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

Plasma-free metanephrines, nerve growth factor, and renalase significance in patients with PCOS

PURPOSE

Polycystic ovarian syndrome (PCOS) is a common heterogeneous condition with probably multifactorial genesis. Animal studies have proven the essential role of the sympathetic nervous system in the syndrome development, while human studies are still contradictory. The present study aims to investigate the possible influence of plasma-free metanephrine (MN), and normetanephrine (NMN), nerve growth factor (NGF), and renalase (RNL) on the hormonal and metabolic parameters in women with PCOS and healthy controls.

METHODS

Fifty patients with PCOS and 30 healthy women participated in the study. The plasma-free MN and NMN, NGF, RNL, anti-Mullerian hormone (AMH), gonadotropin, androgen levels, and metabolic parameters were investigated.

RESULTS

Plasma-free NMN and NGF concentrations were increased in PCOS individuals, while RNL levels were decreased compared to healthy volunteers. Increased plasma-free NMN (OR = 1.0213 [95%CI 1.0064-1.0364], p = 0.005) and NGF (OR = 1.0078 [95%CI 1.0001-1.0155], p = 0.046) but not MN or RNL levels were associated with a higher risk of PCOS after adjustment for age. Plasma-free NMN levels were positively associated with the LH (r = +0.253; p = 0.039). androstenedione (r = +0.265; p = 0.029), 17-OH progesterone (r = +0.285; p = 0.024), NGF (r = +0.320; p = 0.008), and AMH (r = +0.417; p < 0.001) concentrations of the investigated women. RNL levels were inversely related to the BMI (r = -0.245; p = 0.029), HOMA-IR (r = -0.250; p = 0.030), free testosterone (r = -0.303; p = 0.006) levels. systolic (r = -0.294; p = 0.008) and diastolic (r = -0.342; p = 0.002) blood pressure.

CONCLUSIONS

Increased sympathetic noradrenergic activity and NGF synthesis might be related to the increased AMH and delta-4 androgen levels in a subgroup of PCOS patients. RNL levels might influence the metabolic status of PCOS patients. Further studies are needed to explore the significance of adrenal medullar and autonomic dysfunction for developing different PCOS phenotypes and their subsequent cardiovascular complications.

Fallopian tube secreted protein affects ovarian metabolites in high grade serous ovarian cancer

High grade serous ovarian cancer (HGSOC), the most lethal histotype of ovarian cancer, frequently arises from fallopian tube epithelial cells (FTE). Once transformed, tumorigenic FTE often migrate specifically to the ovary, completing the crucial primary metastatic step and allowing the formation of the ovarian tumors after which HGSOC was originally named. As only the fimbriated distal ends of the fallopian tube that reside in close proximity to the ovary develop precursor lesions such as serous tubal intraepithelial carcinomas, this suggests that the process of transformation and primary metastasis to the ovary is impacted by the local microenvironment. We hypothesize that chemical cues, including small molecules and proteins, may help stimulate the migration of tumorigenic FTE to the ovary. However, the specific mediators of this process are still poorly understood, despite a recent growth in interest in the tumor microenvironment. Our previous work utilized imaging mass spectrometry (IMS) to identify the release of norepinephrine (NE) from the ovary in co-cultures of tumorigenic FTE cells with an ovarian explant. We predicted that tumorigenic FTE cells secreted a biomolecule, not produced or produced with low expression by non-tumorigenic cells, that stimulated the ovary to release NE. As such, we utilized an IMS mass-guided bioassay, using NE release as our biological marker, and bottom-up proteomics to demonstrate that a secreted protein, SPARC, is a factor produced by tumorigenic FTE responsible for enhancing release of ovarian NE and influencing primary metastasis of HGSOC. This discovery highlights the bidirectional interplay between different types of biomolecules in the fallopian tube and ovarian microenvironment and their combined roles in primary metastasis and disease progression.

Discovery of metabolomic biomarkers for discriminating platinum-sensitive and platinum-resistant ovarian cancer by using GC-MS

This study aims to determine ovarian cancer (OC) patients with platinum resistance for alternative treatment protocols by using metabolomic methodologies. Urine and serum samples of platinum-resistant and platinum-sensitive OC were analyzed using GC-MS. After data processing of GC-MS raw data, multivariate analyses were performed to interpret complex data for biologically meaningful information and to identify the biomarkers that cause differences between two groups. The biomarkers were verified after univariate, multivariate, and ROC analysis. Finally, metabolomic pathways related to group separations were specified. The results of biomarker analysis showed that 3,4-dihydroxyphenylacetic acid, 4-hydroxybutyric acid, L-threonine, D- mannose, and sorbitol metabolites were potential biomarkers in urine samples. In serum samples, L-arginine, linoleic acid, L-glutamine, and hypoxanthine were identified as important biomarkers. R2Y, Q2, AUC, sensitivity and specificity values of platinum-resistant and sensitive OC patients' urine and serum samples were 0.85, 0.545, 0.844, 91.30%, 81.08 and 0.570, 0.206, 0.743, 77.78%, 74.28%, respectively. In metabolic pathway analysis of urine samples, tyrosine metabolism and fructose and mannose metabolism were found to be statistically significant (p < 0.05) for the discrimination of the two groups. While 3,4-dihydroxyphenylacetic acid, L-tyrosine, and fumaric acid metabolites were effective in tyrosine metabolism. D-sorbitol and D-mannose metabolites were significantly important in fructose and mannose metabolism. However, seven metabolomic pathways were significant (p < 0.05) in serum samples. In terms of p-value, L-glutamine in the nitrogen metabolic pathway from the first three pathways; L-glutamine and pyroglutamic acid metabolites in D-glutamine and D-glutamate metabolism. In the arginine and proline metabolic pathway, L-arginine, L-proline, and L-ornithine metabolites differed significantly between the two groups.

