Progesterone Production In Granulosa Cells Research Articles

Characterization of the hypothalamo–pituitary–gonadal axis in low and high egg producing turkey hens

Variation in egg production exists in commercial turkey hens, with low egg producing hens (LEPH) costing more per egg produced than high egg producing hens (HEPH). Egg production correlates with ovulation frequency, which is governed by the hypothalamic–pituitary–gonadal (HPG) axis. Ovulation is stimulated by a preovulatory surge (PS) of progesterone and luteinizing hormone, triggered by gonadotropin releasing hormone release and inhibited by gonadotropin inhibiting hormone. Differences between LEPH and HEPH were characterized by determining HPG axis plasma hormone profiles and mRNA levels for key genes, both outside and inside of the PS (n = 3 per group). Data were analyzed with a 2-way ANOVA using the mixed models procedure of SAS. In the HPG axis, plasma progesterone levels were not affected by egg production level but were elevated during the PS. In contrast, plasma estradiol levels were higher in HEPH than in LEPH but were not associated with the PS. LEPH exhibited decreased gene expression associated with ovulation stimulation and increased gene expression associated with ovulation inhibition in the hypothalamus and pituitary. In ovarian follicle cells, LEPH displayed decreased gene expression associated with progesterone, androgen, and estradiol production in the F1 follicle granulosa cells, F5 theca interna cells, and small white follicle cells, respectively. Different degrees of stimulation and inhibition within all tissues of the HPG axis were noted between LEPH and HEPH turkey hens, with HEPH showing higher expression of genes related to ovulation and steroidogenesis.

Androgens Modulate Rat Granulosa Cell Steroidogenesis.

Paracrine interactions between ovarian theca-interstitial cells (TICs) and granulosa cells (GCs) play an important role in the regulation of follicular steroidogenesis. Androgens serve as substrates for aromatization as well as affect GC function. This study evaluated the effects of co-culture of GC with TICs and the role of testosterone (T) and 5-alpha-dihydrotestosterone (DHT), and estradiol (E2) in modulation of GC expression of genes involved in the production of progesterone: 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase (Hsd3b) and cholesterol side-chain cleavage (Cyp11). GCs obtained from immature Sprague-Dawley rats and were cultured in chemically defined media without or with TICs, DHT, or T. Hsd3b and Cyp11 transcripts were analyzed by qt-PCR. Co-culture of GCs with TICs stimulated Hsd3b and CYP11 expression in GCs. DHT and T induced a concentration-dependent upregulation of Hsd3b and CYP11 expression, as well as increased progesterone concentrations in spent media. E2 also increased expression of Hsd3b, and Cyp11. Effects of androgens were abrogated in the presence of an anti-androgen bicalutamide and the antiestrogen ICI 182780 (ICI). In conclusion, present findings demonstrate that androgens upregulate production of progesterone in GCs; these effects are likely due to a combination of direct action on androgen receptors and effects mediated by estrogen receptors.

Effects of recombinant goose adiponectin on steroid hormone secretion in Huoyan geese ovarian granulosa cells

Adiponectin is an adipokine associated with the regulation of reproductive processes. To determine whether recombinant goose adiponectin contributes to the goose ovarian steroidogenesis, the native and then purified goose recombinant adiponectin protein was produced using recombinant DNA technologies. The effect of recombinant adiponectin on the progesterone (P4) and estradiol (E2) production in Huoyan geese ovarian granulosa cells was examined. Furthermore, the effect of recombinant adiponectin (2.5 μg/mL) on the abundance of StAR (steroidogenic acute regulatory protein), CYP11A1 (cytochrome P450scc, cholesterol side-chain cleavage enzyme) and CYP19A1 (cytochrome P450 aromatase) mRNA and protein in granulosa cells was evaluated. Results indicate that a 24-h treatment with recombinant adiponectin (2.5 μg/mL) affected P4 and E2 production by geese ovarian granulosa cells by stimulating P4 production (P < 0.01) and weakly inhibiting E2 production (P > 0.05). Furthermore, when the results with treatment were compared to when there was not adiponectin treatment, the abundance of StAR and CYP11A1 mRNA was greater (P < 0.05) while the CYP19A1 mRNA slightly decreased (P > 0.05). In addition, the fluorescence intensity of StAR tended to be greater compared to PBS-treated (P < 0.05) and control groups (P > 0.05) and StAR protein abundance was greater (P < 0.05) compared to the other two groups. The fluorescence intensity and protein abundances of CYP11A1 increased (P < 0.05) while those for CYP19A1 tended to decrease (P > 0.05) after adiponectin treatment. The results indicate recombinant goose adiponectin affects steroidogenesis and/or hormone secretion of geese ovarian granulosa cells. There may, therefore, be important functions of adiponectin in goose reproductive physiology.

