and chronic stress impairs reproduction, eventually acting on varying mechanisms. Undernutrition, over-training, and psychological stress contribute to hypothalamic amenorrhea via reduced HPO activity. In utero stress exposure is a significant predictor of subsequent adult telomere length. Some of the metabolic consequences of intrauterine growth restriction can be mitigated by ensuring early appropriate catch-up growth, while avoiding excessive weight gain if relative hypercortisolism is not installed. The effect of maternal stress on fetuses regarding fetal HPA axis responsiveness (increased or decreased) remains under investigation. Maternal stress and depression are associated with structural and functional changes of brain parts such as hippocampus. In utero stress modifies epigenetically components of the HPA axis which can be transmitted transgenerationally.

Early transcriptional response of human ovarian and fallopian tube surface epithelial cells to norepinephrine

Evidence from human and animal studies suggests that chronic behavioral stress and resulting activation of the sympathetic nervous system may influence initiation and progression of tumors. However, the underlying mechanisms for these observations are poorly understood. The purpose of this study is to explore the effects of adrenergic signaling on cell line models derived from normal cells presumed to originate epithelial ovarian cancers. Here we explored the effects of the stress-related hormone, norepinephrine, on the transcriptional program of normal immortalized ovarian (iOSE) and fallopian tube (iFTSEC) surface epithelial cells. Analysis of RNA-Seq data of treated and untreated cells revealed a significant overlap between the responses in iOSE and iFTSEC cells. Most genes modulated by norepinephrine in ovarian and fallopian tube epithelial cells are already expressed in normal ovarian and fallopian tissue and cells. For several genes, expression changes were reflected at the protein level. Genes in immune-related and developmental pathways were enriched in the set of genes modulated by norepinephrine. We identified HOXA5, SPIB, REL, SRF, SP1, NFKB1, MEF2A, E2F1, and EGR1 transcription factor binding sites to be highly enriched in our dataset. These data represent the early transcriptional response to norepinephrine in cells postulated to originate epithelial ovarian cancer.

Prolactin modulates luteal activity in the short-nosed fruit bat, Cynopterus sphinx during delayed embryonic development

The aim of this study was to evaluate the role of prolactin as a modulator of luteal steroidogenesis during the period of delayed embryonic development in Cynopterus sphinx. A marked decline in circulating prolactin levels was noted during the months of November through December coinciding with the period of decreased serum progesterone and delayed embryonic development. The seasonal changes in serum prolactin levels correlated positively with circulating progesterone (P) level, but inversely with circulating melatonin level during first pregnancy showing delayed development in Cynopterus sphinx. The results also showed decreased expression of prolactin receptor-short form (PRL-RS) both in the corpus luteum and in the utero-embryonic unit during the period of delayed embryonic development. Bats treated in vivo with prolactin during the period of delayed development showed significant increase in serum progesterone and estradiol levels together with significant increase in the expression of PRL-RS, luteinizing hormone receptor (LH-R), steroidogenic acute receptor protein (STAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) in the ovary. Prolactin stimulated ovarian angiogenesis (vascular endothelial growth factor) and cell survival (B-cell lymphoma 2) in vivo. Significant increases in ovarian progesterone production and the expression of prolactin-receptor, LH-R, STAR and 3β-HSD proteins were noted following the exposure of LH or prolactin in vitro during the delayed period. In conclusion, short-day associated increased melatonin level may be responsible for decreased prolactin release during November-December. The decline in prolactin level might play a role in suppressing P and estradiol-17β (E2) estradiol levels thereby causing delayed embryonic development in C. sphinx.

In vivo blockade of acetylcholinesterase increases intraovarian acetylcholine and enhances follicular development and fertility in the rat

Growth and differentiation of ovarian follicles are regulated by systemic and local factors, which may include acetylcholine (ACh). Granulosa cells (GCs) of growing follicles and luteal cells produce ACh and in cultured GCs it exerts trophic actions via muscarinic receptors. However, such actions were not studied in vivo. After having established that rat ovarian GCs and luteal cells express the ACh-metabolizing enzyme ACh esterase (AChE), we examined the consequences of local application of an AChE inhibitor, huperzine A (HupA), by osmotic minipump delivery into the ovarian bursa of hemiovariectomized rats. Saline was used in the control group. Local delivery of HupA for 4 weeks increased ovarian ACh content. Estrus cyclicity was not changed indicating a locally restricted range of HupA action. The number of primordial and primary follicles was unaffected, but small secondary follicles significantly increased in the HupA group. Furthermore, a significant increase in the number of corpora lutea suggested increased ovulatory events. In support, as shown upon mating, HupA-treated females had significantly increased implantation sites and more pups. Thus the data are in support of a trophic role of ACh in follicular development and ovulation and point to an important role of ACh in female fertility.

Follicular fluid norepinephrine and dopamine concentrations are higher in polycystic ovary syndrome

The aim of the present study was to compare follicular fluid (FF) levels of norepinephrine (NE) and dopamine (DA) in polycystic ovary syndrome (PCOS) and non-PCOS patients who underwent in vitro fertilization (IVF). Forty-seven PCOS patients (study group) and 61 patients with male factor infertility (control group) who underwent IVF using GnRH agonist protocol were recruited. Concentrations of NE and DA were measured in FF specimens of all patients. Demographic characteristics were comparable between the groups. Significantly higher levels of NE were measured in FF of PCOS patients (median: 61.05 nmol/l) compared to those with male infertility (median: 49.82 nmol/l). Similarly, significantly higher levels of DA were measured in FF of PCOS patients (median: 23.70 nmol/l) compared to those with male infertility (median: 18.28 nmol/l). In conclusion, the FF concentrations of both catecholamine are increased in PCOS patients when compared to non-PCOS patients.

