scholarly journals Valproate Potentiates Androgen Biosynthesis in Human Ovarian Theca Cells

Endocrinology ◽  
2004 ◽  
Vol 145 (2) ◽  
pp. 799-808 ◽  
Author(s):  
Velen L. Nelson-DeGrave ◽  
Jessica K. Wickenheisser ◽  
Jennifer E. Cockrell ◽  
Jennifer R. Wood ◽  
Richard S. Legro ◽  
...  
Keyword(s):  
Promoter Activity ◽  
Polycystic Ovary ◽  
Regulatory Protein ◽  
Histone H3 ◽  
Steroidogenic Acute Regulatory Protein ◽  
Ovary Syndrome ◽  
Theca Cells ◽  
Histone H3 Acetylation ◽  
Steroidogenic Acute Regulatory ◽  
H3 Acetylation

Abstract In patients with epilepsy, treatment with valproate (VPA) has been reported to be associated with polycystic ovary syndrome-like symptoms including weight gain, hyperandrogenemia, and hyperinsulinemia. We examined the effect of VPA on androgen biosynthesis in ovarian theca cells isolated from follicles of normal cycling women to determine whether the hyperandrogenemia reported with VPA treatment could be a result of direct effects of VPA on the ovary. In long-term cultures of theca cells treated for 72 h with sodium valproate (30–3000 μm), we observed an increase in basal and forskolin-stimulated dehydroepiandrosterone (DHEA), androstenedione, and 17α-hydroxyprogesterone production compared with control values. In contrast, low doses of VPA treatment (i.e. 30–300 μm) had no effect on basal and forskolin-stimulated progesterone production, whereas higher doses of VPA (1000–3000 μm) inhibited progesterone production. The most pronounced effect of VPA on androgen biosynthesis was observed in the dose range of 300-3000 μm, which represent therapeutic levels in the treatment of epilepsy and bipolar disorder. Western analyses demonstrated that VPA treatment increased both basal and forskolin-stimulated P450c17 and P450scc protein levels, whereas the amount of steroidogenic acute regulatory protein was unaffected. In transient transfection studies, VPA was found to increase P450 17α-hydroxylase and P450 cholesterol side-chain cleavage promoter activity, whereas steroidogenic acute regulatory protein promoter activity was unaffected. Consistent with the ability of VPA to act as a histone deacetylase (HDAC) inhibitor in other cell systems, VPA (500 μm) treatment was observed to increase histone H3 acetylation and P450 17α-hydroxylase mRNA accumulation. The HDAC inhibitor butyric acid (500 μm) similarly increased histone H3 acetylation and DHEA biosynthesis, whereas the VPA derivative valpromide (500 μm), which lacks HDAC inhibitory activity, had no effect on histone acetylation or DHEA biosynthesis. These data suggest that VPA-induced ovarian androgen biosynthesis results from changes in chromatin modifications (histone acetylation) that augment transcription of steroidogenic genes. These studies provide the first biochemical evidence to support a role for VPA in the genesis of polycystic ovary syndrome-like symptoms, and establish a direct link between VPA treatment and increased ovarian androgen biosynthesis.

scholarly journals Prostaglandin F2α Suppresses Rat Steroidogenic Acute Regulatory Protein Expression via Induction of Yin Yang 1 Protein and Recruitment of Histone Deacetylase 1 Protein

Endocrinology ◽  
2007 ◽  
Vol 148 (11) ◽  
pp. 5209-5219 ◽  
Author(s):  
Qiyuan Liu ◽  
Kathleen A. Merkler ◽  
Xiaohui Zhang ◽  
Mark P. McLean
Keyword(s):  
Protein Expression ◽  
Promoter Activity ◽  
Trichostatin A ◽  
Histone H3 ◽  
Prostaglandin F2α ◽  
Star Protein ◽  
Histone Deacetylase 1 ◽  
Yin Yang 1 ◽  
Steroidogenic Acute Regulatory ◽  
H3 Acetylation

