The role of intraovarian regulators in the aetiology of polycystic ovarian syndrome

1996 ◽  
Vol 5 (3) ◽  
pp. 151-168 ◽  
Author(s):  
Ghanim Almahbobi ◽  
Alan O Trounson
Keyword(s):  
Granulosa Cells ◽  
Follicular Development ◽  
Aromatase Activity ◽  
Lh Receptor ◽  
Follicular Maturation ◽  
Developmental Capacity ◽  
Follicle Selection

The present review demonstrates that the availability of bioactive FSH and LH in PCOS is normal and that granulosa cells of PCO are not apoptotic and instead hyperexpress functional FSH receptors and may possess intact aromatase activity. Consequently, these cells respond excessively to exogenous FSH stimulation and produce high amounts of oestradiol both in vivo and in vitro. The altered developmental capacity of follicles from PCO in vivo is most likely due to the abnormal follicular milieu of PCO and the culminating effects of intrafollicular inhibitors and stimulators. The failure of ovarian oestradiol production and follicular maturation to dominance in vivo may be due to a mechanism that interferes with the function of FSH, such as intraovarian steroids and growth factors. It has previously been shown that EGF and TGFα have inhibitory actions on follicular development, aromatization and LH receptor formation. In contrast, EGF enhances early follicular recruitment and growth. Therefore, it is hypothesized that EGF/TGFα may have a causal relationship in the mechanisms of anovulatory infertility in women with PCOS. Thus, an aberration in the regulation of follicular fluid EGF and/or TGFα may result in reduced numbers of granulosa cells, cessation of follicle selection and ultimately in the creation and maintenance of PCOS. The exact mechanism by which the hyperfunction of EGF/TGFα occurs and the trigger for this hyperactivity in the ovary remain to be determined. An experimental animal model may be required to assist such investigations in the future.

scholarly journals Comparative Analysis Among Different Species Reveals That the Androgen Receptor Regulates Chicken Follicle Selection Through Species-Specific Genes Related to Follicle Development

2022 ◽  
Vol 12 ◽  
Author(s):  
Ying Huang ◽  
Wei Luo ◽  
Xuliang Luo ◽  
Xiaohui Wu ◽  
Jinqiu Li ◽  
...  
Keyword(s):  
Sex Hormones ◽  
Granulosa Cells ◽  
Egg Production ◽  
Androgen Receptors ◽  
Follicular Development ◽  
Follicle Development ◽  
Follicle Selection

The differences in reproductive processes at the molecular level between viviparous and oviparous animals are evident, and the site in the ovary that synthesizes sex hormones (androgens and oestrogens) and the trends for enriching sex hormones during follicle development in chickens are different from those in mammals, suggesting that the effect of sex hormones on follicle development in chickens is probably different from that in viviparous animals. To explore the specific role of androgen receptors (ARs) on chicken follicular development, we matched the correspondence of follicular development stages among chickens, humans, cows and identified chicken-specific genes related to follicle development (GAL-SPGs) by comparing follicle development-related genes and their biological functions among species (chickens, humans, and cows). A comparison of the core transcription factor regulatory network of granulosa cells (or ovaries) based on super-enhancers among species (chicken, human, and mouse) revealed that AR is a core transcriptional regulator specific to chickens. In vivo experiments showed that inhibition of AR significantly reduced the number of syf (selected stage follicles) in chickens and decreased the expression of GAL-SPGs in F5 follicles, while in vitro experiments showed that inhibition of AR expression in chicken granulosa cells (GCs) significantly down-regulated the expression levels of GAL-SPGs, indicating that AR could regulate follicle selection through chicken-specific genes related to follicle development. A comparison among species (77 vertebrates) of the conserved genomic regions, where chicken super-enhancers are located, revealed that the chicken AR super-enhancer region is conserved in birds, suggesting that the role of AR in follicle selection maybe widespread in birds. In summary, we found that AR can regulate follicle selection through chicken-specific genes related to follicle development, which also emphasizes the important role of AR in follicle selection in chickens and provides a new perspective for understanding the unique process of follicle development in chickens. Our study will contribute to the application of androgens to the control of egg production in chickens and suggests that researchers can delve into the mechanisms of follicle development in birds based on androgen/androgen receptors.