Growth differentiation factor 9 promotes follicle-stimulating hormone-induced progesterone production in chicken follicular granulosa cells

The function of oocyte-derived growth differentiation factor 9 (GDF9) in ovarian follicles has thus far been poorly defined in avian species compared with the defined function in mammals. Our aim here is to investigate the effects of GDF9 on steroidogenesis and on chicken ovarian granulosa cell (GC) mitosis. Primary GCs from both prehierarchical (6–8 mm in diameter, phGCs) and preovulatory follicles (F1–F5, poGCs) were cultured in the presence or absence of the GDF9 protein. The progesterone (P4) levels in the culture medium were then measured by radioimmunoassay (RIA), and the expression levels of steroidogenesis genes were detected by quantitative PCR. We found that GDF9 alone showed no significant effect on the P4 levels by regulating the expression of steroidogenesis genes, such as STAR, CYP11A1 and HSD3B. Further experiments indicated that GDF9 promoted follicle-stimulating hormone (FSH)-induced P4 production and STAR expression. GDF9 also rescued the FSH-induced decrease of FSH receptor (FSHR) expression but had no effect on the forskolin-induced P4, STAR and forskolin-inhibited FSHR expression levels, suggesting that GDF9 might achieve its regulatory role of P4 by enhancing FSHR and STAR expression. In addition, GDF9 also promoted GC cell cycle progression, regulated the gene transcription of related genes, potentiated DNA replication and inhibited apoptosis. Interestingly, these effects differed between the phGCs and the poGCs. To our knowledge, this is the first report that illustrates the function of GDF9 on chicken GCs and the effects on ovarian steroidogenesis. Our findings highlight the regulation of central oocytes on the surrounding granulosa cells and emphasize the interaction between paracrine signals and endocrine hormones on ovarian progesterone production; these findings contribute to the understanding of the development of avian ovarian follicles.

Rosiglitazone increases expression of steroidogenic acute regulatory protein and progesterone production through PPARγ-EGFR-ERK1/2 in human cumulus granulosa cells.

The mechanism by which rosiglitazone (ROSI: a thiazolidinedione (TZD)) affects steroid production in undifferentiated human granulosa cells is not known. In this study, cultured human cumulus granulosa cells were exposed to ROSI and pharmacological inhibitors of the extracellular signal-regulated kinase 1/2 (ERK1/2), epidermal growth factor receptor (EGFR) and peroxisome proliferator-activated receptor gamma (PPARγ) signalling pathways. Expression of progesterone biosynthetic enzymes, PPARγ and PPARα, progesterone production and ERK1/2 activation were analysed. After 48h, 30μM ROSI increased STAR, 3βHSD and PPARγ mRNA and elevated progesterone production in human cumulus granulosa cells. Addition of ERK1/2 (U0126), EGFR (AG1478) and PPARγ (GW9662) inhibitors prevented the ROSI-induced STAR mRNA expression and progesterone production after 48h. Inhibition of PPARγ, but not EGFR or ERK1/2, decreased the PPARγ mRNA levels induced by ROSI in human cumulus granulosa cells after 48h. On the other hand, U0126 and GW9662 prevented the ROSI-induced increase in PPARγ transcripts after 6h. Western blot analysis showed that ROSI induced a rapid ERK1/2 activation, which was prevented by inhibition of ERK1/2, EGFR and PPARγ in human cumulus granulosa cells. Overall, these data suggested that PPARγ, EGFR and ERK1/2 were involved in the stimulatory effect of ROSI on STAR expression and progesterone production in undifferentiated human cumulus granulosa cells.