A Follicle Rupture Assay Reveals an Essential Role for Follicular Adrenergic Signaling in Drosophila Ovulation

Ovulation is essential for the propagation of the species and involves a proteolytic degradation of the follicle wall for the release of the fertilizable oocyte. However, the precise mechanisms for regulating these proteolytic events are largely unknown. Work from our lab and others have shown that there are several parallels between Drosophila and mammalian ovulation at both the cellular and molecular levels. During ovulation in Drosophila, posterior follicle cells surrounding a mature oocyte are selectively degraded and the residual follicle cells remain in the ovary to form a corpus luteum after follicle rupture. Like in mammals, this rupturing process also depends on matrix metalloproteinase 2 (Mmp2) activity localized at the posterior end of mature follicles, where oocytes exit. In the present study, we show that Mmp2 activity is regulated by the octopaminergic signaling in mature follicle cells. Exogenous octopamine (OA; equivalent to norepinephrine, NE) is sufficient to induce follicle rupture when isolated mature follicles are cultured ex vivo, in the absence of the oviduct or ovarian muscle sheath. Knocking down the alpha-like adrenergic receptor Oamb (Octoampine receptor in mushroom bodies) in mature follicle cells prevents OA-induced follicle rupture ex vivo and ovulation in vivo. We also show that follicular OA-Oamb signaling induces Mmp2 enzymatic activation but not Mmp2 protein expression, likely via intracellular Ca²⁺ as the second messenger. Our work develops a novel ex vivo follicle rupture assay and demonstrates the role for follicular adrenergic signaling in Mmp2 activation and ovulation in Drosophila, which is likely conserved in other species.

Ovulation is the process of releasing fertilizable oocytes from the ovary and is essential for metazoan reproduction. Our recent work has demonstrated principles governing ovulation process that are highly conserved across species, such that both mammals and Drosophila utilize matrix metalloproteinase (Mmp) to degrade extracellular matrix and weaken the follicle wall for follicle rupture. However, a fundamental question remaining in the field is how Mmp activity is precisely regulated during ovulation. This paper reports that Drosophila octopamine (OA), the insect equivalent of norepinephrine (NE), is the signal to induce Mmp activity through activating its receptor Oamb on mature follicle cells and that this may induce ovulation. These findings allow us to develop the first ex vivo follicle rupture assay for Drosophila, which gives us unprecedented ability to characterize the entire follicle rupturing process ex vivo and to identify essential factors for ovulation. Furthermore, we show that NE partially fulfills OA’s role in inducing follicle rupture ex vivo, indicating that follicular adrenergic signal is a conserved signal to regulating Mmp activity and ovulation. Our work not only sheds light on the long-standing question of Mmp regulation, but also may lead to a better understanding of Mmp and NE linked pathological processes including cancer metastasis and polycystic ovary syndrome.

Neonatal testosterone exposure induces early development of follicular cysts followed by sympathetic ovarian hyperinnervation

This study analysed the temporal association between ovarian cyst development induced by neonatal androgenisation and sympathetic innervation. Neonatal rats (postnatal Days 1 to 5) were treated with testosterone or dihydrotestosterone and the effects were evaluated at postnatal Days 20, 40, 90 or 180. Ovulation rate, number of cystic follicles and density of sympathetic fibres were analysed. The effects of surgical denervation or gonadotrophin stimulation were also assessed. Rats exposed to testosterone showed no oestrous cycle activity and did not ovulate, maintaining a polycystic ovarian morphology at all ages studied. Also, a significant increase in ovarian density of noradrenergic fibres was detected at postnatal Days 90 and 180. Sympathectomy was unable to re-establish ovarian activity; however, human chorionic gonadotrophin stimulation was enough to induce ovulation. The impact of dihydrotestosterone on ovarian function was less noticeable, showing the coexistence of corpora lutea and cystic structures without changes in sympathetic innervation. Our findings suggest that a remodelling of ovarian sympathetic innervation occurs as a response to modifications in the pattern of follicular growth induced by testosterone. A role of sympathetic innervation in the maintenance of the polycystic condition is suggested.

Asymmetric steroidogenic response by the ovaries to the vasoactive intestinal peptide

In vitro the vasoactive intestinal peptide (VIP) stimulates progesterone, androgens, and estradiol secretion, and the effects are time-dependent. The present study analyzed the acute (1 h) and sub-acute (24 h) effects of unilateral injection of VIP into the ovarian bursa on each day of the estrous cycle on progesterone, testosterone, and estradiol serum levels. Cyclic 60-day-old virgin female rats on diestrus-1, diestrus-2, proestrus, or estrus were injected with saline or VIP 10(-6) M into the left or right ovarian bursa. One hour after saline injection on each day of estrus cycle, progesterone levels were higher than in control animals. The acute effects of saline solution on testosterone and estradiol levels were asymmetric and varied during the estrous cycle. In comparison with saline groups, the effects of VIPergic stimulation on progesterone, testosterone, and estradiol serum levels depend on the time elapsed between treatment and autopsy and vary during the estrous cycle. An acute asymmetric response from the ovaries to the VIP was observed at diestrus-1, diestrus-2, and proestrus on progesterone and estradiol levels. The asymmetries on testosterone levels were observed at diestrus-1, diestrus-2, and estrus days. The present results suggest that in the cyclic rat, each ovary has different sensitivities to VIPergic stimulation which depends on the endocrine status of the animal.

