Steroidogenesis In Granulosa Cells Research Articles

Moxibustion ameliorates ovarian function in premature ovarian insufficiency rats by activating cAMP/PKA/CREB to promote steroidogenesis in ovarian granulosa cells

Moxibustion ameliorates ovarian function in premature ovarian insufficiency rats by activating cAMP/PKA/CREB to promote steroidogenesis in ovarian granulosa cells

The influence of indole propionic acid on molecular markers of steroidogenesis, ER stress, and apoptosis in rat granulosa cells exposed to high glucose conditions

Hyperglycemia is known as one of the main causes of infertility in human societies. Indole propionic acid (IPA) is produced by intestinal microbiota and has antioxidant and anti-inflammatory properties. This study aims to investigate the effects of IPA on molecular indices of steroidogenesis, ER stress, and apoptosis induced by high glucose (HG) in granulosa cells. Primary GCs, isolated from ovarian follicles of Rats were cultured in 5 mM (control) and 30 mM (HG) of glucose and in the presence of 10 and 20 µM of IPA for 24 h. The cell viability was assessed by MTT. The gene expression of P450SCC, 3βHSD, CYP19A, BAX, BCL2, and STAR was evaluated by Real-Time PCR. Protein expression of ATF6, PERK, GRP78, and CHOP determined by western blot. Progesterone, estradiol, IL-1β, and TNF-α were measured by ELISA. HG decreased the viability, and expression of P450SCC, 3βHSD, CYP19A, BCL2, STAR, and increased BAX. 10 and 20 µM of IPA increased cell viability, expression of P450SCC, 3βHSD, CYP19A, BCL2 and STAR and decreased BAX compared to the HG group. The expression of ATF6, PERK, GRP78, and CHOP proteins increased by HG and IPA decreased the expression of these proteins compared to the HG group. Also, HG decreased progesterone and estradiol levels and increased IL-1β and TNF-α. IPA significantly increased progesterone and estradiol and decreased IL-1β and TNF-α compared to the HG group. IPA can improve the side effects of HG in GCs of rats, as responsible cells for fertility, by improving steroidogenesis, regulation of ER-stress pathway, suppression of inflammation, and apoptosis.

Exosomal or follicular FNDC3A decreases FOLR1 mRNA abundance and progesterone and lactate synthesis in bovine granulosa cells.

Dairy cattle experience a period of infertility postpartum that is caused in part by the development of IGF1/insulin resistance. This study suggests that an adipokine, FNDC3A, reduces IGF1-dependent glycolysis and may contribute to postpartum infertility. Dairy cows go through a period of subfertility after parturition, triggered in part by a disruption of energy homeostasis. The mobilization of body fat alters the secretion of adipokines, which have been shown to impact ovarian function. Fibronectin type III domain-containing 3A (FNDC3A) is a recently discovered adipokine-myokine, and FNDC3A mRNA abundance in subcutaneous adipose tissue is increased postpartum in cattle. In this study, we hypothesized that FNDC3A may compromise granulosa cell function in cattle and investigated this using a well-established in vitro cell culture model. Here, we demonstrate the presence of FNDC3A protein associated with extracellular vesicles in follicular fluid and in plasma, suggesting an endocrine role for this adipokine. FNDC3A protein and mRNA was also detected in the bovine ovary (cortex, granulosa and theca cells, cumulus, oocyte and corpus luteum). Abundance of FNDC3A mRNA in granulosa cells from small follicles was increased by in vitro treatment with the adipokines leptin and TNF but not by visfatin, resistin, adiponectin, chemerin or IGF1. Addition of recombinant FNDC3A at physiological doses (10 ng/mL) to granulosa cells decreased IGF1-dependent progesterone but not estradiol secretion and IGF1-dependent lactate secretion and abundance of GLUT3 and GLUT4 mRNA. This concentration of FNDC3A increased cell viability, abundance of mRNA encoding a putative receptor FOLR1, and increased phosphorylation of Akt. Collectively, these data suggest that FNDC3A may regulate folliculogenesis in cattle by modulating IGF1-dependent granulosa cell steroidogenesis and glucose metabolism.

Resveratrol Promotes Proliferation, Antioxidant Properties, and Progesterone Production in Yak (Bos grunniens) Granulosa Cells.