Clinical presentation and long-term follow-up of dopamine beta hydroxylase deficiency

Dopamine beta hydroxylase (DBH) deficiency is an extremely rare autosomal recessive disorder with severe orthostatic hypotension, that can be treated with L-threo-3,4-dihydroxyphenylserine (L-DOPS). We aimed to summarize clinical, biochemical, and genetic data of all world-wide reported patients with DBH-deficiency, and to present detailed new data on long-term follow-up of a relatively large Dutch cohort. We retrospectively describe 10 patients from a Dutch cohort and 15 additional patients from the literature. We identified 25 patients (15 females) from 20 families. Ten patients were diagnosed in the Netherlands. Duration of follow-up of Dutch patients ranged from 1 to 21 years (median 13 years). All patients had severe orthostatic hypotension. Severely decreased or absent (nor)epinephrine, and increased dopamine plasma concentrations were found in 24/25 patients. Impaired kidney function and anemia were present in all Dutch patients, hypomagnesaemia in 5 out of 10. Clinically, all patients responded very well to L-DOPS, with marked reduction of orthostatic complaints. However, orthostatic hypotension remained present, and kidney function, anemia, and hypomagnesaemia only partially improved. Plasma norepinephrine increased and became detectable, while epinephrine remained undetectable in most patients. We confirm the core clinical characteristics of DBH-deficiency and the pathognomonic profile of catecholamines in body fluids. Impaired renal function, anemia, and hypomagnesaemia can be part of the clinical presentation. The subjective response to L-DOPS treatment is excellent and sustained, although the neurotransmitter profile in plasma does not normalize completely. Furthermore, orthostatic hypotension as well as renal function, anemia, and hypomagnesaemia improve only partially.

Intrafollicular and Systemic Dopamine, Noradrenaline and Adrenaline Concentrations in Cycling Mares

Simple Summary

This study provides new evidence on the physiological changes of catecholamines in follicular fluid during the follicular growth in the mare. Both dopamine and epinephrine increase in the follicular fluid with the advance of follicular development, although norepinephrine decreases. These changes could be related to the existence of systemic, autocrine and/or paracrine mechanisms of synthesis, metabolism and interconversion of catecholamines for the regulation of follicular growth and development.

Abstract

In some species, catecholamines in follicular fluid (FF) are related to local physiological events responsible for the regulation of ovarian functions and oocyte maturation. The aim of the present study was to determine and compare intrafollicular and systemic concentrations of dopamine (DA), noradrenaline (NA) and adrenaline (AD) in cycling mares. Sixty ovaries were collected during breeding season from 30 mares raised for slaughterhouse meat production, with clinically normal reproductive tracts, were evaluated. Blood samples were collected prior to slaughter. Follicles were classified into three categories in relation to size: small (20–30 mm; n = 20), medium (≥31–40 mm; n = 20) and large (≥41 mm; n = 20). Follicular fluid (FF) samples were extracted from each follicle. Intrafollicular DA, NA and AD concentrations were significantly higher than the systemic concentrations (p < 0.05). Intrafollicular DA concentrations were higher in medium than small and large follicles (p < 0.05). Intrafollicular NA concentrations were higher in small than medium and large follicles (p < 0.05). Intrafollicular AD concentrations were higher in large than small and medium follicles (p < 0.05). Follicle diameter was significantly and negatively correlated with NA and AD (p < 0.05). A significant correlation of the same hormone concentration in FF and in systemic fluid was observed (p < 0.05). In summary, the FF can serve as an intraovarian catecholamine-storing compartment, with the ability to release neurotransmitters in a regulated way. These results provide novel insights into the neuronal nature of the follicle, suggesting the involvement of catecholamines in normal ovarian functions in mares.

Effect of nervous stimulation on ovarian steroid secretion in amphibians

In the present study, the effect of nerve stimulation on the secretory activity of the ovary of adult females was analyzed for the first time in amphibians. Results revealed that in Rhinella arenarum the stimulation of nerves that supply the gonad induced an increase in estradiol and progesterone secretion, this response showing differences during the reproductive cycle of the species. During the postreproductive period, an increase in estradiol secretion was observed while, in the reproductive period, progesterone secretion increased. Our results suggest that the sympathetic division of the autonomic nervous system would be responsible for this increase, taking into account that, under our experimental conditions, acetylcholine did not affect the endocrine activity of the gonad, while adrenaline (epinephrine) was effective in inducing steroid secretion an effect that could be due to interaction with β receptors. On the other hand, our data show that the association of adrenaline with follicle-stimulating hormone increased estradiol secretion during the postreproductive period, while the association of catecholamine with LH or hCG increased progesterone secretion during the reproductive period. Our results would suggest that nerve stimulation, mediated by the release of adrenaline, would act synergistically with gonadotrophins to stimulate steroid secretion.