ALTERATIONS IN GRANULOSA CELL AROMATASE ACTIVITY ACCOMPANYING PREOVULATORY FOLLICULAR DEVELOPMENT IN THE RAT OVARY WITH EVIDENCE THAT 5α-REDUCED C19 STEROIDS INHIBIT THE AROMATASE REACTION IN VITRO

1980 ◽  
Vol 84 (3) ◽  
pp. 409-419 ◽  
Author(s):  
S. G. HILLIER ◽  
AGNES M. J. VAN DEN BOOGAARD ◽  
L. E. REICHERT ◽  
E. V. VAN HALL
Keyword(s):  
Granulosa Cell ◽  
Granulosa Cells ◽  
Hormonal Regulation ◽  
Follicular Development ◽  
Biologically Active ◽  
Aromatase Activity ◽  
Adult Rat ◽  
Oestradiol Production

Locally produced androgens and oestrogens are thought to be important factors in the hormonal regulation of follicular development. In the present study the relationship between follicular maturity and granulosa cell aromatase activity has been examined in vitro. Granulosa cells harvested from the largest antral follicles in adult rat ovaries produced negligible amounts of immunoreactive oestradiol when incubated for 3 h in vitro irrespective of the day of the oestrous cycle upon which they were obtained. However, the addition of aromatizable C19 steroid substrate (testosterone, androstenedione or 19-hydroxyandrostenedione) to the incubation medium resulted in time- and concentration-dependent increases in oestradiol production which were related to the level of follicular maturity attained in vivo. By measuring oestradiol production using testosterone (10−7 mol/l) as substrate, the aromatase activity of granulosa cells obtained on the first day of vaginal dioestrus was shown to be only a fraction (less than 5%) of that observed for cells obtained on the morning of pro-oestrus. Cells obtained on the second day of dioestrus displayed an intermediate level of activity which remained approximately five times lower than that of granulosa cells at pro-oestrus. These observations, therefore, establish the induction or activation of granulosa cell aromatase activity as a correlate of normal preovulatory follicular development. However, intrafollicular androgen/oestrogen ratios may also be influenced by quantitative and/or qualitative alterations in the C19 steroidal substrate available for the aromatase reaction. Thus, the naturally occurring non-aromatizable 5α-reduced androgen metabolites, 5α-dihydrotestosterone and 5α-androstanedione, proved to be potent competitive inhibitors of the granulosa cell aromatase reaction in vitro. In this respect each of these biologically active androgens was more effective than 1-enetestololactone, an established C19 steroidal aromatase inhibitor. Since C19 steroid 5α-reductase is known to be an ovarian enzyme, it is suggested that by affecting the androgenic/oestrogenic composition of the hormonal milieu, local alterations in the activity of this enzyme may be an additional determinant of preovulatory follicular development and function.

scholarly journals Laminin-alpha6beta1 integrin interaction enhances survival and proliferation and modulates steroidogenesis of ovine granulosa cells

2002 ◽  
Vol 172 (1) ◽  
pp. 45-59 ◽  
Author(s):  
F Le Bellego ◽  
C Pisselet ◽  
C Huet ◽  
P Monget ◽  
D Monniaux
Keyword(s):  
Estrous Cycle ◽  
Granulosa Cells ◽  
Physiological Role ◽  
Follicular Development ◽  
Antral Follicles ◽  
Final Development ◽  
Beta 1 Integrin ◽  
Arginine Glycine Aspartic Acid