Resveratrol (RES) is a class of natural polyphenolic compounds known for its strong anti-apoptotic and antioxidant properties. Granulosa cells (GCs) are one of the important components of ovarian follicles and play crucial roles in follicular development of follicles in the ovary. Here, we explored the effects of RES on the proliferation and functions of yak GCs. Firstly, we evaluated the effect of RES dose and time in culture on the viability of GCs, and then the optimum treatment protocol (10 μM RES, 36 h) was selected to analyze the effects of RES on the proliferation, cell cycle, apoptosis, malondialdehyde (MDA), glutathione (GSH), reactive oxygen species (ROS) accumulation, lipid droplet content, ATP production, and steroidogenesis of GCs, as well as the expression of related genes. The results show that RES treatment significantly (1) increased cell viability and proliferation and inhibited cell apoptosis by upregulating BCL-2 and SIRT1 genes and downregulating BAX, CASP3, P53, and KU70 genes; (2) increased the proportion of GCs in the S phase and upregulated CCND1, PCNA, CDK4, and CDK5 genes; (3) reduced ROS accumulation and MDA content and increased GSH content, as well as upregulating the relative expression levels of CAT, SOD2, and GPX1 genes; (4) decreased lipid droplet content and increased ATP production; (5) promoted progesterone (P4) secretion and the expression of P4 synthesis-related genes (StAR, HSD3B1, and CYP11A1); and (6) inhibited E2 secretion and CYP19A1 expression. These findings suggest that RES at 10 μM increases the proliferation and antioxidant properties, inhibits apoptosis, and promotes ATP production, lipid droplet consumption, and P4 secretion of yak GCs.

Lipopolysaccharide-binding protein in follicular fluid is associated with the follicular inflammatory status and granulosa cell steroidogenesis in dairy cows.

Metabolic stress and subsequent hepatic dysfunction in high-producing dairy cows are associated with inflammatory diseases and declining fertility. Lipopolysaccharide (LPS)-binding protein (LBP) is produced by hepatocytes and controls the immune response, suggesting that it is involved in the pathophysiology of inflammation-related attenuation of reproductive functions during metabolic stress. This study investigated the effect of LBP on the inflammatory status, oocyte quality, and steroidogenesis in the follicular microenvironment of dairy cows. Using bovine ovaries obtained from a slaughterhouse, follicular fluid and granulosa cells were collected from large follicles to evaluate the follicular status of metabolism, inflammation, and steroidogenesis. Cumulus-oocyte complexes were aspirated from small follicles and subjected to in vitro embryo production. The results showed that follicular fluid LBP concentrations were significantly higher in cows with fatty livers and hepatitis than in those with healthy livers. Follicular fluid LBP and LPS concentrations were negatively correlated, whereas LPS concentration showed a positive correlation with the concentrations of non-esterified fatty acids (NEFA) and β-hydroxybutyric acid in follicular fluid. The blastulation rate of oocytes after in vitro fertilization was impaired in cows in which coexisting large follicles had high NEFA levels. Follicular fluid NEFA concentration was negatively correlated with granulosa cell expression of the estradiol (E2) synthesis-related gene (CYP19A1). Follicular fluid LBP concentration was positively correlated with follicular fluid E2 concentration and granulosa cell CYP19A1 expression. In conclusion, follicular fluid LBP may be associated with favorable conditions in the follicular microenvironment, including low LPS levels and high E2 production by granulosa cells.

Resveratrol protects against high glucose-induced steroidogenesis and apoptosis in murine granulosa cells

Resveratrol protects against high glucose-induced steroidogenesis and apoptosis in murine granulosa cells

PSIV-4 Impact of Lipopolysaccharide Endotoxin on Growth and Viability of Ovarian Granulosa Cells

Abstract Lipopolysaccharide (LPS) endotoxin from Gram-negative bacteria has been demonstrated to negatively impact reproductive parameters leading to ovarian dysfunction. Ovarian granulosa cells express the toll-like receptor 4 complex necessary to elicit inflammatory immune responses in the presence of LPS. Quantifiable amounts of LPS have been detected in follicular fluid from slaughterhouse-derived ovaries with further deleterious effects on granulosa cell steroidogenesis. Therefore, the objective of this study was to investigate the effects of LPS on granulosa cell proliferation in vitro. We hypothesized that increasing concentrations of LPS would negatively impact granulosa cell proliferation dynamics. A human granulosa cell line (KGN) was plated at 60% confluency in 96-well tissue culture plates and treated with phosphate buffered saline-vehicle or LPS (0.01, 0.1, 1, or 10 µg/mL) in the presence or absence of follicle-stimulating hormone (FSH). Cells were incubated for 48 h at 37 ºC and 5% CO2 in an IncuCyte incubator that utilizes real-time automated microscopy to continuously capture images of cells and measure cell confluency. Individual well images were collected every 6 h. The study was performed in 3 independent experiments with 8 replicates per treatment group in each experiment. Cells were allowed to equilibrate in the IncuCyte for 6 h before image collection. Cell confluency for each treatment group was normalized to vehicle-treated control confluency at 6 h. A significant difference was observed at the initial 6 h timepoint, with 1 and 10 µg/mL LPS treatment groups demonstrating decreased cell confluency compared with vehicle-treated controls (P < 0.05). However, no significant difference was observed in 0.01 (P = 0.65) and 0.1 (P = 0.53) µg/mL LPS treatment groups compared with vehicle-treated controls at 6 h timepoint. Interestingly, the deleterious effects of LPS on confluency and cell growth parameters were mitigated with the addition of FSH. No observable differences were detected in the two largest LPS doses concurrently incubated with FSH, 1 and 10 µg/mL LPS (P = 0.55 and P = 0.62, respectively), compared with vehicle-treated controls. From 12 h until the end of the incubation period, cell confluency in 1 and 10 µg/mL LPS treatment groups remained significantly different compared with FSH-treated cells (P < 0.05). Comparably, no differences were detected among FSH-stimulated groups, regardless of LPS dose or time (P = 0.99). Results indicate that greater LPS concentrations (1 and 10 µg/mL) negatively impacts cell confluency and proliferation in vitro; however, FSH has the ability to protect granulosa cells against the detrimental effects that LPS has on cell confluency. These data suggest that FSH is critical in regulating cell growth and proliferation despite the action of inflammatory pathways induced by bacterial endotoxin.