Analysis of Expression and Functional Activity of Aromatic L-Amino Acid Decarboxylase (DDC) and Serotonin Transporter (SERT) as Potential Sources of Serotonin in Mouse Ovary

The origin of serotonin in the ovary is the key question for understanding mechanisms of serotonergic regulation of reproductive function. We performed a study of the expression and functional activity of the serotonin transporter (SERT) and the enzyme for the synthesis of serotonin, aromatic l-amino acid decarboxylase (DDC) in mouse ovary. A pronounced peak of SERT mRNA expression occurs at the age of 14 days, but serotonin synthesis enzymes are expressed at the maximum level in the ovaries of newborn mice. SERT is detected immunohistochemically in all cellular compartments of the ovary with a maximum level of immunostaining in the oocytes of growing ovarian follicles. DDC immunolocalization, in contrast, is detected to a greater extent in primordial follicle oocytes, and decreases at the later stages of folliculogenesis. Serotonin synthesis in all cellular compartments occurs at very low levels, whereas specific serotonin uptake is clearly present, leading to a significant increase in serotonin content in the oocytes of growing primary and secondary follicles. These data indicate that the main mechanism of serotonin accumulation in mouse ovary is its uptake by the specific SERT membrane transporter, which is active in the oocytes of the growing ovarian follicles.

Imaging Mass Spectrometry Reveals Crosstalk between the Fallopian Tube and the Ovary that Drives Primary Metastasis of Ovarian Cancer

High grade serous ovarian cancer (HGSOC) is the fifth leading cause of cancer deaths among women. New evidence suggests that HGSOC arises in the fallopian tube and then colonizes the ovary before spreading into the peritoneal space. Therefore, due to the proximity of this metastasis, an experimental design was optimized using imaging mass spectrometry to capture the spatial composition of small molecules uniquely expressed when fallopian-tube-derived tumor cells were grown in the microenvironment of the ovary as a model of primary metastasis. The observed mass-to-charge ratios (m/z's) that were induced specifically in coculture represent small molecules that may contribute to the metastasis of HGSOC selectively to the ovary. Human fallopian tube epithelial HGSOC and tumorigenic murine oviductal epithelial cells, but not normal cell types, repeatedly induced a signal from the ovary at m/z 170. This signal was identified as norepinephrine, which was confirmed to stimulate invasion of ovarian cancer cells lacking wild-type p53. These molecules may reveal pathways that contribute to metastasis and biological targets for therapeutic intervention to block ovarian metastasis of fallopian-tube-derived HGSOC. The developed mass spectrometry method can be adapted to other mammalian-based model systems for investigation of untargeted metabolomics that facilitate metastasis.

Role of RFRP-3 in the development of cold stress-induced polycystic ovary phenotype in rats

RFamide-related peptide (RFRP-3) is a regulator of GnRH secretion from the brain, but it can also act in human ovary to influence steroidogenesis. We aimed to study the putative local role of RFRP-3 in the ovary and its potential participation in the development of a polycystic ovary phenotype induced by chronic sympathetic stress (cold stress). We used adult Sprague–Dawley rats divided into control and stressed groups. In both groups, we studied the effect of intraovarian exposure to RFRP-3 on follicular development and plasma ovarian steroid concentrations. We also tested the effect of RFRP-3 on ovarian steroid production in vitro. Chronic in vivo intraovarian exposure to RFRP-3 decreased basal testosterone concentrations and cold stress-induced progesterone production by the ovary. In vitro, RFRP-3 decreased hCG-induced ovarian progesterone and testosterone secretion. Immunohistochemistry and mRNA expression analysis showed a decrease in Rfrp and expression of its receptor in the ovary of stressed rats, a result which is in line with the increased testosterone levels found in stressed rats. In vivo application of RFRP-3 recovered the low levels of secondary and healthy antral follicles found in stressed rats. Taken together, our data indicate a previously unknown response of hypothalamic and ovarian RFRP-3 to chronic cold stress, influencing ovarian steroidogenesis and follicular dynamics. Thus, it is likely that RFRP-3 modulation in the ovary is a key component of development of the polycystic ovary phenotype.

Effects of sympathectomy on ovarian follicular development and steroid secretion

Recently, the influence of adrenergic activity over ovarian function, and thus fertility, has begun to gain importance. Previous studies have shown that adrenergic activity through norepinephrine (NE) participates in the control of follicular development and steroidal secretion from the ovary, among other functions. To examine this phenomenon, the denervation of the gonad has been widely used to observe changes in the ovary’s performance. Nevertheless, the effect of the absence of adrenergic nerves in the ovary has only been studied in short times periods. In the present work, we used guanethidine (a drug that produces an irreversible sympathectomy) during the infantile period of rats, and we observed its effects in the adult rat (6 months old). Our results indicate that ovarian NE content is recovered at 6 months old, alongside with an increase of the adrenal content of NE and a dysfunctional celiac ganglion. Together, these results suggest that the recovery of ovarian NE does not come from a neural origin. In addition, ovarian performance was impaired because the changes in follicular development and steroidal secretion are not recovered despite the recovery of ovarian NE content. In conclusion, these results suggest that the nerve–ovarian connections, which are established during infantile development, are necessary for the accurate response of the ovary to sympathetic stimulation.