This study aimed to determine the physiological role of laminin (LN) and its receptor, alpha(6)beta(1) integrin, in controlling the functions of granulosa cells (GC) during follicular development in sheep ovary. Immunohistochemistry experiments showed the presence of increasing levels of LN (P<0.0001), and high levels of mature alpha(6)beta(1) integrin in GC layers of healthy antral follicles during the follicular and the preovulatory phases of the estrous cycle. In vitro, the addition of a function-blocking antibody raised against alpha(6) subunit (anti-alpha(6) IgG) to the medium of ovine GC cultured on LN impaired cell spreading (P<0.0001), decreased the proliferation rate (P<0.05) and increased the apoptosis rate (P<0.05). Furthermore, addition of anti-alpha(6) IgG enhanced estradiol (E2) secretion by GC in the presence or absence of follicle-stimulating hormone (FSH), luteinizing hormone or insulin-like growth factor-I in culture medium (P<0.0001), and inhibited progesterone (P4) secretion in basal conditions or in the presence of low (0.5 ng/ml) FSH concentrations only (P<0.0001). The anti-alpha(6) IgG effect was specific to an interaction of LN with alpha(6)beta(1) integrin since it was ineffective on GC cultured on heat-denatured LN, RGD (arginine-glycine-aspartic acid) peptides and non-coated substratum. Hence, this study established that alpha(6)beta(1) integrin 1) was expressed in GC of antral follicles, 2) mediated the actions of LN on survival, proliferation and steroidogenesis of GC, and 3) was able to dramatically modulate P4 and E2 secretion by GC in vitro. It is suggested that during the follicular and the preovulatory phases of the estrous cycle, the increasing levels of LN in GC of large antral follicles might support their final development to ovulation.

Effect of gonadotrophins on progesterone secretion by cultured granulosa cells obtained from human preovulatory follicles

1985 ◽  
Vol 110 (3) ◽  
pp. 401-407 ◽  
Author(s):  
T. Hillensjö ◽  
A. Sjögren ◽  
B. Strander ◽  
L. Nilsson ◽  
M. Wikland ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Maximal Effect ◽  
Tubal Infertility ◽  
Vitro Fertilization ◽  
Follicular Maturation ◽  
Progesterone Secretion ◽  
Preovulatory Follicles ◽  
Ultrasound Guided Puncture

Abstract. Granulosa cells were obtained from human preovulatory follicles in 31 women undergoing in vitro fertilization and embryo transfer due to tubal infertility. Follicular maturation was stimulated and synchronized by treatment with Clomiphene or human menopausal gonadotrophin (hMG), or both, plus human chorionic gonadotrophin (hCG). Follicles were aspirated by ultrasound guided puncture approximately 34–36 h after the hCG injection. The granulosa cells were washed and suspended in modified medium 199 containing 10% foetal bovine serum and cultured as monolayers for 6–8 days in the absence and presence of hormones and reactants. Progesterone formation was analyzed by RIA. In general, the cells underwent morphological luteinization and secreted high amount of progesterone. Under basal conditions the secretion of progesterone was highest during the first 2 days in culture and then gradually declined. Progesterone secretion was stimulated by human LH, hCG and the adenylate cyclase stimulator forskolin, with a maximal effect between days 2–6. The β-adrenergic agonist isoproteronol in preliminary experiments potentiated the stimulatory effect of hCG but had no own stimulatory effect. No clear differences in progesterone secretion or responsiveness to in vitro stimulation relating to the various in vivo stimulation protocols were found.

scholarly journals HIF-1α Protects Granulosa Cells From Hypoxia-Induced Apoptosis During Follicular Development by Inducing Autophagy

2021 ◽  
Vol 9 ◽  
Author(s):  
Zonghao Tang ◽  
Renfeng Xu ◽  
Zhenghong Zhang ◽  
Congjian Shi ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Mammalian Cells ◽  
Caspase 3 ◽  
Ovarian Follicle ◽  
Hypoxia Inducible Factor ◽  
Follicular Development ◽  
B Cell Lymphoma ◽  
Underlying Mechanism