PSV-4 Effects of Asprosin on Nuclear Sirtuins Expression in Bovine Granulosa Cells

Abstract Asprosin is an adipokine that regulates steroid production in granulosa cells (GC). Sirtuins are a family of NAD+-dependent deacetylases associated with GC function. In the nucleus, sirtuins are epigenetic regulators of gene expression. Although the literature shows that sirtuins and asprosin affect GC steroidogenesis and proliferation, studies are required to investigate whether their actions are linked. The aims of this study are to determine the influence of asprosin on mRNA expression of nuclear sirtuins and their association with steroidogenic regulators in bovine GC. GC were isolated from small antral follicles (1 to 5mm) of bovine ovaries, cultured in vitro, and treated with or without asprosin (200 ng/mL) in combination with FSH (30 ng/mL) or IGF1 (30 ng/mL). Cells were cultured for 24 h and submitted to RNA extraction (n = 5 pools). Relative mRNA abundance of SIRTs 1, 2, 6, 7, aromatase (CYP19A1), IGF1 receptor (IGF1r), and FSH receptor (FSHr) were determined via RT-qPCR using 18S as a housekeeping gene. Data were analyzed via factorial ANOVA with GLM procedures of SAS for Windows (SAS Institute Inc., Cary, NC). Normality was tested using the Shapiro-Wilk test. Data sets that showed non-gaussian distribution (P >0.05) after log-transformation were analyzed via the Kruskal-Wallis test followed by Dunn’s post hoc test using GraphPad Prism 9.2.0. Differences among treatments were considered significant at P < 0.05, and a tendency at 0.05< P < 0.10. Pearson correlation was performed using PROC CORR procedures of SAS for Windows (version 9.4, SAS Institute Inc., Cary, NC). SIRT1 (P < 0.05) mRNA abundance increased after Asprosin treatment in comparison with FSH alone and in combination with asprosin as well as to IGF1 alone. Also, SIRT1 under asprosin treatment showed a tendency (P < 0.06) to be increased in comparison with negative control. Additionally, a very high correlation (r = 0.999; P < 0.05) between CYP19A1 and SIRT1 was observed in the treatment with asprosin. SIRT2 had a tendency (P < 0.08) to increase after treatment with asprosin in comparison with FSH alone. Moreover, SIRT2 has a very high (r = 0.995; P < 0.005) correlation to CYP19A1 after treatment of FSH in combination with asprosin and a significant (r = 0.676; P < 0.05) correlation with IGF1r. Asprosin treatment led to a very high (r = 0.997; P < 0.05) correlation of SIRT6 with FSHr. Also, when asprosin was combined with FSH, a very high (r = 0.993, P < 0.01) correlation between SIRT6 and CYP19A1 was observed. SIRT7 mRNA relative abundance decreased (P < 0.05) after treatment with IGF1 in comparison to the negative control. No significant correlation was observed between SIRT7 and CYP19A1 or receptors. In summary, asprosin increases expression of SIRT1 and increases the correlation between SIRTs 1, 2, 6, and aromatase. These results indicate that the actions of asprosin on steroidogenesis involve sirtuins regulation.