α-SNAP is expressed in mouse ovarian granulosa cells and plays a key role in folliculogenesis and female fertility

The balance between ovarian folliculogenesis and follicular atresia is critical for female fertility and is strictly regulated by a complex network of neuroendocrine and intra-ovarian signals. Despite the numerous functions executed by granulosa cells (GCs) in ovarian physiology, the role of multifunctional proteins able to simultaneously coordinate/modulate several cellular pathways is unclear. Soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (α-SNAP) is a multifunctional protein that participates in SNARE-mediated membrane fusion events. In addition, it regulates cell-to-cell adhesion, AMPK signaling, autophagy and apoptosis in different cell types. In this study we examined the expression pattern of α-SNAP in ovarian tissue and the consequences of α-SNAP (M105I) mutation (hyh mutation) in folliculogenesis and female fertility. Our results showed that α-SNAP protein is highly expressed in GCs and its expression is modulated by gonadotropin stimuli. On the other hand, α-SNAP-mutant mice show a reduction in α-SNAP protein levels. Moreover, increased apoptosis of GCs and follicular atresia, reduced ovulation rate, and a dramatic decline in fertility is observed in α-SNAP-mutant females. In conclusion, α-SNAP plays a critical role in the balance between follicular development and atresia. Consequently, a reduction in its expression/function (M105I mutation) causes early depletion of ovarian follicles and female subfertility.

miR-21 is involved in norepinephrine-mediated rat granulosa cell apoptosis by targeting SMAD7

Substantive evidence has indicated that the sympathetic innervation contributes to the regulation and development of ovarian functions. Norepinephrine (NE) is one of the major neurotransmitters contained in the extrinsic ovarian sympathetic nerves and is thought to be a potent moderator of ovarian functions such as steroidogenesis and granulosa cell proliferation or apoptosis. However, the mechanisms of NE regulation of granulosa cell apoptosis in the rat ovary are rare. Real-time PCR and Western blot results show that NE regulates the expression of miR-21 in primary granulosa cells in a dose-dependent manner. Additionally, we found that miR-21 is involved in NE-mediated rat granulosa cells apoptosis and blocks granulosa cell apoptosis by targeting Smad7, a transforming growth factor-beta-inducible mediator of apoptosis in granulosa cells. In primary granulosa cells, a combined treatment of NE and TGF-β increased apoptosis and decreased miR-21 expression, but increased SMAD7 protein levels. We also demonstrated that NE regulates miR-21 by coupling to α_1A-adrenergic receptor (α_1A-AR). This is the first demonstration that NE controls the reproductive functions by modulating the expression of miR-21 and promoting TGF-β-induced granulosa cell apoptosis. Such NE-mediated effects could be potentially used for regulating the reproductive processes and for treating reproductive disorders.

Gestational stress, placental norepinephrine transporter and offspring fertility

Chronic cold stress produces adrenergic overload that can affect fetal development. The placental norepinephrine transporter (NET) clears norepinephrine (NE) from both maternal circulation and the fetus during gestation. If this system fails, NE clearance can be reduced, leading to high fetal exposure to NE. The main aim of this study was to determine the changes in NET expression during gestation and their relationship with the functional capacity of NET to transport NE under stressful conditions. Additionally, this study correlated these findings with the reproductive capacity of 2nd-generation progeny. Pregnant rats were subjected to chronic cold stress at 4°C for 3 h each day throughout their pregnancies. We found that exposure of pregnant rats to sympathetic stress caused the following effects: increased NE and corticosterone levels throughout pregnancy, decreased capacity of the placenta to clear NE from the fetus to the mother's circulation, altered NET protein levels depending on the sex of the fetus and increased placental and body weights of pups. For the first time, we also described the disrupted fertility of progeny as adults. Increased NE plasma levels during pregnancy under sympathetic stress conditions correlated with decreased NET functionality that provoked changes in the development of progeny and their fertility in adulthood.

Kisspeptin is involved in ovarian follicular development during aging in rats

We have previously reported that kisspeptin (KP) may be under the control of the sympathetic innervation of the ovary. Considering that the sympathetic activity of the ovary increases with aging, it is possible that ovarian KP also increases during this period and participates in follicular development. To evaluate this possibility, we determined ovarian KP expression and its action on follicular development during reproductive aging in rats. We measured ovarian KP mRNA and protein levels in 6-, 8-, 10- and 12-month-old rats. To evaluate follicular developmental changes, intraovarian administration of KP or its antagonist, peptide 234 (P234), was performed using a mini-osmotic pump, and to evaluate FSH receptor (FSHR) changes in the senescent ovary, we stimulated cultured ovaries with KP, P234 and isoproterenol (ISO). Our results shows that KP expression in the ovary was increased in 10- and 12-month-old rats compared with 6-month-old rats, and this increase in KP was strongly correlated with the increase in ovarian norepinephrine observed with aging. The administration of KP produced an increase in corpora lutea and type III follicles in 6- and 10-month-old rats, which was reversed by P234 administration at 10 months. In addition, KP decreased the number and size of antral follicles in 6- and 10-month-old rats, while P234 administration produced an increase in these structures at the same ages. In ovarian cultures KP prevented the induction of FSHR by ISO. These results suggest that intraovarian KP negatively participates in the acquisition of FSHR, indicating a local role in the regulation of follicular development and ovulation during reproductive aging.