Expression of the beta-2 adrenergic receptor (ADRB-2) in human and monkey ovarian follicles: a marker of growing follicles?

Background

ADRB-2 was implicated in rodent ovarian functions, including initial follicular growth. In contrast, ADRB-2 expression and function in nonhuman primate and human ovary were not fully known but innervation and significant levels of norepinephrine (NE), which is a ligand at the ADRB-2, were reported in the ovary.

Methods

We studied expression of ADRB-2 in human and rhesus monkey ovary (RT-PCR, immunohistochemistry; laser micro dissection) and measured levels of norepinephrine (NE; ELISA) in monkey follicular fluid (FF). 3D cultures of monkey follicles (4 animals) were exposed to NE or the ADRB-2 agonist isoproterenol (ISO), and follicular development (size) was monitored. Upon termination expression of ADRB-2, FSH receptor and aromatase genes were examined.

Results

Immunohistochemistry and RT-PCR of either human follicular granulosa cells (GCs) obtained by laser micro dissection or isolated monkey follicles revealed ADRB-2 in GCs of primordial, primary, secondary and tertiary follicles. Staining of GCs in primordial and primary follicles was intense. In large preantral and antral follicles the staining was heterogeneous, with positive and negative GCs present but GCs lining the antrum of large follicles were generally strongly immunopositive. Theca, interstitial, and ovarian surface epithelial cells were also positive. NE was detected in FF of preovulatory antral monkey follicles (0.37 + 0.05 ng/ml; n = 7; ELISA) but not in serum. We examined preantral follicles ranging from 152 to 366 μm in diameter in a 3D culture in media supplemented with follicle stimulating hormone (FSH). Under these conditions, neither NE, nor ISO, influenced growth rate in a period lasting up to one month. Upon termination of the cultures, all surviving follicles expressed aromatase and FSH receptors, but only about half of them also co-expressed ADRB-2. The ADRB-2 expression was not correlated with the treatment but was positively correlated with the follicular size at the beginning and at the end of the culture period. Hence, expression of ADRB-2 was found in the largest and fastest-in vitro growing follicles.

Conclusions

The results imply ADRB-2-mediated actions in the development of primate follicles. Drugs interfering with ADRB-2 are used to treat medical conditions and may have unexplored effects in the human ovary.

Transcriptional profiling of five isolated size-matched stages of human preantral follicles

Little is known of the early stages of human follicular development and the complex processes that regulate follicular growth. To identify genes of potential importance, we analysed follicle-related transcripts in five populations of isolated size-matched human preantral follicles by microarray analysis. Oocyte-specific genes were found to be the most abundant and differentially expressed transcripts and included germ cell transcription factors LHX8 and SOHLH2 which were significantly down-regulated during preantral follicle development. Differentially expressed genes also included transcription factors of NOTCH signalling, IGF2, orphan nuclear receptor LRH-1, and homeobox gene HOXA7, indicating potentially important regulatory roles for these genes during early human folliculogenesis. We also found that FSHR mRNA and protein were present in the earliest stages of preantral follicles, whereas LHR was absent. In conclusion, our data identify specific oocyte and somatic genes in small human follicles that impact early follicle growth, and provide foundation for further analysis of the signalling pathways involved in early human folliculogenesis.

The effects of sensorial denervation on the ovarian function, by the local administration of capsaicin, depend on the day of the oestrous cycle when the treatment was performed

There is evidence that sensory innervation plays a role in the regulation of puberty. The present study investigates the effects of functional sensorial desensitisation induced by capsaicin administration to adult female rats in the days of diestrus 1, diestrus 2, pro-oestrus or oestrus on ovulation and serum oestradiol and progesterone concentration. The animals were allotted at random to one of the following groups: (1) animals with capsaicin administration into the bursa ovarica (local administration) (2) animals with vehicle administration into the bursa ovarica and (3) untreated animals group. The animals treated were killed on the day of oestrus after three consecutive 4-day oestrous cycles. No differences were observed in oestrous cyclicity or the average number of ova shed between the sensorial desensitisation animals and the vehicle-treated groups. Capsaicin administration resulted in a significant increase in the intra-ovarian noradrenaline levels in the day of diestrus 2 and pro-oestrus. Serum oestradiol and progesterone concentrations were different, depending on the day of the oestrous cycle in which the treatment was performed. These results suggest that in adult normal female rats, ovarian sensorial innervations participate together with the sympathetic innervation in the ovarian function regulating the hormone secretion and this participation varies along the oestrous cycle.