Association between Vitamin D Level and Polycystic Ovarian Syndrome in Premenopausal Iraqi Women

Poly cystic ovarian syndrome (PCOS) is one of the commonest endocrine disorders in young age group female (with a prevalence of 6–10% in the general population). “PCOS is characterized by the following: ovulatory dysfunction resulting in oligo-amenorrhea and/or anovulation, hyperandrogenism and/or hirsutism and the presence of polycystic ovarian morphology by ultrasound”. “Vitamin D also plays a physiologic role in reproduction including” ovarian follicular development and luteinization via altering anti Mullerian hormone (AMH)”, signaling, “follicle-stimulating hormone sensitivity and progesterone production in human granulosa cells.” the aim of this study was to determine” whether “serum levels of vitamin D” were different between diseased (PCOS) and non-diseased women and; to determine whether its deficiency is associated with, metabolic and endocrine dysregulations “in PCOS affected females”.a case-control prospective descriptive clinical study. Study setting: Obstetric and Pediatric Teaching Hospital in Al-Ramadi/Iraq. Patient and Methods: during the period from JAN 2018 to SEP 2018. It was included 80 women diagnosed with PCOS based on Rotterdam criteria and 20 fertile women without PCOS. The patient's age were 18–45 years excluding the patients who were on hormonal replacement therapy for last 3months, had endocrine or chronic hepatic or renal disorders, and women that take vitamin D for last six months. Other parameters were recorded; the weight and height of all patients and control group (calculating the BMI) and investigated for serum random blood sugar and vitamin D level using ELISA technique.

Effects of endocrine disruptors over progesterone production in human granulosa cells

Effects of endocrine disruptors over progesterone production in human granulosa cells

Vitamin D3 regulates steroidogenesis in granulosa cells through AMP-activated protein kinase (AMPK) activation in a mouse model of polycystic ovary syndrome.

Polycystic ovarian syndrome (PCOS) is an endocrine disorder of women in reproductive age. This disorder is partly related to disruption in steroidogenesis pathway and dysregulation of estradiol and progesterone production in granulosa cells of polycystic ovaries. Previously, we have shown that vitamin D3 could modulate steroidogenesis pathway in PCOS granulosa cells. In this study, we investigate the molecular mechanism of vitamin D3 in regulation of steroidogenesis pathway. We have shown that vitamin D3 has a modulating role in steroidogenesis pathway of granulosa cells by regulation of AMP-activated protein kinase (AMPK) as an underlying molecular mechanism in mouse polycystic ovary.

The impact of bisphenol S on bovine granulosa and theca cells.

Bisphenol S (BPS) is an endocrine-disrupting chemical with multiple potential mechanisms of action, including as an oestrogen receptor agonist. BPS is increasingly used in plastics and thermal receipts as a substitute for bisphenol A, which has been phased out due to concerns about human health implications. The ability of BPS to alter female reproductive function in mammals has not been widely studied, despite the importance of normal hormone signalling for female reproduction. The aim of this study was to investigate how BPS (in a wide range of doses, including very low doses) affects granulosa cell and theca cell steroid hormone production and cell viability in the bovine. Granulosa cell oestradiol production was stimulated when cells were exposed to 100μM BPS under basal conditions, but there was no effect of BPS when cells were stimulated with follicle-stimulating hormone (FSH). Additionally, there was no effect of BPS on granulosa cell progesterone production or cell viability under basal or FSH-stimulated conditions. BPS did not affect theca cell androstenedione or progesterone production, or theca cell viability under basal or luteinizing hormone-stimulated conditions. This study suggests for the first time that BPS may alter oestradiol production by bovine granulosa cells, albeit at a concentration that is unlikely to be physiologically relevant. Further studies are needed to determine the effects of BPS on the bovine oocyte and on other functions of follicular cells.