Noradrenaline modulates the presence of gonadotropin-releasing hormone in ovary. The importance of its interrelation on the ovarian steroidogenesis and apoptosis on dioestrus II in rat

The aim of this work was to investigate if noradrenaline (NA), added in the coeliac ganglion -superior ovarian nerve- ovary system (CG-SON-O) and in ovary incubation, modifies the release of ovarian progesterone (P4), gonadotropin-releasing hormone (GnRH) and oestradiol (E2), and the expression of 3β-HSD and 20α-HSD and proapoptotic bax and antiapoptotic bcl-2 on dioestrus II in the rat. The CG-SON-O system and the ovary were removed and placed in one cuvette containing Krebs-Ringer solution (control groups), and NA was added to the ganglion compartment in the ex vivo system and in the ovary compartment in the ovary incubation (experimental groups). P4, GnRH and E2 were measured by RIA, and gene expression was measured by RT-PCR. In the ex-vivo system, the release of ovarian P4 and GnRH and the expression of 3β-HSD and bax decreased; E2 and bcl-2 increased, and the bax/bcl-2 ratio decreased. However, in the ovary incubation, P4, GnRH, the expression of 3β-HSD and bax increased; E2, the expression of 20α-HSD and bcl-2 decreased while the bax/bcl-2 ratio increased, thus favoring apoptosis. The peripheral nervous system protected the ovary from the apoptotic mechanisms while in the ovary incubation the effect was reverted. Our results indicate that NA regulates ovarian steroidogenesis and apoptosis by modulating GnRH release from the coeliac ganglion and ovary, being NA a possible generator of a GnRH-gonadotropins axis in the ovary. This work is expected to contribute with new evidence of the clinical importance of catecholamines and GnRH in therapy and prevention of ovarian pathologies.

Reproductive hacking. A male seminal protein acts through intact reproductive pathways in female Drosophila

Seminal proteins are critical for reproductive success in all animals that have been studied. Although seminal proteins have been identified in many taxa, and female reproductive responses to receipt of these proteins have been documented in several, little is understood about the mechanisms by which seminal proteins affect female reproductive physiology. To explore this topic, we investigated how a Drosophila seminal protein, ovulin, increases ovulation rate in mated females. Ovulation is a relatively simple physiological process, with known female regulators: previous studies have shown that ovulation rate is promoted by the neuromodulator octopamine (OA) in D. melanogaster and other insects. We found that ovulin stimulates ovulation by increasing OA signaling in the female. This finding supports a model in which a male seminal protein acts through "hacking" a well-conserved, regulatory system females use to adjust reproductive output, rather than acting downstream of female mechanisms of control or in parallel pathways altogether. We also discuss similarities between 2 forms of intersexual control of behavior through chemical communication: seminal proteins and pheromones.

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.

Norepinephrine Reduces Reactive Oxygen Species (ROS) and DNA Damage in Ovarian Surface Epithelial Cells

OBJECTIVE

To determine the role of norepinephrine (NE) on DNA damage and reactive oxygen species (ROS) generation in ovarian surface epithelial cells.

METHOD

Non-tumorigenic, immortalized ovarian surface epithelial cells were treated with NE, bleomycin, and bleomycin followed by NE. The comet assay was performed on each treatment group to determine the amount of single and double-strand breaks induced by treatments. ROS levels for each treatment group were measured using the H2DCF-DA fluorescence assay. Finally, RNA transcripts were measured for each treatment group with regards to the expression of DNA repair and oxidative stress genes.

RESULTS

The mean tail moment of untreated cells was significantly greater than that of cells treated with NE (p=0.02). The mean tail moment of cells treated with bleomycin was significantly greater than that of cells treated with bleomycin followed by NE (p<0.01). Treatment with NE resulted in significantly less ROS generation than in untreated cells (p<0.01). NE treatment after hydrogen peroxide treatment resulted in a noticeable decrease in ROS generation. Genes associated with oxidative stress were upregulated in cells treated with bleomycin, however this upregulation was blunted when bleomycin-treated cells were treated subsequently with NE.

CONCLUSION

NE is associated with decreased DNA damage and ROS production in ovarian surface epithelial cells. This effect is protective in the presence of the oxidative-damaging agent bleomycin. These results suggest an additional physiologic role for the stress hormone NE, in protecting ovarian surface epithelial cells from oxidative stress.

