Comparison of Steroidogenic and Ovulation-Inducing Effects of Orthosteric and Allosteric Agonists of Luteinizing Hormone/Chorionic Gonadotropin Receptor in Immature Female Rats

Gonadotropins, including human chorionic gonadotropin (hCG), are used to induce ovulation, but they have a number of side effects, including ovarian hyperstimulation syndrome (OHSS). A possible alternative is allosteric luteinizing hormone (LH)/hCG receptor agonists, including the compound TP4/2 we developed, which remains active when administered orally. The aim was to study the effectiveness of TP4/2 (orally, 40 mg/kg) as an ovulation inducer in FSH-stimulated immature female rats, compared with hCG (s.c., 15 IU/rat). TP4/2 stimulated progesterone production and corpus luteum formation; time-dependently increased the ovarian expression of steroidogenic genes (Star, Cyp11a1, Cyp17a1) and genes involved in ovulation regulation (Adamts-1, Cox-2, Egr-1, Mt-1); and increased the content of metalloproteinase ADAMTS-1 in the ovaries. These effects were similar to those of hCG, although in some cases they were less pronounced. TP4/2, in contrast to hCG, maintained normal LH levels and increased the ovarian expression of the LH/hCG receptor gene, indicating preservation of ovarian sensitivity to LH, and did not cause a sustained increase in expression of vascular endothelial growth factor-A involved in OHSS. Thus, TP4/2 is an effective ovulation inducer that, unlike hCG, has a lower risk of OHSS and ovarian LH resistance due to its moderate stimulating effect on steroidogenesis.

Semaphorin 4C regulates ovarian steroidogenesis through RHOA/ROCK1-mediated actin cytoskeleton rearrangement

Semaphorins are a family of evolutionarily conserved morphogenetic molecules that were initially found to be associated with axonal guidance. Semaphorin 4C (Sema4C), a member of the fourth subfamily of semaphorins, has been demonstrated to play multifaceted and important roles in organ development, immune regulation, tumour growth and metastasis. However, it is completely unknown whether Sema4C is involved in the regulation of ovarian function. We found that Sema4C was widely expressed in the stroma, follicles and corpus luteum of mouse ovaries, and its expression was decreased at distinct foci in ovaries of mice of mid-to-advanced reproductive age. Inhibition of Sema4C by the ovarian intrabursal administration of recombinant adeno-associated virus (AAV)-shRNA significantly reduced oestradiol, progesterone and testosterone levels in vivo. Transcriptome sequencing analysis showed changes in pathways related to ovarian steroidogenesis and the actin cytoskeleton. Similarly, knockdown of Sema4C by siRNA interference in mouse primary ovarian granulosa cells (GCs) or thecal interstitial cells (TICs) significantly suppressed ovarian steroidogenesis and led to actin cytoskeleton disorganization. Importantly, the cytoskeleton-related pathway RHOA/ROCK1 was simultaneously inhibited after downregulation of Sema4C. Furthermore, treatment with a ROCK1 agonist after siRNA interference stabilized the actin cytoskeleton and reversed the inhibitory effect on steroid hormones described above. In conclusion, Sema4C may play an important role in ovarian steroidogenesis through regulation of the actin cytoskeleton via the RHOA/ROCK1 signalling pathway. These findings shed new light on the identification of dominant factors involved in the endocrine physiology of female reproduction.

Stimulation of Ovulation in Immature Female Rats Using Orthosteric and Allosteric Luteinizing Hormone Receptor Agonists

Human chorionic gonadotropin (hCG) and luteinizing hormone (LH) are widely used for the treatment of reproductive disorders and for controlled ovulation induction, but their use is limited by side effects. Allosteric agonists of the LH/hCG receptor, including thieno[2,3-d]thienopyrimidine TP03 developed by us, can become an alternative. TP03 (50 mg/rat, i.p.) when administered to immature female rats treated 48 h before with Follimag has been shown to increase progesterone levels (maximum 8 h post-treatment) and induce ovulation, as indicated by the appearance at 24 h corpus luteum (8.6 ± 0.5 per ovary). In terms of its activity, TP03 is comparable to hCG, although it acts more moderately. In the ovaries, unlike hCG, TP03 does not lead to an increase in the expression of vascular endothelial growth factor, which can cause ovarian hyperstimulation syndrome. Thus, TP03 is a promising drug as an ovulation inducer and ovarian steroidogenesis stimulator.