Assessment of Vitamin D Levels in Women with Polycystic Ovarian Syndrome

Background: polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, with a prevalence of 6–10% in the general population. PCOS is characterized by the following: ovulatory dysfunction resulting in oligo-amenorrhea and/or anovulation, hyperandrogenism and/or hirsutism and the presence of polycystic ovarian morphology by ultrasound. Vitamin D also plays a physiologic role in reproduction including ovarian follicular development and luteinization via altering anti-Mullerian hormone (AMH), signaling, follicle-stimulating hormone sensitivity and progesterone production in human granulosa cells. Aim of the Work: this study aimed to compare levels of vitamin D in women with PCOS and healthy fertile women. Patient and Methods: this case control study was conducted in Ain Shams Maternity hospital in outpatient infertility clinics and family planning clinic during the period from March 2017 to October 2017. It was included 40 women diagnosed with PCOS based on Rotterdam criteria and 40 fertile women without PCOS who were recruited from family planning clinic. Results: 25(OH) vitamin-D level was significantly lower in PCOS group than in the control group. Conclusion: 25(OH) vitamin-D was significantly lower in PCOS group than in the control group, but not sufficient to be a diagnostic tool for PCOS. Recommendation: larger studies are still needed to clarify the rule of vitamin D in infertility.

Bisphenol A decreases progesterone synthesis by disrupting cholesterol homeostasis in rat granulosa cells

Bisphenol A (BPA) is an endocrine disruptor used in a variety of consumer products. Exposure to BPA leads to alterations in steroidogenesis of ovarian granulosa cells. Here, we analyzed the mechanism by which BPA alters progesterone biosynthesis in immature rat granulosa cells. BPA increased expression of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme and 3β-hydroxysteroid dehydrogenase in granulosa cells; however, BPA prevented the basal and the FSH-induced progesterone production. BPA caused sequestration of cholesterol to the perinuclear area, as evident by the Filipin staining. BPA decreased mRNA expression of ATP binding cassette transporter-A1 (Abca1) and increased level of sterol regulatory element binding protein 1. Addition of exogenous cell-permeable cholesterol restored the effect of BPA on Abca1 and Star mRNA expression and partially reversed BPA's effect on progesterone production. These results indicate that exposure to BPA disrupts cholesterol homeostasis leading to decreased progesterone production in immature rat granulosa cells.

Effects of nonglycosylated and glycosylated prolactin on basal and gonadotropin-stimulated steroidogenesis in chicken ovarian follicles

In galliformes, the circulating isoform of prolactin (PRL) significantly changes during different reproductive states. However, the role of the major isoform (glycosylated PRL [G-PRL]) in ovarian steroidogenesis is unknown. The present study aimed to compare the effects of nonglycosylated (NG-) and G-PRL on basal and gonadotropin-stimulated estradiol (E2) and progesterone (P4) production in granulosa cells or follicular walls of chicken of different size class follicles. In the initial experiment, granulosa cells of preovulatory F3-F1 and prehierarchical 6- to 8-mm follicles were incubated for 24 h with different concentrations of NG- or G-PRL (0, 1, 10, 100, or 1,000 ng/mL). In the subsequent experiments, these categorized granulosa cells and follicular walls of prehierarchical 4–6, 2–4, and <2-mm follicles were incubated for 24 h in the absence and presence of 10-ng/mL FSH or LH, or in combination with different concentrations of NG- or G-PRL (10, 100, or 1,000 ng/mL). We observed that lower levels of NG-PRL induced (P < 0.05) E2 and P4 secretion in granulosa cells of either preovulatory or prehierarchical follicles, but at higher levels, this effect was reduced. In contrast, G-PRL promoted (P < 0.05) basal E2 and P4 secretion in preovulatory granulosa cells but was inhibitory (P < 0.05) in prehierarchical granulosa cells. Results obtained by real-time quantitative PCR (qPCR) demonstrated that these effects were mediated through modulation of the expression of StAR, CYP11A1, CYP19A1, and 3β-HSD. Furthermore, G-PRL was less potent than NG-PRL in inhibiting FSH- or LH-stimulated E2 and P4 production in granulosa cells of preovulatory follicles, whereas NG-PRL enhanced (P < 0.05) but G-PRL reduced (P < 0.05) FSH-induced P4 production in those of prehierarchical follicles. In follicular walls from each group of prehierarchical 4–6, 2–4, and <2-mm follicles, NG- and G-PRL had both stimulatory and inhibitory influences on the actions of FSH on E2 and P4 secretion, but both suppressed (P < 0.05) LH-induced E2 and P4 secretion except for the synergistic effects of LH and G-PRL on P4 secretion by follicular walls of the follicles of 4–6 mm. Taken together, these results suggest that both NG- and G-PRL are biologically active in regulating basal and gonadotropin-stimulated E2 and P4 production in chicken ovarian follicles. However, their effects are different depending on the concentration, the type of gonadotropin (FSH or LH), and the stage of follicle development.