Dopamine in human follicular fluid is associated with cellular uptake and metabolism-dependent generation of reactive oxygen species in granulosa cells: implications for physiology and pathology

STUDY QUESTION

Is the neurotransmitter dopamine (DA) in the human ovary involved in the generation of reactive oxygen species (ROS)?

SUMMARY ANSWER

Human ovarian follicular fluid contains DA, which causes the generation of ROS in cultured human granulosa cells (GCs), and alterations of DA levels in follicular fluid and DA uptake/metabolism in GCs in patients with polycystic ovary syndrome (PCOS) are linked to increased levels of ROS.

WHAT IS KNOWN ALREADY

DA is an important neurotransmitter in the brain, and the metabolism of DA results in the generation of ROS. DA was detected in human ovarian homogenates, but whether it is present in follicular fluid and plays a role in the follicle is not known.

STUDY DESIGN, SIZE AND DURATION

We used human follicular fluid from patients undergoing in vitro fertilization (IVF), GCs from patients with or without PCOS and also employed mathematical modeling to investigate the presence of DA and its effects on ROS.

PARTICIPANTS/MATERIALS, SETTING AND METHODS

DA in follicular fluid and GCs was determined by enzyme-linked immunosorbent assay. GC viability, apoptosis and generation of ROS were monitored in GCs upon addition of DA. Inhibitors of DA uptake and metabolism, an antioxidant and DA receptor agonists, were used to study cellular uptake and the mechanism of DA-induced ROS generation. Human GCs were examined for the presence and abundance of transcripts of the DA transporter (DAT; SLC6A3), the DA-metabolizing enzymes monoamine oxidases A/B (MAO-A/B) and catechol-O-methyltransferase and the vesicular monoamine transporter. A computational model was developed to describe and predict DA-induced ROS generation in human GCs.

MAIN RESULTS AND ROLE OF CHANCE

We found DA in follicular fluid of ovulatory follicles of the human ovary and in GCs. DAT and MAO-A/B, which are expressed by GCs, are prerequisites for a DA receptor-independent generation of ROS in GCs. Blockers of DAT and MAO-A/B, as well as an antioxidant, prevented the generation of ROS (P < 0.05). Agonists of DA receptors (D1 and D2) did not induce ROS. DA, in the concentration range found in follicular fluid, did not induce apoptosis of cultured GCs. Computational modeling suggested, however, that ROS levels in GCs depend on the concentrations of DA and on the cellular uptake and metabolism. In PCOS-derived follicular fluid, the levels of DA were higher (P < 0.05) in GCs, the transcript levels of DAT and MAO-A/B in GCs were 2-fold higher (P < 0.05) and the DA-induced ROS levels were found to be more than 4-fold increased (P < 0.05) compared with non-PCOS cells. Furthermore, DA at a high concentration induced apoptosis in PCOS-derived GCs.

LIMITATIONS, REASONS FOR CAUTION

While the results in IVF-derived follicular fluid and in GCs reveal for the first time the presence of DA in the human follicular compartment, functions of DA could only be studied in IVF-derived GCs, which can be viewed as a cellular model for the periovulatory follicular phase. The full functional importance of DA-induced ROS in small follicles and other compartments of the ovary, especially in PCOS samples, remains to be shown.

WIDER IMPLICATIONS OF THE FINDINGS

The results identify DA as a factor in the human ovary, which, via ROS generation, could play a role in ovarian physiology and pathology. The results obtained in samples from women with PCOS suggest the involvement of DA, acting via ROS, in this condition.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by a grant from DFG MA1080/17-3 and in part MA1080/19-1. There are no competing interests.

Drosophila seminal protein ovulin mediates ovulation through female octopamine neuronal signaling

Across animal taxa, seminal proteins are important regulators of female reproductive physiology and behavior. However, little is understood about the physiological or molecular mechanisms by which seminal proteins effect these changes. To investigate this topic, we studied the increase in Drosophila melanogaster ovulation behavior induced by mating. Ovulation requires octopamine (OA) signaling from the central nervous system to coordinate an egg's release from the ovary and its passage into the oviduct. The seminal protein ovulin increases ovulation rates after mating. We tested whether ovulin acts through OA to increase ovulation behavior. Increasing OA neuronal excitability compensated for a lack of ovulin received during mating. Moreover, we identified a mating-dependent relaxation of oviduct musculature, for which ovulin is a necessary and sufficient male contribution. We report further that oviduct muscle relaxation can be induced by activating OA neurons, requires normal metabolic production of OA, and reflects ovulin's increasing of OA neuronal signaling. Finally, we showed that as a result of ovulin exposure, there is subsequent growth of OA synaptic sites at the oviduct, demonstrating that seminal proteins can contribute to synaptic plasticity. Together, these results demonstrate that ovulin increases ovulation through OA neuronal signaling and, by extension, that seminal proteins can alter reproductive physiology by modulating known female pathways regulating reproduction.