Stress and the reproductive axis

There exists a reciprocal relationship between the hypothalamic-pituitary-adrenal (HPA) and the hypothalamic-pituitary-gonadal (HPG) axes, wherein the activation of one affects the function of the other and vice versa. For example, both testosterone and oestrogen modulate the response of the HPA axis, whereas activation of the stress axis, especially activation that is repeating or chronic, has an inhibitory effect upon oestrogen and testosterone secretion. Alterations in maternal care can produce significant effects on both HPG and HPA physiology, as well as behaviour in the offspring at adulthood. For example, changes in reproductive behaviour induced by altered maternal care may alter the expression of sex hormone receptors such as oestrogen receptor (ER)α that govern sexual behaviour, and may be particularly important in determining the sexual strategies utilised by females. Stress in adulthood continues to mediate HPG activity in females through activation of a sympathetic neural pathway originating in the hypothalamus and releasing norepinephrine into the ovary, which produces a noncyclic anovulatory ovary that develops cysts. In the opposite direction, sex differences and sex steroid hormones regulate the HPA axis. For example, although serotonin (5-HT) has a stimulatory effect on the HPA axis in humans and rodents that is mediated by the 5-HT1A receptor, only male rodents respond to 5-HT1A antagonism to show increased corticosterone responses to stress. Furthermore, oestrogen appears to decrease 5-HT1A receptor function at presynaptic sites, yet increases 5-HT1A receptor expression at postsynaptic sites. These mechanisms could explain the heightened stress HPA axis responses in females compared to males. Studies on female rhesus macaques show that chronic stress in socially subordinate female monkeys produces a distinct behavioural phenotype that is largely unaffected by oestrogen, a hyporesponsive HPA axis that is hypersensitive to the modulating effects of oestrogen, and changes in 5-HT1A receptor binding in the hippocampus and hypothalamus of social subordinate female monkeys that are restored or inverted by oestrogen replacement. This review summarises all of these studies, emphasising the profound effect that the interaction of the reproductive and stress axes may have on human reproductive health and emotional wellbeing.

Long-term effects of early-life exposure to environmental oestrogens on ovarian function: role of epigenetics

Oestrogens play an important role in development and function of the brain and reproductive tract. Accordingly, it is considered that developmental exposure to environmental oestrogens can disrupt neural and reproductive tract development, potentially resulting in long-term alterations in neurobehaviour and reproductive function. Many chemicals have been shown to have oestrogenic activity, whereas others affect oestrogen production and turnover, resulting in the disruption of oestrogen signalling pathways. However, these mechanisms and the concentrations required to induce these effects cannot account for the myriad adverse effects of environmental toxicants on oestrogen-sensitive target tissues. Hence, alternative mechanisms are assumed to underlie the adverse effects documented in experimental animal models and thus could be important to human health. In this review, the epigenetic regulation of gene expression is explored as a potential target of environmental toxicants including oestrogenic chemicals. We suggest that toxicant-induced changes in epigenetic signatures are important mechanisms underlying the disruption of ovarian follicular development. In addition, we discuss how exposure to environmental oestrogens during early life can alter gene expression through effects on epigenetic control potentially leading to permanent changes in ovarian physiology.

Human testicular peritubular cells host putative stem Leydig cells with steroidogenic capacity

AIM

We aim to examine the steroidogenic phenotype and the differentiation potential of human testicular peritubular cells (HTPCs) and to explore their possible relationship to the adult Leydig cell lineage.

BACKGROUND

The cells of the adult Leydig cell lineage may reside in the peritubular compartment of the testis. This suggestion is supported by the facts that the rodent peritubular cells can be differentiated toward this lineage and that cAMP enhances their steroidogenic potential.

METHODS

Human testicular biopsies, and derived HTPCs, were analyzed by immunohistochemistry, RT-PCR, and Western blotting. After stimulation by forskolin or platelet-derived growth factor-BB, quantitative RT-PCR was used to compare the levels of mRNAs encoding proteins involved in steroidogenesis and steroid production was analyzed by liquid chromatography and tandem mass spectrometry.

RESULTS

Immunohistochemical analysis revealed that the peritubular cells that form the outer part of the tubular wall express platelet derived growth factor receptor-α. Furthermore, the pluripotency markers (POU domain class 5 transcription factor 1, GATA-binding protein 4), stem Leydig cell markers (platelet derived growth factor receptor-A, leukemia inhibitory factor receptor), and mRNAs encoding proteins involved in steroidogenesis (nuclear receptor subfamily 5, group A, member 1; steroidogenic acute regulatory protein; CYP11A1; CYP17A1; 3β-hydroxysteroid dehydrogenase) were expressed by the HTPCs. Stimulation with forskolin increased the expression of the steroidogenic markers, which was accompanied by the production of pregnenolone and progesterone by HTPCs in vitro. Treatment with platelet-derived growth factor-BB induced expression of steroidogenic acute regulatory protein.

CONCLUSIONS

Our results indicate that the tubular wall of the human testis is a reservoir for cells of the adult Leydig cell lineage and that the steroidogenic potential of these cells can be activated in culture.