An Ovarian Steroid Metabolomic Pathway Analysis in Basal and Polycystic Ovary Syndrome (PCOS)-like Gonadotropin Conditions Reveals a Hyperandrogenic Phenotype Measured by Mass Spectrometry

Prior work has demonstrated that murine ovarian explants and isolated ovarian follicles can recapitulate human-like 28-day cycles in vitro with normal patterns of estradiol and progesterone secretion in response to gonadotropin stimulation. The objective of this study was to manipulate the gonadotropin stimulation protocol to mimic polycystic ovary syndrome (PCOS) and assess the resulting changes in ovarian steroidogenesis. A secondary aim of the study was to develop a high-throughput, sensitive, and specific liquid chromatography with tandem mass spectrometry (LC-MS/MS) assay to measure seven steroid hormones (estrone, estradiol, progesterone, testosterone, androstenedione, dehydroepiandrosterone, and dihydrotestosterone) in conditioned culture media. Ovaries were harvested from 12-day-old CD-1 mice and cultured for 28 days, with ovulation induction on culture day 14. Media were supplemented human chorionic gonadotropin (hCG, a luteinizing hormone analog) and follicle stimulating hormone (FSH) at ratios of 1:0 (standard media), 1:1 (physiologic ratio), and 3:1 (PCOS-like ratio). Ovaries cultured in PCOS-like media displayed hyperandrogenism and impaired ovulation, two key features of a PCOS-like phenotype. Taken together, this first-of-its-kind presentation of hormone levels from single tissues creates a map of the enzymatic steps most acutely affected by gonadotropin dysregulation and may provide opportunities for assessing other potential insults in PCOS pathogenesis.

Chronic overload of concentration-dependent iron exerts different effects on ovarian function in C57BL/6J mice†

Overloaded iron can deposit in the reproductive system and impair ovarian function. But few studies have identified the exact effect of overloaded iron on the endocrine function and fertility capacity in female mice. Here, we established iron-overloaded mouse models by intraperitoneal injection of iron dextran to adult female C57BL/6J mice at 0.1 g/kg (LF group), 0.5 g/kg (MF group), and 1.0 g/kg (HF group) concentrations once a week for eight consecutive weeks. We found that overloaded iron resulted in smaller ovaries, as well as accumulated oxidative damages. The endocrine function and follicle development were also impeded in the MF and HF groups. The 10-month breeding trial indicated that (1) Low concentration of iron (0.1 g/kg) wasn't detrimental to the ovary; (2) Middle concentration of iron (0.5 g/kg) impeded the childbearing process, though it could be recovered following the iron excretion; and (3) High concentration of iron (1.0 g/kg) damaged the fertility, even gave rise to sterility. Yet for those fertile mice, litter number and litter size were smaller and the ovarian reserve of their offspring was impaired. Transcriptome profiling results indicated that overloaded iron could compromise ovarian function by disrupting ovarian steroidogenesis, interfering with ovarian microenvironment, and inhibiting Wnt signaling. Taken together, we have demonstrated the effect that chronic concentration-dependent iron overload exerted on mouse ovarian function, which may act as a preliminary basis for further mechanism and intervention investigations.

Involvement of proinflammatory cytokines and metallothionein in the repairing of arsenic-mediated uterine tissue damage by curcumin

Background Curcumin is extensively used as a therapeutic intervention for treating several ailments. The antioxidant curcumin has an anti-inflammatory and chelating property with arsenic to exhibit a strong therapeutic effect on reproductive organs. This study was undertaken to describe the protective effect of noninvasive administration of curcumin against sodium-arsenite-mediated uterine hazards in female Wistar rats. Methods Twenty-four female Wistar rats were randomly divided into four groups. The treatment was continued for 8 days and given orally sodium arsenite (10 mg/kg body weight) in combination with curcumin (20 mg/kg body weight). Results Our evaluation revealed that 8 days of sodium arsenite (10 mg/kg body weight) treatment reduced the activities of the uterine enzymatic antioxidants superoxide dismutase, catalase, and peroxidase. Blood levels of vitamin B12 and folic acid decreased followed by an increased serum lactate dehydrogenase, homocysteine level, and hepatic metallothionein-1 in arsenic-treated rats. Necrosis of uterine tissue along with the disruption of ovarian steroidogenesis was marked in arsenic-treated rats with an upregulation of uterine NF-κB and IL-6 along with a raised level of serum TNF-α. Oral administration of curcumin (20 mg/kg body weight/day) in arsenic-treated rats significantly reinstated these alterations of the antioxidant system followed by an improvement of ovarian steroidogenesis and the circulating level of B12 and folate along with the downregulation of serum homocysteine, metallothionein-1, and cytokines. Conclusions The findings of this study clearly and strongly elucidated that arsenic-induced oxidative stress in uterus is linked to an alteration of inflammation-signaling biomarkers and these have been protected through the co-administration of curcumin due to its anti-inflammatory, free radical scavenging, and antioxidant activity by the possible regulation of an S-adenosine methionine pool.

Genome-wide interactions between FSH and insulin-like growth factors in the regulation of human granulosa cell differentiation

Study question

Is the genome-wide response of human cumulus cells to FSH and insulin-like growth factors (IGFs) comparable to the response observed in undifferentiated granulosa cells (GCs)?

Summary answer

FSH actions in human cumulus cells mimic those observed in preantral undifferentiated GCs from laboratory animals, and approximately half of the regulated genes are dependent on the simultaneous activation of the IGF1 receptor (IGF1R).