High expression of miR-22-3p in chicken hierarchical follicles promotes granulosa cell proliferation, steroidogenesis, and lipid metabolism via PTEN/PI3K/Akt/mTOR signaling pathway

MicroRNAs (miRNAs) are a class of RNA macromolecules that play regulatory roles in follicle development by inhibiting protein translation through binding to the 3’UTR of its target genes. Granulosa cell (GC) proliferation, steroidogenesis, and lipid metabolism have indispensable effect during folliculogenesis. In this study, we found that miR-22-3p was highly expressed in the hierarchical follicles of the chickens, which indicated that it may be involved in follicle development. The results obtained suggested that miR-22-3p promoted proliferation, hormone secretion (progesterone and estrogen), and the content of lipid droplets (LDs) in the chicken primary GC. The results from the bioinformatics analysis, luciferase reporter assay, qRT-PCR, and Western blotting, confirmed that PTEN was directly targeted to miR-22-3p. Subsequently, it was revealed that PTEN inhibited proliferation, hormone secretion, and the content of LDs in GC. Therefore, this study showed that miR-22-3p could activate PI3K/Akt/mTOR pathway via targeting PTEN. Taken together, the findings from this study indicated that miR-22-3p was highly expressed in the hierarchical follicles of chickens, which promotes GC proliferation, steroidogenesis, and lipid metabolism by repressing PTEN to activate PI3K/AKT/mTOR pathway.

In vitro exposure to triazoles used as fungicides impairs human granulosa cells steroidogenesis

Triazoles are the main components of fungicides used in conventional agriculture. Some data suggests that they may be endocrine disruptors. Here, we found five triazoles, prothioconazole, metconazole, difenoconazole, tetraconazole, and cyproconazole, in soil or water from the Centre-Val de Loire region of France. We then studied their effects from 0.001 µM to 1000 µM for 48 h on the steroidogenesis and cytotoxicity of ovarian cells from patients in this region and the human granulosa line KGN. In addition, the expression of the aryl hydrocarbon receptor (AHR) nuclear receptor in KGN cells was studied. Overall, all triazoles reduced the secretion of progesterone, estradiol, or both at doses that were non-cytotoxic but higher than those found in the environment. This was mainly associated, depending on the triazole, with a decrease in the expression of CYP51, STAR, CYP11A1, CYP19A1, or HSD3B proteins, or a combination thereof, in hGCs and KGN cells and an increase in AHR in KGN cells.

Perfluorooctanoic acid (PFOA) inhibits steroidogenesis and mitochondrial function in bovine granulosa cells in vitro

Perfluorooctanoic acid (PFOA) is a persistent environmental contaminant. Due to the ubiquitous presence of PFOA in the environment, the impacts of PFOA exposure not only affect human reproductive health but may also affect livestock reproductive health. The focus of this study was to determine the effects of PFOA on the physiological functions of bovine granulosa cells in vitro. Primary bovine granulosa cells were exposed to 0, 4, and 40 μM PFOA for 48 and 96 h followed by analysis of granulosa cell function including cell viability, steroidogenesis, and mitochondrial activity. Results revealed that PFOA inhibited steroid hormone secretion and altered the expression of key enzymes required for steroidogenesis. Gene expression analysis revealed decreases in mRNA transcripts for CYP11A1, HSD3B, and CYP19A1 and an increase in STAR expression after PFOA exposure. Similarly, PFOA decreased levels of CYP11A1 and CYP19A1 protein. PFOA did not impact live cell number, alter the cell cycle, or induce apoptosis, although it reduced metabolic activity, indicative of mitochondrial dysfunction. We observed that PFOA treatment caused a loss of mitochondrial membrane potential and increases in PINK protein expression, suggestive of mitophagy and mitochondrial damage. Further analysis revealed that these changes were associated with increased levels of reactive oxygen species. Expression of autophagy related proteins phosphoULK1 and LAMP2 were increased after PFOA exposure, in addition to an increased abundance of lysosomes, characteristic of increased autophagy. Taken together, these findings suggest that PFOA can negatively impact granulosa cell steroidogenesis via mitochondrial dysfunction.

FRI392 Functional Interrelationship Between Oxytocin And Bone Morphogenetic Proteins In Ovarian Steroidogenesis By Granulosa Cells

