scholarly journals GATA4 Reduction Enhances 3′,5′-Cyclic Adenosine 5′-Monophosphate-Stimulated Steroidogenic Acute Regulatory Protein Messenger Ribonucleic Acid and Progesterone Production in Luteinized Porcine Granulosa Cells

Endocrinology ◽  
2008 ◽  
Vol 149 (11) ◽  
pp. 5557-5567 ◽  
Author(s):  
Yvonne Y. Hui ◽  
Holly A. LaVoie
Keyword(s):  
Granulosa Cells ◽  
Regulatory Protein ◽  
Steroidogenic Acute Regulatory Protein ◽  
Mrna Levels ◽  
Down Regulation ◽  
Lh Surge ◽  
Progesterone Production ◽  
Steroidogenic Acute Regulatory ◽  
Camp Induction ◽  
Star Gene

Previous studies with cultured granulosa cells implicated GATA4 in gonadotropin regulation of the steroidogenic acute regulatory protein (STAR) gene. Caveats to these prior studies exist. First, GATA4 levels are reduced in granulosa-luteal cells after the LH surge when GATA6 expression is relatively high. Second, STAR mRNA expression is negligible in granulosa cells until after the LH surge. Both exogenous GATA4 and GATA6 can transactivate STAR gene promoter constructs. We used an RNA interference (RNAi) approach to determine the contributions of GATA4 and GATA6 to cAMP analog regulation of the endogenous STAR gene in luteinizing granulosa cells. STAR mRNA was stimulated by cAMP under control RNAi conditions. Surprisingly, GATA4 reduction by its respective RNAi approximately doubled the cAMP induction of STAR mRNA. At 24 h cAMP treatment, this augmentation was abolished by co-down-regulation of GATA4+GATA6. GATA6 down-regulation by itself did not alter STAR mRNA levels. GATA4+GATA6 co-down-regulation elevated basal CYP11A mRNA at 24 h treatment but did not affect its induction by cAMP. Basal levels of HSD3B mRNA were reduced by GATA4 RNAi conditions leading to a greater fold induction of its mRNA by cAMP. Fold cAMP-stimulated progesterone production was enhanced by GATA4 down-regulation but not by GATA4+GATA6 co-down-regulation. These data implicate GATA6 as the facilitator in cAMP-stimulated STAR mRNA and downstream progesterone accumulation under reduced GATA4 conditions. Data also demonstrate that basal levels of GATA4/6 are not required for cAMP induction of the STAR gene. The altered ratio of GATA4 to GATA6 after ovulation may allow GATA6 to enhance STAR mRNA accumulation.

scholarly journals BMP15 Suppresses Progesterone Production by Down-Regulating StAR via ALK3 in Human Granulosa Cells

2013 ◽  
Vol 27 (12) ◽  
pp. 2093-2104 ◽  
Author(s):  
Hsun-Ming Chang ◽  
Jung-Chien Cheng ◽  
Christian Klausen ◽  
Peter C. K. Leung
Keyword(s):  
Granulosa Cells ◽  
Critical Role ◽  
Regulatory Protein ◽  
Granulosa Cell Tumor ◽  
Type I ◽  
Mrna Levels ◽  
Protein Levels ◽  
Human Granulosa Cells ◽  
Progesterone Production ◽  
Steroidogenic Acute Regulatory