Owing to the avascular structure of the ovarian follicle, proliferation of granulosa cells (GCs) and development of follicles occur under hypoxia, which is obviously different from the cell survival requirements of most mammalian cells. We hypothesized that autophagy may exert an inhibitory effect on GC apoptosis. To decipher the underlying mechanism, we constructed a rat follicular development model using pregnant mare serum gonadotropin and a cell culture experiment in hypoxic conditions (3% O2). The present results showed that the autophagy level was obviously increased and was accompanied by the concomitant elevation of hypoxia inducible factor (HIF)-1α and BNIP3 (Bcl-2/adenovirus E1B 19kDa-interacting protein 3) in GCs during follicular development. The levels of Bax (Bcl2-associated X) and Bcl-2 (B-cell lymphoma-2) were increased, while the activation of caspase-3 exhibited no obvious changes during follicular development. However, inhibition of HIF-1α attenuated the increase in Bcl-2 and promoted the increase in Bax and cleaved caspase-3. Furthermore, we observed the downregulation of BNIP3 and the decrease in autophagy after treatment with a specific HIF-1α activity inhibitor (echinomycin), indicating that HIF-1α/BNIP3 was involved in autophagy regulation in GCs in vivo. In an in vitro study, we also found that hypoxia did not obviously promote GC apoptosis, while it significantly enhanced the activation of HIF-1α/BNIP3 and the induction of autophagy. Expectedly, this effect could be reversed by 3-methyladenine (3-MA) treatment. Taken together, these findings demonstrated that hypoxia drives the activation of HIF-1α/BNIP3 signaling, which induces an increase in autophagy, protecting GC from apoptosis during follicular development.

scholarly journals Ovulatory Induction of SCG2 in Human, Nonhuman Primate, and Rodent Granulosa Cells Stimulates Ovarian Angiogenesis

Endocrinology ◽  
2018 ◽  
Vol 159 (6) ◽  
pp. 2447-2458 ◽  
Author(s):  
Patrick R Hannon ◽  
Diane M Duffy ◽  
Katherine L Rosewell ◽  
Mats Brännström ◽  
James W Akin ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Messenger Rna ◽  
Growth Factor Receptor ◽  
Endothelial Cell Migration ◽  
Receptor Signaling ◽  
Signaling Mechanism ◽  
Lh Receptor ◽  
Vitro Fertilization

Abstract The luteinizing hormone (LH) surge is essential for ovulation, but the intrafollicular factors induced by LH that mediate ovulatory processes (e.g., angiogenesis) are poorly understood, especially in women. The role of secretogranin II (SCG2) and its cleaved bioactive peptide, secretoneurin (SN), were investigated as potential mediators of ovulation by testing the hypothesis that SCG2/SN is induced in granulosa cells by human chorionic gonadotropin (hCG), via a downstream LH receptor signaling mechanism, and stimulates ovarian angiogenesis. Humans, nonhuman primates, and rodents were treated with hCG in vivo resulting in a significant increase in the messenger RNA and protein levels of SCG2 in granulosa cells collected early during the periovulatory period and just prior to ovulation (humans: 12 to 34 hours; monkeys: 12 to 36 hours; rodents: 4 to 12 hours post-hCG). This induction by hCG was recapitulated in an in vitro culture system utilizing granulosa-lutein cells from in vitro fertilization patients. Using this system, inhibition of downstream LH receptor signaling pathways revealed that the initial induction of SCG2 is regulated, in part, by epidermal growth factor receptor signaling. Further, human ovarian microvascular endothelial cells were treated with SN (1 to 100 ng/mL) and subjected to angiogenesis assays. SN significantly increased endothelial cell migration and new sprout formation, suggesting induction of ovarian angiogenesis. These results establish that SCG2 is increased in granulosa cells across species during the periovulatory period and that SN may mediate ovulatory angiogenesis in the human ovary. These findings provide insight into the regulation of human ovulation and fertility.