Abstract Disclosure: K. Yamamoto: None. Y. Nakano: None. N. Iwata: None. Y. Soejima: None. A. Suyama: None. T. Hasegawa: None. F. Otsuka: None. Oxytocin (OXT) is a neuropeptide that is produced in the hypothalamus and is secreted from the posterior pituitary. OXT has diverse physiological roles mediated by the OXT receptor (OXTR), including not only stimulation of uterine contractions during labor and peripheral functions of milk ejection during lactation but also functions in pair bonding, maternal nurturing, and social behavior related to the action of OXT on the brain. It has been shown that OXT and OXTR are expressed in ovarian granulosa cells (GCs) in several species including humans. Secretion of OXT by bovine GCs is reported to be increased after the preovulatory luteinizing hormone surge, which is coincident with an increase in progesterone secretion and a decrease in secretion of estradiol and androgen, suggesting a functional interrelationship between OXT and ovarian steroidogenesis. It has been demonstrated that application of OXT to cultures of GCs from preovulatory follicles in bovines, marmoset monkeys, and humans led to increases in progesterone production. However, the precise molecular mechanism by which OXT modulates ovarian steroidogenesis in GCs remains unknown. Bone morphogenetic proteins (BMPs), which belong to the transforming growth factor beta (TGF-β) superfamily, play important roles in steroidogenesis and cellular proliferation in ovarian follicles via autocrine/paracrine fashion. BMP ligands and receptors are expressed in a cell-dependent manner in the ovary and have a pivotal role in female fertility. Throughout folliculogenesis, BMPs commonly inhibit follicle-stimulating hormone (FSH)-induced progesterone production, and oocyte-derived factors BMP-6 and BMP-15 are known to act on GCs through BMP receptors and suppress FSH-induced progesterone synthesis. To clarify the reproductive role of OXT in ovarian steroidogenesis and its functional interaction with BMPs, the effects of OXT on ovarian steroidogenesis were investigated by using primary culture of rat GCs and human granulosa KGN cells. Here we found that the OXT receptor was expressed in both rat GCs and human KGN cells and that OXT treatment significantly increased FSH- and forskolin (FSK)-induced progesterone production, but not estradiol production, by rat GCs and KGN cells, respectively. In accordance with the effects of OXT on progesterone production, OXT enhanced mRNA levels of CYP11A1 and HSD3B2 induced by FSK in KGN cells. Of note, OXT enhanced the phosphorylation of SMAD1/5/9 and the mRNA level of ID1 induced by BMP-15, but not those induced by BMP-6, in KGN cells. It was also revealed that OXT application upregulated the expression of BMPR2, a crucial type-II receptor of BMP-15, and enhanced the BMP-15-induced expression of inhibitory SMAD6 by KGN cells. Taken together, it was shown that OXT enhances ovarian progesterone production with upregulation of BMP-15 activity, leading to a fine-tuning of ovarian steroidogenesis. Presentation: Friday, June 16, 2023

OR19-05 Human Induced Pluripotent Stem Cell-derived Granulosa-like Cells From Ligand-based Differentiation Express FOXL2 After Inhibition Of DKK1

Abstract Disclosure: H. Kubo: None. M.M. Laronda: None. Premature ovarian insufficiency (POI) is characterized by the loss of ovarian function prior to an individual reaching the age of 40. POI can have serious ramifications on health, reducing average life expectancy, and can develop from iatrogenic treatments or genetic variants. POI patients can receive hormone replacement therapies (HRTs), but current methods are not dynamic, responsive, or comprehensive. Contrastingly, cell-based therapies have the potential to produce hormones other than estrogen or progesterone and respond dynamically to each patient. Using human induced pluripotent stem cells (hiPSCs) to generate such cell-based therapies may mitigate rejection upon transplantation and allow for personalized therapies for POI patients. Therefore, we propose to differentiate hiPSCs into granulosa like cells (GLCs) that are functionally the same as granulosa cells (GCs), which are responsible for aromatizing androgens into estrogens. One factor critical to steroidogenesis in GCs is FOXL2, which in mice is suppressed by DKK1, a WNT inhibitor. Therefore, we hypothesized that FOXL2 expression and subsequent steroidogenic functions in our GLCs will be influenced by DKK1. To generate GLCs, we treated the cells with WNT agonist CHIR99021 for two days which has been shown to induce the intermediate mesoderm, and then BMP4 and FST for three days to induce the ovarian somatic lineage. We analyzed our cultures for self-renewal (POU5F1), intermediate mesoderm (PAX2, LHX1, WT1), coelomic epithelium (EMX2), genital ridge (GATA4, NR5A1), and GC (FOXL2) markers using qPCR to assess correct lineage commitment. At day 2, we observed approximately 4000-fold induction of PAX2, 20-fold induction of LHX1, 35-fold increase of WT1, 3000-fold induction of GATA4, and 3.5-fold induction in FOXL2 transcript expression. At day 5, we observed 10-fold induction of NR5A1. We also observed a 7000-fold increase of DKK1 at day 2. Addition of Gallocyanine, a DKK1 inhibitor, from days 2 to 5 resulted in induction of FOXL2 protein expression at day 5, captured by immunofluorescence imaging. Analysis of the images showed that Gallocyanine-treated cells were 42.4% positive for FOXL2, while cells untreated were 0.325% positive for FOXL2. This data suggests that DKK1 does suppress FOXL2 expression in these hiPSC-derived GLCs and demonstrates the potential of these cells as a model to investigate mechanisms important to GC development and maintenance. Future steps include testing the steroidogenic abilities of the GLCs and identification of culture conditions needed to maximize steroidogenesis. This work is supported by the NIH/NICHD R01HD104683 (MML), HuBMAP U01HD110336 (MML), Warren and Eloise Batts Endowment (MML), a Debicki Foundation Grant (MML), the Burroughs Wellcome Fund Career Award at the Scientific Interface (MML), Gesualdo Family Research Scholar (MML), and NIH/NCI training grant T32 CA009560 (HK). Presentation Date: Saturday, June 17, 2023