Lack of sensorial innervation in the newborn female rats affects the activity of hypothalamic monoaminergic system and steroid hormone secretion during puberty

There is evidence that sensory innervation plays a role regulating ovarian functions, including fertility.Since sensory denervation by means of capsaicin in newborn female rats results in a lower response togonadotropins, the present study analyzed the effects that sensory denervation by means of capsaicin in neonatal rats has on the concentration of monoamines in the anterior(AH) and medium (MH) hypothalamus, and on steroid hormone levels in serum. Groups of newborn female rats were injected subcutaneously with capsaicin and killed at 10, 20, and 30 days of age and on the first vaginal estrous.The concentrations of noradrenaline, dopamine, serotonin(5-HT), and their metabolites in the AH and MH were measured using HPLC, and the levels of estradiol (E),progesterone (P), testosterone (T), FSH, and luteinizing hormone using radioimmunoanalysis. The results show thatat 20 days of age, capsaicin-treated rats have lowernoradrenergic and serotonergic activities in the AH, and that the dopaminergic activity was lower in the MH. These results suggest that the sensorial system connections within the monoaminergic systems of the AH and MH are different.Capsaicin-treated animals had lower T, E, and P levels than in the control group, suggesting that the lower activity in the AH monoaminergic system and lower hormonesecretion could be explained by the blockade of information mediated by the sensory innervation (probably substance P), mainly between the ovary and the AH.

Norepinephrine stimulates progesterone production in highly estrogenic bovine granulosa cells cultured under serum-free, chemically defined conditions

BACKGROUND

Since noradrenergic innervation was described in the ovarian follicle, the actions of the intraovarian catecholaminergic system have been the focus of a variety of studies. We aimed to determine the gonadotropin-independent effects of the catecholamine norepinephrine (NE) in the steroid hormone profile of a serum-free granulosa cell (GC) culture system in the context of follicular development and dominance.

METHODS

Primary bovine GCs were cultivated in a serum-free, chemically defined culture system supplemented with 0.1% polyvinyl alcohol. The culture features were assessed by hormone measurements and ultrastructural characteristics of GCs.

RESULTS

GCs produced increasing amounts of estradiol and pregnenolone for 144h and maintained ultrastructural features of healthy steroidogenic cells. Progesterone production was also detected, although it significantly increased only after 96h of culture. There was a highly significant positive correlation between estradiol and pregnenolone production in high E2-producing cultures. The effects of NE were further evaluated in a dose-response study. The highest tested concentration of NE (10 (-7) M) resulted in a significant increase in progesterone production, but not in estradiol or pregnenolone production. The specificity of NE effects on progesterone production was further investigated by incubating GCs with propranolol (10 (-8) M), a non-selective beta-adrenergic antagonist.

CONCLUSIONS

The present culture system represents a robust model to study the impact of intrafollicular factors, such as catecholamines, in ovarian steroidogenesis and follicular development. The results of noradrenergic effects in the steroidogenesis of GC have implications on physiological follicular fate and on certain pathological ovarian conditions such as cyst formation and anovulation.

Convergence of multiple mechanisms of steroid hormone action

Steroid hormones modulate a wide array of physiological processes including development, metabolism, and reproduction in various species. It is generally believed that these biological effects are predominantly mediated by their binding to specific intracellular receptors resulting in conformational change, dimerization, and recruitment of coregulators for transcription-dependent genomic actions (classical mechanism). In addition, to their cognate ligands, intracellular steroid receptors can also be activated in a "ligand-independent" manner by other factors including neurotransmitters. Recent studies indicate that rapid, nonclassical steroid effects involve extranuclear steroid receptors located at the membrane, which interact with cytoplasmic kinase signaling molecules and G-proteins. The current review deals with various mechanisms that function together in an integrated manner to promote hormone-dependent actions on the central and sympathetic nervous systems.

Role of nerve growth factor (NGF) and its receptors in folliculogenesis

Summary Nerve growth factor (NGF) is a prototype member of the neurotrophins family and has important functions in the maintenance of viability and proliferation of neuronal and non-neuronal cells, such as certain ovarian cells. The present review highlights the role of NGF and its receptors on ovarian follicle development. NGF initiates its multiple actions through binding to two classes of receptors: the high affinity receptor tyrosine kinase A (TrkA) and the low-affinity receptor p75. Different intracytoplasmic signalling pathways may be activated through binding to NGF due to variation in the receptors. The TrkA receptor activates predominantly phosphatidylinositol-3-kinase (PI3K) and mitogenic activated protein kinase (MAPK) to promote cell survival and proliferation. The activation of the phospholipase type Cγ (PLCγ) pathway, which results in the production of diacylglycerol (DAG) and inositol triphosphate (IP3), culminates in the release of calcium from the intracytoplasmic cellular stocks. However, the details of activation through p75 receptor are less well known. Expression of NGF and its receptors is localized in ovarian cells (oocyte, granulosa, theca and interstitial cells) from several species, which suggests that NGF and its receptors may regulate some ovarian functions such as follicular survival or development. Thus, the use of NGF in culture medium for ovarian follicles may be of critical importance for researchers who want to promote follicular development in vitro in the future.

Vasoactive intestinal peptide and its receptors in human ovarian cortical follicles

BACKGROUND

Ovarian cryopreservation is one option for fertility preservation in patients with cancer. The danger of reseeding malignancies could be eliminated by in vitro maturation of primordial follicles from the frozen-thawed tissue. However, the development of this system is hindered by uncertainties regarding factors that activate primordial follicles. Neuronal growth factors such as vasoactive intestinal peptide (VIP) play important roles in early mammalian folliculogenesis. There are no data on the expression of VIP and its vasoactive intestinal peptide pituitary adenylate cyclase 1 and 2 receptors (VPAC1-R and VPAC2-R) in human preantral follicles.