scholarly journals Significance of pro-angiogenic estrogen metabolites in normal follicular development and follicular growth arrest in polycystic ovary syndrome

2020 ◽  
Vol 35 (7) ◽  
pp. 1655-1665
Author(s):  
Soledad Henríquez ◽  
Paulina Kohen ◽  
Xia Xu ◽  
Claudio Villarroel ◽  
Alex Muñoz ◽  
...  
Keyword(s):  
Polycystic Ovary ◽  
Follicular Development ◽  
Male Factor Infertility ◽  
Follicular Growth ◽  
Estrogen Metabolites ◽  
Male Factor ◽  
Fertile Women

Abstract STUDY QUESTION Do alterations in pro- and anti-angiogenic estrogen metabolites in follicular fluid (FF) contribute to the follicular growth arrest and anovulation associated with polycystic ovary syndrome (PCOS)? SUMMARY ANSWER FF of PCOS women with anovulation have reduced levels of pro-angiogenic estrogen metabolites (EMs) and vascular endothelial growth factor (VEGF) compared to that of fertile women with regular menstrual cycles, but exogenous gonadotropins increase the pro-angiogenic EMs and VEGF levels in PCOS women. WHAT IS KNOWN ALREADY PCOS is characterized by the arrest of follicular development that leads to chronic anovulation. Follicular arrest is generally associated with elevated plasma levels of luteinizing hormone (LH), androgens and anti-Mullerian hormone (AMH). There is also reduced angiogenesis in the follicles of PCOS women compared to those of normal cycling women. It is known that angiogenesis is a critical factor during follicular development. We and other investigators have explored the role of EMs in ovarian angiogenesis, particularly in human corpus luteum function, showing that 4-hydroxyestrone (4-OHE1) and 16-ketoestradiol (16-kE2) have pro-angiogenic effects while 2-methoxyestradiol (2-ME2) and 2-methoxyestrone (2-ME1) have anti-angiogenic effects. Additionally, 2-hydroxyestradiol (2-OHE2), which is produced in the ovary, has proliferative and pro-angiogenic properties. We hypothesized that EMs could be involved in angiogenesis necessary for ovarian follicular development in fertile women, and that dysregulation of these factors may contribute to follicular arrest in PCOS. The relationship between EMs, VEGF and AMH in the pathophysiology of follicular arrest in PCOS has not been previously studied at a follicular level in anovulatory women without ovulation induction. STUDY DESIGN, SIZE, DURATION This is a comparative experimental study of serum and FF collected from different sized follicles (antral ˂10 mm and dominant ˃16 mm) of women with and without ovarian stimulation. The study included women with regular menstrual cycles who were proven to be fertile (n = 20) and PCOS women with follicular arrest who were candidates for ovarian drilling (n = 17), as well as other patients requiring ovarian stimulation, i.e. control women undergoing IVF for male factor infertility (n = 12) and PCOS women undergoing IVF (n = 17). In vitro studies were carried out on granulosa-lutein cells (GCs) obtained from subsets of women undergoing IVF for male factor infertility (n = 6) and PCOS women undergoing IVF (n = 6). GCs were maintained in culture for up to 6 days. PARTICIPANTS/MATERIALS, SETTING, METHODS Intrafollicular estradiol, estrone and EMs concentrations were determined by high performance liquid chromatography–mass spectrometry. Testosterone in serum was measured by RIA, and LH, FSH and sex hormone-binding globulin in serum were measured with IRMA kits. AMH was determined in serum and FF by enzyme linked immunosorbant assay (ELISA). VEGF levels were measured in FF and conditioned medium by ELISA. Conditioned medium were obtained from cultured GCs. The angiogenic potential was assessed by in vitro angiogenic assays. MAIN RESULTS AND THE ROLE OF CHANCE Pro-angiogenic EMs (4-OHE1, 16-kE2 and 2-OHE2) and VEGF were lower in FF of antral follicles of PCOS women with follicular arrest compared those of fertile women with ovulatory cycles (P &lt; 0.05). In contrast, higher concentrations of AMH were found in FF of antral follicles from PCOS women with follicular arrest compared to those of fertile women with ovulatory cycles (P &lt; 0.05). Exogenous gonadotropins used in IVF increased pro-angiogenic EMs and VEGF production in PCOS women, reaching similar profiles compared to control women receiving gonadotropins in their IVF treatment for male factor infertility. The pro-angiogenic EM 2-OHE2 increased the angiogenic potential and VEGF levels of GCs from PCOS women compared to the basal condition (P &lt; 0.05). These findings suggest that there is a role for pro-angiogenic EMs in the control of follicular VEGF production. LIMITATIONS, REASONS FOR CAUTION The limitations include the possibility that in vitro analysis of GCs might not reflect the in vivo mechanisms involved in the pro-angiogenic action of 2-OHE2 since GCs obtained at the time of oocyte retrieval belong to a very early stage of the luteal phase and might not be representative of GCs during follicular growth. Therefore, our findings do not conclusively rule out the possibility that other in vivo mechanisms also account for defective angiogenesis observed in PCOS. WIDER IMPLICATIONS OF THE FINDINGS The present study highlights the significance of EMs, angiogenic factors and AMH and their interaction in the pathophysiology of follicular development in PCOS. This study provides new insights into the role of pro-angiogenic factors in follicular arrest in PCOS. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by CONICYT/FONDECYT 1140693 and NIH grant R01HD083323. All authors declare no conflict of interest. TRIAL REGISTRATION NUMBER N/A