ATF6 knockdown decreases apoptosis, arrests the S phase of the cell cycle, and increases steroid hormone production in mouse granulosa cells.

Activating transcription factor 6 (ATF6), a sensor protein located in the endoplasmic reticulum (ER) membrane, is an important factor in the ER stress signaling pathway. ER stress is known to be involved in folliculogenesis, follicular growth, and ovulation; however, the physiological function of ATF6 in mouse granulosa cells remains largely unknown. The aim of this study was to assess the role of ATF6 in mouse granulosa cells with respect to apoptosis, the cell cycle, and steroid hormone production, as well as several key genes related to follicular development, via RNA interference, immunohistochemical staining, real-time quantitative PCR, Western blotting, flow cytometry, terminal deoxynucleotidyltransferase-mediated deoxy-UTP nick end labeling (TUNEL) assay, and ELISA. Immunohistochemical staining revealed that ATF6 was extensively distributed in the granulosa cells of various ovarian follicles and oocytes in adult female mice. FSH or LH treatment significantly increased ATF6 protein levels in mouse granulosa cells. In the meantime, a recombinant plasmid was used to deplete ATF6 successfully using short hairpin RNA-mediated interference technology, which was verified at both the mRNA and protein levels. Flow cytometry and TUNEL assay analysis indicated that ATF6 depletion decreased apoptosis and arrested the S phase of the cell cycle in mouse granulosa cells. Consistent with these results, p53, caspase-3, B cell lymphoma 2 (Bcl-2)-associated X protein, CCAAT-enhancer-binding protein homologous protein, cyclin A1, cyclin B1, and cyclin D2 mRNA expression decreased, whereas Bcl-2 and glucose-regulated protein 78 kDa mRNA expression increased. Interestingly, ATF6 knockdown obviously increased progesterone and estradiol production in mouse granulosa cells. Cytochrome P450 1b1 (Cyp1b1) mRNA levels were downregulated, whereas Cyp11a1, steroidogenic acute regulatory, and Cyp19a1 mRNA levels were upregulated, in keeping with the changes in steroid hormones. Furthermore, ATF6 disruption remarkably increased insulin-like growth factor binding protein4 (Igfbp4) expression and decreased hyaluronan synthase 2 (Has2), prostaglandin-endoperoxide synthase 2 (Ptgs2), and prostaglandin F receptor (Ptgfr) expression in mouse granulosa cells, which are proteins crucial for follicular development. But, after treating with tunicamycin, the levels of Has2, Ptgs2, and Ptgfr increased relatively, whereas Igfbp4 expression decreased. Collectively, these results imply that ATF6, as a key player in ER stress signaling, may regulate apoptosis, the cell cycle, steroid hormone synthesis, and other modulators related to folliculogenesis in mouse granulosa cells, which may indirectly be involved in the development, ovulation, and atresia of ovarian follicles by affecting the physiological function of granulosa cells. The present study extends our understanding and provides new insights into the physiological significance of ATF6, a key signal transducer of ER stress, in ovarian granulosa cells.