The Noradrenergic Innervation and Steroidogenic Activity of Porcine Cystic Ovaries

The aim of the present study was to investigate the distribution and density of noradrenergic nerve fibres (NNFs), content of catecholamines (CATs) and steroids in the cystic ovaries of gilts receiving DXM from middle luteal phase. Cystic status of ovaries was induced by i.m. DXM injections on days 7-21 of the estrous cycle. During the same time, gilts in the control group received saline. The ovaries were collected on predicted day 11 of the second studied estrous cycle. The cystic ovaries were supplied by more numerous NNFs than the control gonads. Moreover after DXM injections, the content of CATs and progesterone and androstendione (A4) in the cystic wall were elevated, while the levels of A4, testosterone and estradiol-17β in the cystic fluid were lowered. Our results show that in the porcine cystic ovaries, induced by DXM injections from middle phase of estrous cycle, increased the density of NNFs and level of CATs, and that it was accompanied by changes in the content of steroids. Moreover, this study is a further confirmation that the morphological and functional changes of cystic ovaries are partly dependent on phase of the estrous cycle in which the induction of the ovarian cysts was initiated.

Expression and regulation of SNAP-25 and synaptotagmin VII in developing mouse ovarian follicles via the FSH receptor

Soluble-NSF attachment protein receptor (SNARE) proteins play a role in vesicle fusion, exocytosis, and intracellular trafficking in neuronal cells as well as in fertilization and embryogenesis. We investigated the expression patterns of two SNARE proteins, SNAP-25 and synaptotagmin VII (SytVII), and their regulation by pregnant mare serum gonadotropin (PMSG) during mouse ovarian follicular development. Ovaries were obtained at 0, 12, 24, 36, and 48 h post-PMSG injection of immature mice. SNAP-25 and SytVII mRNA expression levels increased gradually in a time-dependant manner. However, protein levels revealed different patterns of expression, suggesting different translational regulation following PMSG stimulation. SNAP-25 and SytVII expression was closely associated with thickening of the granulosa cell (GC) layer and follicle morphological changes from a flattened to a cuboidal shape. To explore follicle stimulating hormone receptor (FSHR)-mediated regulation of their expression, GCs from preantral follicles were cultured to examine the effects of FSHR siRNA knockdown. FSHR siRNA abolished upregulation of the SNAREs in both PMSG and FSH-stimulated GCs. This abolished gene expression was rescued by adding dibutyryl cyclic AMP to the cultures. These results suggest that SNAP-25 and SytVII expression is regulated via the FSHR-cAMP pathway during follicular development.

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.

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.

Sympathetic nerve activity in normal and cystic follicles from isolated bovine ovary: local effect of beta-adrenergic stimulation on steroid secretion

Cystic ovarian disease (COD) is an important cause of abnormal estrous behavior and infertility in dairy cows. COD is mainly observed in high-yielding dairy cows during the first months post-partum, a period of high stress. We have previously reported that, in lower mammals, stress induces a cystic condition similar to the polycystic ovary syndrome in humans and that stress is a definitive component in the human pathology. To know if COD in cows is also associated with high sympathetic activity, we studied isolated small antral (5 mm), preovulatory (10 mm) and cystic follicles (25 mm). Cystic follicles which present an area 600 fold greater compared with preovulatory follicles has only 10 times less concentration of NE as compared with small antral and preovulatory follicles but they had 10 times more NE in follicular fluid, suggesting a high efflux of neurotransmitter from the cyst wall. This suggestion was reinforced by the high basal release of recently taken-up 3H-NE found in cystic follicles. While lower levels of beta-adrenergic receptor were found in cystic follicles, there was a heightened response to the beta-adrenergic agonist isoproterenol and to hCG, as measured by testosterone secretion. There was however an unexpected capacity of the ovary in vitro to produce cortisol and to secrete it in response to hCG but not to isoproterenol. These data suggest that, during COD, the bovine ovary is under high sympathetic nerve activity that in addition to an increased response to hCG in cortisol secretion could participate in COD development.

Activity of Monoamine Oxidases in Rat Female Genital Organs During Preimplantation Period of Pregnancy

Our objectives in the present study were to determine the activity of monoamine oxidases A and B (MAO AB) in rat ovary, oviduct and uterus during preimplantation period of pregnancy. It should help us to clarify and better understand possible involvement of both MAO enzymes in the reproductive process. Pregnant females were killed employing a lethal dose of thiopental on the first (D1), on the third (D3), and on the fifth (D5) days of pregnancy. Rats were perfused transcardially with the PBS to rinse out of the body as much blood as possible. Ovaries, oviducts and uteri were immediately removed and stored until the measurement was done. MAO activity was determined by fluorescent monoamine oxidase detection kit. In the ovaries we have found the highest MAO activity at D3, followed by D1, and the lowest levels were recorded at D5 of pregnancy. In the oviducts, the highest MAO activity was detected again at D3, followed by D5, and by D1 of pregnancy. But statistical analysis did not reveal any difference between individual days of pregnancy nor in the ovaries, neither in uterine tubes. Uteri were the only organs, in which statistically significant differences were detected (p<0.001). The highest activity of MAO was observed at D5, followed by D1, and by D3 of pregnancy. Potential mechanisms responsible for the changed MAO activity in gonads during preimplantation period of pregnancy are proposed.

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.