Sphingosine-1-phosphate mediates FSH-induced cell viability but not steroidogenesis in bovine granulosa cells

Follicle-stimulating hormone (FSH) stimulates the proliferation, survival, and estradiol synthesis of granulosa cells by binding to their G protein-coupled receptors. Although FSH activates sphingosine kinase-1 (SPHK1) to induce sphingosine-1-phosphate (S1P) synthesis, which is required to mediate the proliferative and survival effect of this gonadotrophin, the mechanisms, and the role of S1P in estradiol synthesis have not been reported. This study aimed to evaluate the importance of FSH-induced S1P synthesis as a mediator of the effects of this gonadotrophin on granulosa cell viability and steroidogenesis and to determine if FSH-induced S1P synthesis depends on estradiol, cAMP, PKA, or PKC. To achieve these objectives, we tested the effects of FSH, a sphingosine kinase-1 inhibitor (SKI-178), estradiol and inhibitors of aromatase, cAMP, PKA, and PKC (Formestane, MDL-12330A, H-89 dihydrochloride hydrate and Calphostin C respectively), on granulosa cell viability, S1P and estradiol production, and the mRNA expression of CYP19A1 and STAR in four in vitro culture experiments. The addition of FSH (1 ng/mL) increased (P < 0.05) granulosa cells number and S1P concentration in the culture media. Conversely, the addition of SKI-178 (10 μM) reduced (P < 0.05) S1P concentration negating the effect of FSH on cell viability. Inhibition of PKC and PKA, but not cAMP, reduced (P < 0.05) S1P secretion of FSH treated granulosa cells. It is important to note that the reduction in S1P secretion was strong (49 %) with the use of the PKC inhibitor. The use of formestane (10 μg) did not modify (P > 0.05) S1P secretion in FSH-treated cells; however, the addition of 5 or 10 ng/mL of estradiol increased (P < 0.05) S1P secretion. Finally, FSH increased (P < 0.05) estradiol concentration in the culture media, but this effect was not blocked by the inhibition of S1P synthesis. Similarly, FSH, SKI-178 or their combination did not modify the mRNA expression of CYP19A1 and STAR. In conclusion, S1P synthesis is stimulated FSH in granulosa cells and mediated mainly by PKC. S1P in turn promotes the granulosa cell viability, however, this does not influence estradiol synthesis. Additionally, estradiol synthesis induced by FSH is not essential for S1P synthesis, however high estradiol concentration may stimulate S1P production by granulosa cells.