METHODOLOGY/PRINCIPAL FINDINGS

Tissue samples from 14 human fetal ovaries and 40 ovaries from girls/women were prepared to test for the expression of VIP, VPAC1-R, and VPAC2-R on the protein (immunohistochemisty) and mRNA (reverse transcription polymerase chain reaction) levels. Immunohistochemistry staining was mostly weak, especially in fetal samples. The VIP protein was identified in oocytes and granulosa cells (GCs) in the fetal samples from 22 gestational weeks (GW) onwards. In girls/women, VIP follicular staining (oocytes and GCs) was identified in 45% of samples. VPAC1-R protein was identified in follicles in all fetal samples from 22GW onwards and in 63% of the samples from girls/women (GC staining only in 40%). VPAC2-R protein was identified in follicles in 33% of fetal samples and 47% of the samples from girls/women. The mRNA transcripts for VIP, VPAC1-R, and VPAC2-R were identified in ovarian extracts from fetuses and women.

CONCLUSIONS

VIP and its two receptors are expressed in human ovarian preantral follicles. However, their weak staining suggests they have limited roles in early follicular growth. To elucidate if VIP activates human primordial follicles, it should be added to the culture medium.

Norepinephrine, active norepinephrine transporter, and norepinephrine-metabolism are involved in the generation of reactive oxygen species in human ovarian granulosa cells

The neurotransmitter norepinephrine (NE) is derived from the sympathetic nervous system and may be involved in the regulation of ovarian functions. Ovarian innervation increases in patients with polycystic ovarian syndrome (PCOS), prompting us to readdress a role of NE in the human ovary. In vitro fertilization-derived granulosa cells (GC), follicular fluids (FF), and ovarian sections were studied. NE was found in FF and freshly isolated GC, yet significantly lower levels of NE were detected in samples from PCOS patients. Furthermore, the metabolite normetanephrine was detected in FF. Together this suggests cellular uptake and metabolism of NE in GC. In accordance, the NE transporter and NE-metabolizing enzymes [catechol-o-methyltransferase (COMT) and monoamine oxidase A] were found in GC, COMT in GC and thecal cells of large human antral follicles in vivo and in cultured GC. Cellular uptake and metabolism of NE also occurred in cultured GC, events that could be blocked pharmacologically. NE, in the range present in FF, is unlikely to affect GC via activation of typical α- or β-receptors. In line with this assumption, it did not alter phosphorylation of MAPK. However, NE robustly induced the generation of reactive oxygen species (ROS). This action occurred even when receptors were blocked but was prevented by blockers of NE transporter, COMT, and monoamine oxidase A. Thus, NE contributes to the microenvironment of preovulatory human follicles and is lower in PCOS. By inducing the production of ROS in GC, NE is linked to ROS-regulated events, which are emerging as crucial factors in ovarian physiology, including ovulation.

Role of PACAP in Female Fertility and Reproduction at Gonadal Level - Recent Advances

Pituitary adenylate cyclase activating polypeptide (PACAP) is a pleiotropic neuropeptide, first isolated from hypothalamic extracts, but later shown in peripheral organs, such as endocrine glands, gastrointestinal system, cardiovascular system, and reproductive organs. PACAP plays a role in fertility and reproduction. Numerous studies report on the gonadal regulatory effects of PACAP at hypothalamo-hypophyseal levels. However, the local effects of PACAP at gonadal levels are also important. The present review summarizes the effects of PACAP in the ovary. PACAP and its receptors are present in the ovary, and PACAP plays a role in germ cell migration, meiotic division, follicular development, and atresia. The autocrine-paracrine hormonal effects seem to play a regulatory role in ovulation, luteinization, and follicular atrophy. Altogether, PACAP belongs to the ovarian regulatory peptides.

In vitro and in vivo regulation of follicular formation and activation in cattle

The establishment of a stockpile of non-growing, primordial follicles and its gradual depletion through activation of primordial follicles are essential processes for female fertility. However, the mechanisms that regulate follicle formation, the activation of primordial follicles to begin growth and the primary-to-secondary follicle transition are poorly understood, especially in domestic animals and primates. The authors' laboratory is engaged in studying early stages of follicular development in cattle and this review summarises the progress to date. Bovine follicles begin to form in fetal ovaries around the beginning of the second trimester of pregnancy (about Day 90), but the first activated, primary follicles do not appear until after Day 140. Bovine fetal ovaries produce steroids and production is highest during the first trimester. In vitro, oestradiol and progesterone inhibit follicle formation and acquisition by newly formed follicles of the capacity to activate. Meiotic arrest of the oocyte in the diplotene stage of first prophase does not occur until after follicle formation and is correlated with acquisition of the capacity to activate. This may explain the gap between follicle formation and appearance of the first activated follicles. Once capacity to activate has been acquired, it seems likely that activation in vivo is controlled by the balance between stimulators and inhibitors of activation. Insulin and kit ligand stimulate and anti-Müllerian hormone (AMH) inhibits activation in vitro. Few bovine follicles transition from the primary to the secondary stage in vitro, but this transition is increased by medium supplements, testosterone and vascular endothelial growth factor (VEGF).