Fetal and neonatal exposure to the endocrine disruptor methoxychlor causes epigenetic alterations in adult ovarian genes

Exposure to endocrine-disrupting chemicals during development could alter the epigenetic programming of the genome and result in adult-onset disease. Methoxychlor (MXC) and its metabolites possess estrogenic, antiestrogenic, and antiandrogenic activities. Previous studies showed that fetal/neonatal exposure to MXC caused adult ovarian dysfunction due to altered expression of key ovarian genes including estrogen receptor (ER)-beta, which was down-regulated, whereas ERalpha was unaffected. The objective of the current study was to evaluate changes in global and gene-specific methylation patterns in adult ovaries associated with the observed defects. Rats were exposed to MXC (20 microg/kgxd or 100 mg/kg.d) between embryonic d 19 and postnatal d 7. We performed DNA methylation analysis of the known promoters of ERalpha and ERbeta genes in postnatal d 50-60 ovaries using bisulfite sequencing and methylation-specific PCRs. Developmental exposure to MXC led to significant hypermethylation in the ERbeta promoter regions (P < 0.05), whereas the ERalpha promoter was unaffected. We assessed global DNA methylation changes using methylation-sensitive arbitrarily primed PCR and identified 10 genes that were hypermethylated in ovaries from exposed rats. To determine whether the MXC-induced methylation changes were associated with increased DNA methyltransferase (DNMT) levels, we measured the expression levels of Dnmt3a, Dnmt3b, and Dnmt3l using semiquantitative RT-PCR. Whereas Dnmt3a and Dnmt3l were unchanged, Dnmt3b expression was stimulated in ovaries of the 100 mg/kg MXC group (P < 0.05), suggesting that increased DNMT3B may cause DNA hypermethylation in the ovary. Overall, these data suggest that transient exposure to MXC during fetal and neonatal development affects adult ovarian function via altered methylation patterns.

Increases in norepinephrine release and ovarian cyst formation during ageing in the rat

BACKGROUND

Depletion of ovarian follicles is associated with the end of reproductive function in ageing females. Recently, it has been described that this process parallels increases in the concentration of norepinephrine (NE) in the rat ovary. In sexually mature rats, experimentally-induced increases in the sympathetic tone of the ovary is causally related to ovarian cyst formation and deranged follicular development. Thus, there is a possibility that increased ovarian NE concentrations represent changes in the activity of sympathetic nerves, which consequently participate in the process of ovarian cyst formation observed during ageing in the human and experimental animal models.

METHODS

Sprague-Dawley rats between 6 and 14 months old were used to analyse the capacity of the ovary to release 3H-NE recently incorporated under transmural depolarisation in relation to changes in the ovarian follicular population. Morphometric analysis of ovarian follicles and real time PCR for Bcl2 and Bax mRNA were used to assess follicular atresia.

RESULTS

From 8 months old, the induced release of recently incorporated 3H-norepinephrine (3H-NE) from the ovary and ovarian NE concentrations increased, reaching their peak values at 12 months old and remained elevated up to 14 months old. Increases in sympathetic nerve activity paralleled changes in the follicular population, as well as disappearance of the corpus luteum. In contrast, luteinised follicles, precystic follicles, and cystic follicles increased. During this period, the relationship between Bax and Bcl2 mRNAs (the proapoptotic/antiapoptotic signals) increased, suggesting atresia as the principal mechanism contributing to the decreased follicular population. When NE tone was increased, the mRNA ratio favoured Bcl2 to Bax and antiapoptotic signals dominated this period of development. Thus, these changing ratios could be responsible for the increase in luteinised follicles, as well as precystic and cystic follicles.

CONCLUSION

These data suggest that the ageing process in the ovary of the Sprague-Dawley rat is accompanied by an increased sympathetic tone of the ovary. Consequently, this sympathetic change could be related to a neuroendocrine-driven formation of a polycystic condition similar to that observed in the sympathetic-activated adult ovary.

Chronic-intermittent cold stress in rats induces selective ovarian insulin resistance

In rat ovary chronic cold stress increases sympathetic nerve activity, modifies follicular development, and initiates a polycystic condition. To see whether there is a relationship between the previously described changes in follicular development and metabolic changes similar to those in women with polycystic ovary, we have studied the effect of chronic cold stress (4 degrees C for 3 h/day, Monday to Friday, for 4 wk) on insulin sensitivity and the effect of insulin on sympathetic ovarian activity. Although cold-stressed rats ate more than the controls, they did not gain more weight. Insulin sensitivity, determined by hyperinsulinemic-euglycemic clamp, was significantly increased in the stressed animals. Insulin in vitro increased the basal release of norepinephrine from the ovaries of control rats but not from those of stressed rats, suggesting a local neural resistance to insulin in stressed rats. The levels of mRNA and protein for IRS1 and SLC2A4 (also known as GLUT4), molecules involved in insulin signaling, decreased significantly in the ovaries but not in the muscle of stressed rats. This decrease was preferentially located in theca-interstitial cells compared with granulosa cells, indicating that theca cells (the only cells directly innervated by sympathetic nerves) are responsible for the ovarian insulin resistance found in stressed rats. These findings suggest that ovarian insulin resistance produced by chronic stress could be in part responsible for the development of the polycystic condition induced by stress.