Effects of angiogenin on granulosa and theca cell function in cattle

Angiogenin is a member of the ribonuclease A superfamily of proteins that has been implicated in stimulating angiogenesis but whether angiogenin can directly affect ovarian granulosa or theca cell function is unknown. Therefore, the objective of these studies was to determine the effect of angiogenin on proliferation and steroidogenesis of bovine granulosa and theca cells. In experiments 1 and 2, granulosa cells from small (1 to 5 mm diameter) follicles and theca cells from large (8 to 22 mm diameter) follicles were cultured to evaluate the dose-response effect of recombinant human angiogenin on steroidogenesis. At 30 and 100 ng/ml, angiogenin inhibited (P<0.05) granulosa cell progesterone production and theca cell androstenedione production but did not affect (P>0.10) granulosa cell estradiol production or theca cell progesterone production, and did not affect numbers of granulosa or theca cells. In experiments 3 and 4, granulosa and theca cells from both small and large follicles were cultured with 300 ng/ml of angiogenin to determine if size of follicle influenced responses to angiogenin. At 300 ng/ml, angiogenin increased large follicle granulosa cell proliferation but decreased small follicle granulosa cell progesterone and estradiol production and large follicle theca cell progesterone production. In experiments 5 and 6, angiogenin stimulated (P<0.05) proliferation and DNA synthesis in large follicle granulosa cells. In experiment 7, 300 ng/ml of angiogenin increased (P<0.05) CYP19A1 messenger RNA (mRNA) abundance in granulosa cells but did not affect CYP11A1 mRNA abundance in granulosa or theca cells and did not affect CYP17A1 mRNA abundance in theca cells. We conclude that angiogenin appears to target both granulosa and theca cells in cattle, but additional research is needed to further understand the mechanism of action of angiogenin in granulosa and theca cells, as well as its precise role in folliculogenesis.

A Potential Role for Endoplasmic Reticulum Stress in Progesterone Deficiency in Obese Women.

Obesity in reproductive-aged women is associated with a shorter luteal phase and lower progesterone levels. Lipid accumulation in follicles of obese women compromises endoplasmic reticulum (ER) function, activating ER stress in granulosa cells. We hypothesized that ER stress activation in granulosa-lutein cells (GLCs) would modulate progesterone production and contribute to obesity-associated progesterone deficiency. Pretreatment with an ER stress inducer, tunicamycin or thapsigargin, inhibited human chorionic gonadotropin (hCG)-stimulated progesterone production in cultured human GLCs. Pretreatment of human GLCs with tunicamycin inhibited hCG-stimulated expression of steroidogenic acute regulatory protein (StAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) messenger RNAs (mRNAs) without affecting expression of cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), as determined by real-time quantitative polymerase chain reaction. Pretreatment with tunicamycin also inhibited hCG-stimulated expression of StAR protein and 3β-HSD enzyme activity in cultured human GLCs, as determined by Western blot analysis and an enzyme immunoassay, respectively, but did not affect hCG-induced intracellular 3',5'-cyclic adenosine monophosphate accumulation. Furthermore, tunicamycin attenuated hCG-induced protein kinase A and extracellular signal-regulated kinase activation, as determined by Western blot analysis. In vivo administration of tunicamycin to pregnant mare serum gonadotropin-treated immature mice prior to hCG treatment inhibited the hCG-stimulated increase in serum progesterone levels and hCG-induced expression of StAR and 3β-HSD mRNA in the ovary without affecting serum estradiol levels or the number of corpora lutea. Our findings indicate that ER stress in the follicles of obese women contributes to progesterone deficiency by inhibiting hCG-induced progesterone production in granulosa cells.

Fractalkine restores the decreased expression of StAR and progesterone in granulosa cells from patients with polycystic ovary syndrome

Low progesterone levels are associated with luteal phase deficiency in women with polycystic ovary syndrome (PCOS). The mechanisms regulating progesterone biosynthesis in the granulosa cells from women with PCOS is largely unknown. Fractalkine is expressed in human ovaries, and is reported to regulate progesterone production in granulosa cells of healthy women. In the current study, we aimed to examine the role of fractalkine in women with PCOS. Reduced fractalkine levels were found in follicular fluid and granulosa cells, accompanied by decreased progesterone production and reduced steroidogenic acute regulatory protein (StAR) expression in the granulosa cells of patients with PCOS. Administration of fractalkine reversed the inhibition of progesterone and StAR expression. The mechanism mediating these effects may be associated with the inhibition of ERK activity in the granulosa cells from women with PCOS. Our findings revealed that fractalkine regulated steroidogenesis in follicular granulosa cells of women with PCOS.

Amphiregulin mediates hCG-induced StAR expression and progesterone production in human granulosa cells.