Hnrnpk, a protein differentially expressed in immature rat ovarian development, is required for normal primordial follicle assembly and development

The formation of ovarian follicles and subsequent development after birth are critical processes for female reproduction, and inappropriate coordination of these processes contributes to ovarian pathologies, such as premature ovarian failure and infertility. Identification and functional investigation of the factors involved in follicular assembly and the initial recruitment will be of great significance to the understanding of the female reproduction process. In this study, we examined the roles of transcription factor heterogeneous nuclear ribonucleoprotein K (Hnrnpk) in rat primordial folliculogenesis using RNA interference knockdown strategies. Reducing Hnrnpk mRNA levels via Hnrnpk small interfering RNAs to neonatal ovaries resulted in a substantial loss of naked oocytes, primordial and primary follicles. Structure disorganization of the ovary characterized by groups of oocytes arranged in nests, clusters of somatic cells not associated with any oocytes and many highly condensed oocyte nuclei was observed. Terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling assay demonstrated that these abnormalities may be partially attributable to abnormal apoptosis of oocytes. Furthermore, the microarray analysis showed that 63 genes changed significantly (≥2-folds or ≤0.5-fold) between the ovaries treated with Hnrnpk small interfering RNAs and the controls, with 22 up-regulated genes and 41 down-regulated genes. These differentially expressed genes were involved in several critical biological processes in ovarian development. These results suggest that transcription factor Hnrnpk is a key regulator for primordial follicle assembly and development, which provides a new potential therapeutic target to regulate ovarian function and treat ovarian disease.

Neonatal superior ovarian nerve transection inhibits follicle development by enhancing follicular atresia and suppressing granulosa cell proliferation in rats

The ovarian sympathetic nerves participate in the regulation of mammalian ovarian function, but it is still not known whether the neonatal ovarian sympathetic nerve is involved in follicular development and related mechanisms. In the present study, the superior ovarian nerve (SON) of the neonatal rat was transected on postnatal day (PD) 2, and follicle development, ovarian hormone secretion, ovulation rate, granulosa cell proliferation and apoptosis were analysed on PD 30 and PD 90. The results demonstrate that SON transection decreases follicle number and size, reduces ovulation induced by gonadotrophin and enhances follicular atresia. Bromodeoxyuridine (BrdU) and cleaved caspase-3 immunohistochemistry staining provide evidence that SON transection inhibits granulosa cell proliferation and promotes granulosa cell apoptosis. In addition, SON transection increases serum oestradiol levels, but has no influence on serum progesterone levels. These results suggest that the sympathetic nerve supply to the ovaries is important in regulating follicle development and ovary function. These results are critical for further understanding of the neuroendocrine regulation of ovary development and function, although the mechanism needs to be elucidated in future studies.

Effects of body condition on measures of intramuscular and rump fat, endocrine factors, and calving rate of beef cows grazing common bermudagrass or endophyte-infected tall fescue

Multiparous beef cows were managed to achieve marginal (BCS = 4.7 ± 0.07; n = 106) or good (BCS = 6.6 ± 0.06; n = 121) body condition (BC) to determine the influence of forage environment on BW and BC changes, intramuscular fat percentage (IMF), rump fat (RF), and serum hormones during 2 yr. Cows within each BC were randomly assigned to graze either common bermudagrass (CB; n = 3 pastures/yr) or toxic endophyte-infected tall fescue (EI; n = 3 pastures/yr) during a 60-d breeding season. Blood samples were collected at d 0, 30, and 60 of the breeding season, and serum concentrations of prolactin (PRL), IGF-I, and cortisol (CORT) were quantified; PRL and progesterone (P(4)) also were quantified 10 d before the breeding season (d -10). Body weight and BCS were recorded during the breeding season (d 0, 30, and 60). Cow IMF and RF were measured via ultrasonography at the start and end of the breeding season. Cows with increased (>1 ng/mL) P(4) at the beginning of the breeding season (cyclic) had greater (P < 0.02) concentrations of PRL on d 30 and 60 compared with anestrous cows. A forage environment × BC interaction tended (P = 0.07) to influence PRL. Cows grazing CB independent of BC had increased PRL compared with cows grazing EI. Prolactin was decreased in good-BC cows grazing EI compared with cows grazing CB, and cows in marginal BC grazing EI had the least concentrations of PRL. Concentrations of IGF-I were similar (P > 0.10) among good- and marginal-BC cows grazing CB, as well as good-BC cows grazing EI; however, marginal-BC cows grazing EI had reduced (P < 0.04) concentrations of IGF-I compared with all other groups. Cows in marginal BC grazing CB gained (P = 0.02) the most BW during the breeding season, whereas good-BC cows grazing EI gained the least amount of BW. Marginal-BC cows grazing CB tended (P = 0.06) to increase BC during the breeding season, whereas good-BC cows grazing either CB or EI lost BC. Rump fat tended (P = 0.07) to increase during the breeding season in marginal-BC cows compared with cows in good BC. Calving rates were similar (P > 0.10) among good- (82%) and marginal- (84%) BC cows grazing CB, and good-BC cows grazing EI (79%); however, marginal-BC cows grazing EI had a reduced (P = 0.04) calving rate (61%). Cattle grazing EI during the breeding season lost BC. That reduction in BC may be communicated to the pituitary via hormones that include IGF-I or PRL or both, resulting in decreased calving rates.

Functional expression and intracellular signaling of UTP-sensitive P2Y receptors in theca-interstitial cells

BACKGROUND

Purinergic receptors are expressed in the ovary of different species; their physiological roles remain to be elucidated. UTP-sensitive P2Y receptor activity may regulate cell proliferation. The aim of the present work was to study the functional expression of these receptors in theca/interstitial cells (TIC).