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

2018 ◽  
Vol 239 (1) ◽  
pp. 81-91 ◽  
Author(s):  
V Squicciarini ◽  
R Riquelme ◽  
K Wilsterman ◽  
G E Bentley ◽  
H E Lara
Keyword(s):  
Cold Stress ◽  
Polycystic Ovary ◽  
Follicular Development ◽  
Sprague Dawley ◽  
Ovarian Steroid ◽  
Sprague Dawley Rats ◽  
Mrna Expression Analysis

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.

scholarly journals An in vitro ovarian explant culture system to examine sex change in a hermaphroditic fish

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10323
Author(s):  
Alexander Goikoetxea ◽  
Erin L. Damsteegt ◽  
Erica V. Todd ◽  
Andrew McNaughton ◽  
Neil J. Gemmell ◽  
...  
Keyword(s):  
Culture System ◽  
Sex Change ◽  
Explant Culture ◽  
Culture Technique ◽  
Aromatase Activity ◽  
Histological Images ◽  
Learning Software

Many teleost fishes undergo natural sex change, and elucidating the physiological and molecular controls of this process offers unique opportunities not only to develop methods of controlling sex in aquaculture settings, but to better understand vertebrate sexual development more broadly. Induction of sex change in some sequentially hermaphroditic or gonochoristic fish can be achieved in vivo through social manipulation, inhibition of aromatase activity, or steroid treatment. However, the induction of sex change in vitro has been largely unexplored. In this study, we established an in vitro culture system for ovarian explants in serum-free medium for a model sequential hermaphrodite, the New Zealand spotty wrasse (Notolabrus celidotus). This culture technique enabled evaluating the effect of various treatments with 17β-estradiol (E2), 11-ketotestosterone (11KT) or cortisol (CORT) on spotty wrasse ovarian architecture for 21 days. A quantitative approach to measuring the degree of ovarian atresia within histological images was also developed, using pixel-based machine learning software. Ovarian atresia likely due to culture was observed across all treatments including no-hormone controls, but was minimised with treatment of at least 10 ng/mL E2. Neither 11KT nor CORT administration induced proliferation of spermatogonia (i.e., sex change) in the cultured ovaries indicating culture beyond 21 days may be needed to induce sex change in vitro. The in vitro gonadal culture and analysis systems established here enable future studies investigating the paracrine role of sex steroids, glucocorticoids and a variety of other factors during gonadal sex change in fish.

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