In addition to somatic cell-derived growth factors, oocyte-derived growth differentiation factor (GDF)9 and bone morphogenetic protein (BMP)15 play essential roles in female fertility. However, few studies have investigated their effects on human ovarian steroidogenesis, and fewer still have examined their differential effects or underlying molecular determinants. In the present study, we used immortalized human granulosa cells (SVOG) and human granulosa cell tumor cells (KGN) to compare the effects of GDF9 and BMP15 on steroidogenic enzyme expression and investigate potential mechanisms of action. In SVOG cells, neither GDF9 nor BMP15 affects the mRNA levels of P450 side-chain cleavage enzyme or 3β-hydroxysteroid dehydrogenase. However, treatment with BMP15, but not GDF9, significantly decreases steroidogenic acute regulatory protein (StAR) mRNA and protein levels as well as progesterone production. These suppressive effects, along with the induction of Sma and Mad-related protein (SMAD)1/5/8 phosphorylation, are attenuated by cotreatment with 2 different BMP type I receptor inhibitors (dorsomorphin and DMH-1). Furthermore, depletion of activin receptor-like kinase (ALK)3 using small interfering RNA reverses the effects of BMP15 on SMAD1/5/8 phosphorylation and StAR expression. Similarly, knockdown of ALK3 abolishes BMP15-induced SMAD1/5/8 phosphorylation in KGN cells. These results provide evidence that oocyte-derived BMP15 down-regulates StAR expression and decreases progesterone production in human granulosa cells, likely via ALK3-mediated SMAD1/5/8 signaling. Our findings suggest that oocyte may play a critical role in the regulation of progesterone to prevent premature luteinization during the late stage of follicle development.

scholarly journals Luteinizing Hormone-Induced Extracellular-Signal Regulated Kinase Activation Differently Modulates Progesterone and Androstenedione Production in Bovine Theca Cells

Endocrinology ◽  
2005 ◽  
Vol 146 (7) ◽  
pp. 2903-2910 ◽  
Author(s):  
Kimihisa Tajima ◽  
Kumiko Yoshii ◽  
Shin Fukuda ◽  
Makoto Orisaka ◽  
Kaoru Miyamoto ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Regulatory Protein ◽  
Steroidogenic Acute Regulatory Protein ◽  
Mrna Levels ◽  
Theca Cells ◽  
Progesterone Production ◽  
Erk Phosphorylation ◽  
Steroidogenic Acute Regulatory ◽  
Kinase A

Abstract It has been reported that gonadotropins promoted phosphorylation of ERK/MAPK in granulosa cells. However, little is known about the effects of gonadotropin on ERK activity in theca cells. This study explores how LH/forskolin controls ERK phosphorylation in cultured bovine theca cells. Effects of ERK on steroidogenesis were also investigated. Phosphorylation of ERK in bovine theca cells was augmented by LH and forskolin in 5 min; it decreased thereafter below basal levels in 20 min. Nevertheless, phosphorylation of the ERK kinase, MEK, was unaffected. Addition of H89 (a protein kinase A inhibitor) significantly reduced the effect of LH/forskolin on ERK phosphorylation. A potent MEK inhibitor PD98059 eliminated ERK phosphorylation and augmented progesterone production concomitantly with the elevation of intracellular steroidogenic acute regulatory protein mRNA in LH/forskolin-stimulated theca cells. In contrast to progesterone production, androgen production was diminished significantly by inhibition of ERK with decreased intracellular P450c17 mRNA levels. Taking these results together, we conclude that LH/cAMP leads to phosphorylation of ERK in a biphasic manner through MEK-independent pathway in bovine theca cells. Protein kinase A-induced phosphatase could possibly contribute to the phosphorylation process. Furthermore, modulation of ERK phosphorylation involves control of thecal steroidogenesis via modulation of the expression of steroidogenic acute regulatory protein and P450c17.

scholarly journals The Imitation Switch Protein SNF2L Regulates Steroidogenic Acute Regulatory Protein Expression during Terminal Differentiation of Ovarian Granulosa Cells

2006 ◽  
Vol 20 (10) ◽  
pp. 2406-2417 ◽  
Author(s):  
Maribeth A. Lazzaro ◽  
David Pépin ◽  
Nazario Pescador ◽  
Bruce D. Murphy ◽  
Barbara C. Vanderhyden ◽  
...  
Keyword(s):  
Progesterone Receptor ◽  
Corpus Luteum ◽  
Chromatin Remodeling ◽  
Granulosa Cells ◽  
Regulatory Protein ◽  
Terminal Differentiation ◽  
Steroidogenic Acute Regulatory Protein ◽  
Luteal Cell ◽  
Steroidogenic Acute Regulatory ◽  
Star Gene