FRI376 Regulation Of Theca Cell Function By Salt-Inducible Kinases

Abstract Disclosure: M. Rodriguez Esquivel: None. E. Hayes: None. O. Lakomy: None. M. Hassan: None. R. Filzen: None. C.O. Stocco: Grant Recipient; Self; NIH R01HD097202. The most common identifiable factors of female infertility are ovulatory disorders. Ovulation is the pinnacle of folliculogenesis, a process that requires an interplay between the oocyte, the granulosa cells, and the theca cells (TCs). TCs are the only source of ovarian androgens. Androgens play vital roles in female fertility acting as substrates for estrogen production in granulosa cells and directly regulating ovarian function via the activation of the androgen receptor. However, abnormally elevated androgen levels reduce fertility in humans and animals, suggesting that a delicate equilibrium exists between the beneficial and harmful effects of androgens in the ovary. Therefore, uncovering novel mechanisms regulating androgen synthesis in TCs is of great significance. The capacity of TCs to synthesize androgens relies on the expression of the rate-limiting enzyme CYP17A1, which converts progestogens into androgens, and its stimulation by the luteinizing hormone (LH). Previously, our group showed that salt-inducible kinases (SIKs) regulate granulosa cell steroidogenesis. Here, we investigated whether SIKs play any role in the regulation of androgen production in TCs. SIK2 and SIK3 were detected by IHC in the TCs of rat ovaries. Western blot confirmed this finding using isolated rat TCs. Next, rat TCs in culture were treated with LH in the presence or absence of HG, a highly specific SIK inhibitor. SIK inhibition enhanced the stimulatory effect of LH on Cyp17a1 mRNA expression. HG alone also increased Cyp17a1 expression to levels higher than those found in the presence of LH. Similarly, HG alone increased testosterone and potentiated LH stimulation of testosterone production. SIK inhibition also enhanced the stimulatory effect of LH on the expression of StAR and Cyp11a1. Concentration-response experiments for the SIK inhibitor in the presence or absence of LH show that SIK inhibition stimulates Cyp17a1 in a concentration-dependent manner from 0.1 to 1 µM. Of note, at 3 µM, HG was less effective in inducing Cyp17a1 than at 1 µM, suggesting that higher concentrations of HG may have alternative unknown effects. Activation of adenyl cyclase with forskolin or emulation of increased intracellular cAMP with dbcAMP stimulated Cyp17a1 an effect that was also enhanced by the inhibition of SIK. Since the main target of cAMP is PKA, we used lentivirus to express constitutively active PKA (caPKA). Overexpression of caPKA was sufficient to stimulate testosterone production, an effect that was significantly augmented by SIK inhibition, suggesting that SIKs regulate factors downstream of PKA. This evidence shows that TCs express SIKs and reveal novel roles for SIKs in the regulation of TC function and androgen production. This information could contribute to uncovering therapeutic targets to treat hyperandrogenic diseases such as PCOS. Presentation: Friday, June 16, 2023

Impaired Functions of Human Granulosa Cell Line COV434 under Hypoxic and Inflammatory Conditions

Premature ovarian insufficiency (POI) affects 1% of women under 40 years old and represents one of the main causes of infertility in females of childbearing age. POI is a primary ovarian defect resulting from follicular depletion and/or ovarian dysfunction caused by a compromised ovarian somatic cell compartment. Etiologically, ovarian dysfunction could be caused by certain diseases, including infections and autoimmune disorders. There could also be iatrogenic factors such as chemotherapy, radiation, or surgery. The related surgical risks are due to the possibility of disrupting the blood supply to the ovary and/or a subsequent inflammatory reaction. To date, it is unclear whether and how the impaired oxygen delivery and inflammatory environment may influence the basic functions of human ovarian somatic cells. In this study, we used an immortalized human granulosa cell line (COV434) as a model to investigate the effect of exposure to low oxygen levels (hypoxia) and inflammatory conditions on granulosa cell proliferation, apoptosis, and steroidogenesis. The results showed that both hypoxia (5% O2) and proinflammatory cytokine treatment (a combination of TNF-α, IL-1β, IFN-γ and IL-6) significantly increased apoptosis, suppressed proliferation, and affected estradiol secretion in COV434 cells. Our data suggest that granulosa cells could be particularly sensitive to changes in the local environment caused by oxygen deprivation and chronic inflammation.

Pyridoxamine protects human granulosa cells against advanced glycation end-products-induced steroidogenesis disturbances.

Ovarian advanced glycation end-products (AGEs) accumulation is associated with ovarian granulosa cells (GCs) dysfunction. Vitamin B6 derivatives positively affected reproduction. The current study was conducted to elucidate the AGEs effects on human luteinized mural GCs steroidogenesis in the presence or absence of pyridoxamine (PM). Isolated GCs of 50 healthy women were divided into four parts and treated with media alone (Control), PM alone, or human glycated albumin (HGA) with/without PM. Main steroidogenic enzymes and hormones were assessed by qRT-PCR and ELISA. The AGE receptor (RAGE) protein was also determined using Western blotting. The non-toxic concentration of HGA increased the expression of RAGE, StAR, 3β-HSD, and 17β-HSD (P < 0.0001 for all) but decreased the expression of CYP19A1 at mRNA levels. The increased RAGE protein expression was also confirmed by western blot analysis. These effects resulted in declined estradiol (E2), slightly, and a sharp rise in progesterone (P4) and testosterone (T) levels, respectively. PM, on its own, ameliorated the HGA-altered enzyme expression and, thereby, corrected the aberrant levels of E2, P4, and T. These effects are likely mediated by regulating the RAGE gene and protein expression. This study indicates that hormonal dysfunctions induced by the AGEs-RAGE axis in luteinized GCs are likely rectified by PM treatment. This effect is likely acquired by reduced expression of RAGE. A better understanding of how AGEs and PM interact in ovarian physiology and pathology may lead to more targeted therapy for treating ovarian dysfunction.

ERK1/2-SOX9/FOXL2 axis regulates ovarian steroidogenesis and favors the follicular-luteal transition.