METHODS

TIC were isolated by centrifugation in a Percoll gradient. P2Y receptors and cellular markers in TIC were detected by RT-PCR and Western blot. Intracellular calcium mobilization induced by purinergic drugs was evaluated by fluorescence microscopy, phosphorylation of MAPK p44/p42 and of cAMP response element binding protein (CREB) was determined by Western blot and proliferation was quantified by [3H]-thymidine incorporation into DNA.

RESULTS

RT-PCR showed expression of p2y2r and p2y6r transcripts, expression of the corresponding proteins was confirmed. UTP and UDP, agonists for P2Y2 and P2Y6 receptors, induced an intracellular calcium increase with a maximum of more than 400% and 200% of basal level, respectively. The response elicited by UTP had an EC50 of 3.5 +/- 1.01 microM, while that for UDP was 3.24 +/- 0.82 microM. To explore components of the pathway activated by these receptors, we evaluated the phosphorylation induced by UTP or UDP of MAPK p44 and p42. It was found that UTP increased MAPK phosphorylation by up to 550% with an EC50 of 3.34 +/- 0.92 and 1.41 +/- 0.67 microM, for p44 and p42, respectively; these increases were blocked by suramin. UDP also induced p44/p42 phosphorylation, but at high concentrations. Phosphorylation of p44/p42 was dependent on PKC and intracellular calcium. To explore possible roles of this pathway in cell physiology, cell proliferation and hCG-induced CREB-phosphorylation assays were performed; results showed that agonists increased cell proliferation and prevented CREB-phosphorylation.

CONCLUSION

Here, it is shown that UTP-sensitive P2Y receptors are expressed in cultured TIC and that these receptors had the ability to activate mitogenic signaling pathways and to promote cell proliferation, as well as to prevent CREB-phosphorylation by hCG. Regulation of TIC proliferation and steroidogenesis is relevant in ovarian pathophysiology since theca hyperplasia is involved in polycystic ovarian syndrome. Purinergic receptors described might represent an important new set of molecular therapeutic targets.

Lateralization of the connections of the ovary to the celiac ganglia in juvenile rats

During the development of the female rat, a maturing process of the factors that regulate the functioning of the ovaries takes place, resulting in different responses according to the age of the animal. Studies show that peripheral innervation is one relevant factor involved.In the present study we analyzed the anatomical relationship between the neurons in the celiac-superior mesenteric ganglia (CSMG), and the right or left ovary in 24 or 28 days old female pre-pubertal rats. The participation of the superior ovarian nerve (SON) in the communication between the CSMG and the ovaries was analyzed in animals with unilateral section of the SON, previous to injecting true blue (TB) into the ovarian bursa. The animals were killed seven days after treatment. TB stained neurons were quantified at the superior mesenteric-celiac ganglia.The number of labeled neurons in the CSMG of rats treated at 28 days of age was significantly higher than those treated on day 24. At age 24 days, injecting TB into the right ovary resulted in neuron stains on both sides of the celiac ganglia; whereas, injecting the left side the stains were exclusively ipsilateral. Such asymmetry was not observed when the rats were treated at age of 28 days.In younger rats, sectioning the left SON resulted in significantly lower number of stained neurons in the left ganglia while sectioning the right SON did not modify the number of stained neurons. When sectioning of the SON was performed to 28 days old rats, no staining was observed.Present results show that the number and connectivity of post-ganglionic neurons of the CSMG connected to the ovary of juvenile female rats change as the animal mature; that the SON plays a role in this communication process as puberty approaches; and that this maturing process is different for the right or the left ovary.

Catecholamine uptake, storage, and regulated release by ovarian granulosa cells

Catecholamines present in the mammalian ovary are involved in many normal aspects of ovarian functions, including initial follicle growth, steroidogenesis, and pathological states such as polycystic ovary syndrome. Sympathetic nerve fibers are the largest source of norepinephrine (NE), but not the only one. Surgical denervation of the rat ovary reduces, but does not eliminate, the ovarian content of NE. The aim of this work was to explore which intraovarian cells may participate in the ovarian NE homeostasis and the mechanisms involved. It was found that denervated rat ovaries can take up NE and cocaine considerably, decreased its uptake, suggesting involvement of catecholamine transporters. Granulosa cells of rat ovarian follicles present dopamine transporter and NE transporter. Their functionality was confirmed in isolated rat granulosa cells while cocaine blocked the uptake of NE. Furthermore, the presence of the vesicular monoamine transporter 2, together with the exocytotic protein (synaptosome-associated protein of 25 kDa) in granulosa cells, implies catecholamine storage and regulated release. Regulated calcium-dependent release of NE was shown after depolarization by potassium, implying all neuron-like cellular machinery in granulosa cells. These results in rats may be of relevance for the human ovary because dopamine transporter, NE transporter, vesicular monoamine transporter 2, and synaptosome-associated protein of 25-kDa protein and mRNA are found in human ovarian follicles and/or isolated granulosa cells. Thus, ovarian nonneuronal granulosa cells, after taking up catecholamines, can serve as an intraovarian catecholamine-storing compartment, releasing them in a regulated way. This suggests a more complex involvement of catecholamines in ovarian functions as is currently being recognized.