What is known already

Animal studies have shown that FSH and the IGFs system are required for follicle growth and maturation. In humans, IGF levels in the follicular fluid correlate with patients' responses to IVF protocols. The main targets of FSH and IGFs in the ovary are the GCs; however, the genomic mechanisms involved in the response of GCs to these hormones are unknown.

Study design, size, duration

Human cumulus cells isolated from IVF patients were cultured for 48 h in serum-free media in the presence of vehicle, FSH, IGF1R inhibitor or their combination.

Participants/materials, setting, methods

Discarded cumulus cells were donated to research by reproductive-aged women undergoing IVF due to non-ovarian etiologies of infertility at a university-affiliated clinic. The effect of FSH and/or IGF1R inhibition on cumulus cell function was evaluated using Affymetrix microarrays, quantitative PCR, western blot, promoter assays and hormone level measurements.

Main results and the role of chance

The findings demonstrate that human cumulus cells from IVF patients respond to FSH with the expression of genes known to be markers of the preantral to preovulatory differentiation of GCs. These results also demonstrate that ~50% of FSH-regulated genes require IGF1R activity and suggest that several aspects of follicle growth are coordinately regulated by FSH and IGFs in humans. This novel approach will allow for future mechanistic and molecular studies on the regulation of human follicle maturation.

Large scale data

Data set can be accessed at Gene Expression Omnibus number GSE86427.

Limitations, reasons for caution

Experiments were performed using primary human cumulus cells. This may not represent the response of intact follicles.

Wider implications of the findings

Understanding the mechanisms involved in the regulation of GC differentiation by FSH and IGF in humans will contribute to improving treatments for infertility.

Study funding/competing interest(s)

The project was financed by the National Instituted of Health grant number R56HD086054 and R01HD057110 (C.S.). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. We have no competing interests to declare.

Selective inhibition of steroidogenic enzymes by ketoconazole in rat ovary cells

OBJECTIVE

Ketoconazole (KCZ) is an anti-fungal agent extensively used for clinical applications related to its inhibitory effects on adrenal and testicular steroidogenesis. Much less information is available on the effects of KCZ on synthesis of steroid hormones in the ovary. The present study aimed to characterize the in situ effects of KCZ on steroidogenic enzymes in primary rat ovary cells.

METHODS

Following the induction of folliculogenesis in gonadotropin treated rats, freshly prepared ovarian cells were incubated in suspension for up to four hours while radiolabeled steroid substrates were added and time dependent generation of their metabolic products was analyzed by thin layer chromatography (TLC).

RESULTS

KCZ inhibits the P450 steroidogenic enzymes in a selective and dose dependent manner, including cholesterol side-chain cleavage cytochrome P450 (CYP11A1/P450scc), the 17α-hydroxylase activity of CYP17A1/P450c17, and CYP19A1/P450arom, with IC₅₀ values of 0.3, 1.8, and 0.3 μg/mL (0.56, 3.36, and 0.56 μM), respectively. Unaffected by KCZ, at 10 μg/mL, were the 17,20 lyase activity of CYP17A1, as well as five non-cytochrome steroidogenic enzymes including 3β-hydroxysteroid dehydrogenase-Δ^5–4 isomerase type 1 (3βHSD1), 5α-reductase, 20α-hydroxysteroid dehydrogenase (20α-HSD), 3α-hydroxysteroid dehydrogenase (3α-HSD), and 17β-hydroxysteroid dehydrogenase type 1 (17HSD1).

CONCLUSION

These findings map the effects of KCZ on the ovarian pathways of progestin, androgen, and estrogen synthesis. Hence, the drug may have a potential use as an acute and reversible modulator of ovarian steroidogenesis in pathological circumstances.

Cryopreservation time does not decrease follicular viability in ovarian tissue frozen for fertility preservation

OBJECTIVE

To determine the effect of storage duration on cryopreserved ovarian tissue using fresh and frozen-thawed samples.

METHODS

Seventeen fertile patients underwent an ovarian biopsy during elective laparoscopic tubal ligation. The tissue sample was divided into three parts: one part was processed fresh (FG), and two were slowly frozen, cryopreserved for 30 (G30) or 180 days (G180), thawed and analyzed. Follicular density, follicular viability, and steroidogenic capacity were assessed.

RESULTS

We observed no differences between the groups in follicular density, which was assessed in hematoxylin and eosin-stained tissue sections. A heterogeneous follicular distribution was observed in the parenchyma, with a mean density of 361.3±255.4, 454.9±676.3, and 296.8±269.0 follicles/mm(3) for FG, G30 and G180, respectively (p = 0.46). Follicular viability was greater in FG (93.4%) when compared with the cryopreserved tissues (70.8% for G30 (p<0.001) and 78.4% for G180 (p<0.001)), with no difference in viability between the frozen samples (p>0.05). The steroidogenic capacity of the tissue was not significantly reduced following cryopreservation.

CONCLUSION

The slow freezing procedures used for ovarian cryopreservation are capable of preserving follicular viability and maintaining the steroidogenic capacity of the tissue despite a roughly 30% decrease in follicular viability. Furthermore, short-term storage of ovarian tissue does not appear to compromise follicle integrity.