Progesterone plays critical roles in maintaining a successful pregnancy at the early embryonic stage. Human chorionic gonadotropin (hCG) rapidly induces amphiregulin (AREG) expression. However, it remains unknown whether AREG mediates hCG-induced progesterone production. Thus, the objective of this study was to investigate the role of AREG in hCG-induced progesterone production and the underlying molecular mechanism in human granulosa cells; primary cells were used as the experimental model. We demonstrated that the inhibition of EGFR and the knockdown of AREG abolished hCG-induced steroidogenic acute regulatory protein (StAR) expression and progesterone production. Importantly, follicular fluid AREG levels were positively correlated with progesterone levels in the follicular fluid and serum. Treatment with AREG increased StAR expression and progesterone production, and these stimulatory effects were abolished by EGFR inhibition. Moreover, activation of ERK1/2, but not PI3K/Akt, signaling was required for the AREG-induced up-regulation of StAR expression and progesterone production. Our results demonstrate that AREG mediates hCG-induced StAR expression and progesterone production in human granulosa cells, providing novel evidence for the role of AREG in the regulation of steroidogenesis.

Bisphenol A stimulates steroidogenic acute regulatory protein mRNA expression and progesterone production in rat immature granulosa cells

Bisphenol A stimulates steroidogenic acute regulatory protein mRNA expression and progesterone production in rat immature granulosa cells

BMP4 and BMP7 Suppress StAR and Progesterone Production via ALK3 and SMAD1/5/8-SMAD4 in Human Granulosa-Lutein Cells.

Adequate production of progesterone by the corpus luteum is critical to the successful establishment of pregnancy. In animal models, bone morphogenetic protein (BMP) 4 and BMP7 have been shown to suppress either basal or gonadotropin-induced progesterone production, depending on the species examined. However, the effects of BMP4 and BMP7 on progesterone production in human granulosa cells are unknown. In the present study, we used immortalized (SVOG) and primary human granulosa-lutein cells to investigate the effects of BMP4 and BMP7 on steroidogenic acute regulatory protein (StAR) expression and progesterone production and to examine the underlying molecular mechanism. Treatment of primary and immortalized human granulosa cells with recombinant BMP4 or BMP7 decreased StAR expression and progesterone accumulation. In SVOG cells, the suppressive effects of BMP4 and BMP7 on StAR expression were blocked by pretreatment with inhibitors of activin receptor-like kinase (ALK)2/3/6 (dorsomorphin) or ALK2/3 (DMH1) but not ALK4/5/7 (SB-431542). Moreover, small interfering RNA-mediated depletion of ALK3, but not ALK2 or ALK6, reversed the effects of BMP4 and BMP7 on StAR expression. Likewise, BMP4- and BMP7-induced phosphorylation of SMAD 1/5/8 was reversed by treatment with DMH1 or small interfering RNA targeting ALK3. Knockdown of SMAD4, the essential common SMAD for BMP/TGF-β signaling, abolished the effects of BMP4 and BMP7 on StAR expression. Our results suggest that BMP4 and BMP7 down-regulate StAR and progesterone production via ALK3 and SMAD1/5/8-SMAD4 signaling in human granulosa-lutein cells.

Lysosomes are involved in induction of steroidogenic acute regulatory protein (StAR) gene expression and progesterone synthesis through low-density lipoprotein in cultured bovine granulosa cells

Progesterone is an important steroid hormone in the regulation of the bovine estrous cycle. The steroidogenic acute regulatory protein (StAR) is an indispensable component for transporting cholesterol to the inner mitochondrial membrane, which is one of the rate-limiting steps for progesterone synthesis. Low-density lipoprotein (LDL) supplies cholesterol precursors for progesterone formation, and the lysosomal degradation pathway of LDL is essential for progesterone biosynthesis in granulosa cells after ovulation. However, it is currently unknown how LDL and lysosomes coordinate the expression of the StAR gene and progesterone production in bovine granulosa cells. Here, we investigated the role of lysosomes in LDL-treated bovine granulosa cells. Our results reported that LDL induced expression of StAR messenger RNA and protein as well as expression of cholesterol side-chain cleavage cytochrome P-450 (CYP11A1) messenger RNA and progesterone production in cultured bovine granulosa cells. The number of lysosomes in the granulosa cells was also significantly increased by LDL; whereas the lysosomal inhibitor, chloroquine, strikingly abolished these LDL-induced effects. Our results indicate that LDL promotes StAR expression, synthesis of progesterone, and formation of lysosomes in bovine granulosa cells, and lysosomes participate in the process by releasing free cholesterol from hydrolyzed LDL.