Abstract Luteinization is a complex process, stimulated by gonadotropins, that promotes ovulation and development of the corpus luteum through terminal differentiation of granulosa cells. The pronounced expression of the mammalian imitation switch (ISWI) genes, SNF2H and SNF2L, in adult ovaries prompted us to investigate the role of these chromatin remodeling proteins during follicular development and luteinization. SNF2H expression is highest during growth of preovulatory follicles and becomes less prevalent during luteinization. In contrast, both SNF2L transcript and SNF2L protein levels are rapidly increased in granulosa cells of the mouse ovary 8 h after human chorionic gonadotropin treatment, and continue to be expressed 36 h later within the functional corpus luteum. We demonstrate a physical interaction between SNF2L and the progesterone receptor A isoform, which regulates progesterone receptor-responsive genes required for ovulation. Moreover, chromatin immunoprecipitation demonstrated that, after gonadotropin stimulation, SNF2L is associated with the proximal promoter of the steroidogenic acute regulatory protein (StAR) gene, a classic marker of luteinization in granulosa cells. Interaction of SNF2L with the StAR promoter is required for StAR expression, because small interfering RNA knockdown of SNF2L prevents the activation of the StAR gene. Our results provide the first indication that ISWI chromatin remodeling proteins are responsive to the LH surge and that this response is required for the activation of the StAR gene and the overall development of a functional luteal cell.

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

2019 ◽  
Vol 31 (11) ◽  
pp. 1647
Author(s):  
Kristina Pogrmic-Majkic ◽  
Gordana Kosanin ◽  
Dragana Samardzija Nenadov ◽  
Svetlana Fa ◽  
Bojana Stanic ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Regulatory Protein ◽  
Growth Factor Receptor ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Peroxisome Proliferator Activated Receptor ◽  
Progesterone Production ◽  
Extracellular Signal ◽  
Epidermal Growth ◽  
Steroidogenic Acute Regulatory

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.

Acute regulation of the bovine gene for the steroidogenic acute regulatory protein in ovarian theca and adrenocortical cells

2000 ◽  
Vol 24 (1) ◽  
pp. 109-118 ◽  
Author(s):  
R Ivell ◽  
G Tillmann ◽  
H Wang ◽  
M Nicol ◽  
PM Stewart ◽  
...  
Keyword(s):  
Gene Transcription ◽  
Cell Cultures ◽  
Protein Biosynthesis ◽  
Regulatory Protein ◽  
Steroidogenic Acute Regulatory Protein ◽  
Mrna Levels ◽  
Adrenocortical Cells ◽  
Theca Cells ◽  
Steroidogenic Acute Regulatory ◽  
Star Gene

Upregulation of the steroidogenic acute regulatory protein (StAR) is implicated in the rapid synthesis and secretion of steroidogenic cells to produce steroids in response to stimulation by trophic hormones of the gonadal and stress axes. In the present study, we have assessed the kinetics of both StAR gene transcription and protein biosynthesis in primary cell cultures of bovine adrenocortical and ovarian theca cells, under conditions of acute stimulation by corticotrophin (ACTH) and luteinizing hormone (LH), respectively. In both cell systems, detectable upregulation of StAR gene transcription occurred within 1-2 h, reaching maxima at 4 h (theca cells) or 6 h (adrenocortical cells). mRNA levels returned rapidly to baseline, by 12 h or 24 h, respectively. Specific StAR protein levels were assessed by western blotting using a novel antibody raised against a bovine StAR peptide, and showed a similar fast upregulation, albeit delayed by 1-2 h compared with the mRNA. The response of the cultured theca cells was more acute than that of the adrenocortical cells, possibly reflecting the propensity of the LH receptor to desensitize rapidly, unlike the ACTH receptor. The primary bovine theca cell cultures were also used for fully homologous transfection studies using various deletion promoter-reporter constructs of the bovine StAR gene. Kinetic analysis of the results indicated that the acute transcriptional response resides within the proximal (-315 bp) promoter region, which includes two putative responsive elements for the steroidogenic factor-1. More distal promoter regions may be involved in modulating the specificity of expression by combining enhancer and inhibitory functions.

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