Estradiol and progesterone are the primary sex steroids produced by the ovary. Upon luteinizing hormone surge, estradiol-producing granulosa cells convert into progesterone-producing cells and eventually become large luteal cells of the corpus luteum. Signaling pathways and transcription factors involved in the cessation of estradiol and simultaneous stimulation of progesterone production in granulosa cells are not clearly understood. Here, we decipher that phosphorylated ERK1/2 regulates granulosa cell steroidogenesis by inhibiting estradiol and inducing progesterone production. Down-regulation of transcription factor FOXL2 and up-regulation of SOX9 by ERK underpin its differential steroidogenic function. Interestingly, the incidence of SOX9 is largely uncovered in ovarian cells and is found to regulate FOXL2 along with CYP19A1 and STAR genes, encoding rate-limiting enzymes of steroidogenesis, in cultured granulosa cells. We propose that the novel ERK1/2-SOX9/FOXL2 axis in granulosa cells is a critical regulator of ovarian steroidogenesis and may be considered when addressing pathophysiologies associated with inappropriate steroid production and infertility in humans and animals.

Salt-inducible kinases regulate androgen synthesis in theca cells by enhancing CREB signaling

Ovulation is the pinnacle of folliculogenesis, a process that requires an interplay between the oocyte, the granulosa cells, and the theca cells (TCs). TCs are the only source of ovarian androgens, which play a vital role in female fertility. However, abnormally elevated androgen levels reduce fertility. Therefore, uncovering novel mechanisms regulating androgen synthesis in TCs is of great significance. We have shown that salt-inducible kinases (SIKs) regulate granulosa cell steroidogenesis. Here, we investigated whether SIKs regulate androgen production in TCs. SIK2 and SIK3 were detected in the TCs of mouse ovaries and isolated TCs. Next, TCs in culture were treated with luteinizing hormone (LH) in the presence or absence of a highly specific SIK inhibitor. SIK inhibition enhanced the stimulatory effect of LH on steroidogenic gene expression and androgen production in a concentration-dependent manner. SIK inhibition alone stimulated the expression of steroidogenic genes and increased androgen production. Activation of adenylyl cyclase with forskolin or emulation of increased intracellular cyclic AMP levels stimulated steroidogenesis, an effect that was enhanced by the inhibition of SIK activity. The stimulatory effect of downstream targets of cyclic AMP was also significantly augmented by SIK inhibition, suggesting that SIKs control targets downstream cyclic AMP. Finally, it is shown that SIK2 knockout mice have higher circulating testosterone than controls. This evidence shows that TCs express SIKs and reveal novel roles for SIKs in the regulation of TC function and androgen production. This information could contribute to uncovering therapeutic targets to treat hyperandrogenic diseases.

Organophosphate Esters Disrupt Steroidogenesis in KGN Human Ovarian Granulosa Cells.

Organophosphate esters (OPEs) are used extensively as flame retardants and plasticizers and are found ubiquitously in the environment and human matrices. Previous studies suggested that exposure to some of these chemicals may disrupt the homeostasis of female sex hormones and have detrimental effects on female fertility. Here, we determined the effects of OPEs on the function of KGN ovarian granulosa cells. We hypothesized that OPEs alter the steroidogenic ability of these cells by dysregulating the expression of transcripts involved in steroid and cholesterol biosynthesis. KGN cells were exposed for 48 hours to 1 of 5 OPEs (1-50μM): triphenyl phosphate (TPHP), tris(methylphenyl) phosphate (TMPP), isopropylated triphenyl phosphate (IPPP), tert-butylphenyl diphenyl phosphate (BPDP), and tributoxyethyl phosphate (TBOEP), or to a polybrominated diphenyl ether flame retardant, 2,2',4,4' tetrabromodiphenyl ether (BDE-47), in the presence or absence of Bu2cAMP. OPEs increased the basal production of progesterone (P4) and 17β-estradiol (E2) and had either no effect or inhibited Bu2cAMP-stimulated P4 and E2 synthesis; exposure to BDE-47 had no effect. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed that OPEs (≥5μM) increased the basal expression of critical genes (STAR, CYP11A1, CYP19A1, HSD3B2, and NR5A1) involved in steroidogenesis; upon stimulation, the expression of all genes tested was downregulated. An overall inhibition in cholesterol biosynthesis was induced by OPEs, characterized by a downregulation in HMGCR and SREBF2 expression. TBOEP consistently showed the least effect. Therefore, OPEs perturbed steroidogenesis in KGN granulosa cells by targeting the expression of steroidogenic enzymes and cholesterol transporters; these effects may have an adverse impact on female reproduction.