Prostaglandin F2α (PGF2α) plays a pivotal role in ovarian luteolysis by inhibiting the expression of steroidogenic acute regulatory (StAR) protein, leading to a decrease in intracellular cholesterol transport and luteal steroid production. Previously we have demonstrated that the transcription factor Yin Yang 1 (YY1) bound to three regions in the StAR promoter in vitro and repressed promoter activity. This study further defined the YY1-mediated PGF2α effect on the inhibition of StAR protein expression through YY1 interaction with a single region in the StAR promoter in vivo. PGF2α consistently suppressed StAR mRNA and protein expression in cultured luteal cells in a dose-dependent manner. PGF2α also enhanced YY1 protein expression and binding to its cis-element in a time-dependent pattern that preceded the decline in StAR protein levels. The StAR promoter region bound by YY1 was also associated with histone deacetylase 1 (HDAC1). PGF2α treatment promoted HDAC1 binding to and suppressed the histone H3 acetylation in this region. On the contrary, YY1 knockdown decreased HDAC1 binding, increased histone H3 acetylation, enhanced StAR protein expression, and negated PGF2α effect on StAR protein expression. Luciferase assays showed that YY1 overexpression inhibited StAR promoter activity and the addition of a HDAC inhibitor, trichostatin A, abrogated the effect of YY1. Trichostatin A-treated luteal cells displayed increased StAR protein expression. These data indicate that PGF2α enhances a direct YY1/StAR promoter interaction and the recruitment of HDAC1 to the promoter, thereby preventing transcriptional activation of the StAR gene.

scholarly journals Salt-Inducible Kinase Is Involved in the ACTH/cAMP-Dependent Protein Kinase Signaling in Y1 Mouse Adrenocortical Tumor Cells

2001 ◽  
Vol 15 (8) ◽  
pp. 1264-1276 ◽  
Author(s):  
Xing-zi Lin ◽  
Hiroshi Takemori ◽  
Yoshiko Katoh ◽  
Junko Doi ◽  
Nanao Horike ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Promoter Activity ◽  
Regulatory Protein ◽  
Steroidogenic Acute Regulatory Protein ◽  
Side Chain ◽  
Mrna Levels ◽  
Steroidogenic Factor 1 ◽  
Side Chain Cleavage ◽  
Chain Cleavage ◽  
Steroidogenic Acute Regulatory

Abstract The involvement of salt-inducible kinase, a recently cloned protein serine/threonine kinase, in adrenal steroidogenesis was investigated. When Y1 mouse adrenocortical tumor cells were stimulated by ACTH, the cellular content of salt-inducible kinase mRNA, protein, and enzyme activity changed rapidly. Its level reached the highest point in 1–2 h and returned to the initial level after 8 h. The mRNA levels of cholesterol side-chain cleavage cytochrome P450 and steroidogenic acute regulatory protein, on the other hand, began to rise after a few hours, reaching the highest levels after 8 h. The salt-inducible kinase mRNA level in ACTH-, forskolin-, or 8-bromo-cAMP-treated Kin-7 cells, mutant Y1 with less cAMP-dependent PKA activity, remained low. However, Kin-7 cells, when transfected with a PKA expression vector, expressed salt-inducible kinase mRNA. Y1 cells that overexpressed salt-inducible kinase were isolated, and the mRNA levels of steroidogenic genes in these cells were compared with those in the parent Y1. The level of cholesterol side-chain cleavage cytochrome P450 mRNA in the salt-inducible kinase-overexpressing cells was markedly low compared with that in the parent, while the levels of Ad4BP/steroidogenic factor-1-, ACTH receptor-, and steroidogenic acute regulatory protein-mRNAs in the former were similar to those in the latter. The ACTH-dependent expression of cholesterol side-chain cleavage cytochrome P450- and steroidogenic acute regulatory protein-mRNAs in the salt-inducible kinase-overexpressing cells was significantly repressed. The promoter activity of the cholesterol side-chain cleavage cytochrome P450 gene was assayed by using Y1 cells transfected with a human cholesterol side-chain cleavage cytochrome P450 promoter-linked reporter gene. Addition of forskolin to the culture medium enhanced the cholesterol side-chain cleavage cytochrome P450 promoter activity, but the forskolin-dependently activated promoter activity was inhibited when the cells were transfected with a salt-inducible kinase expression vector. This inhibition did not occur when the cells were transfected with a salt-inducible kinase (K56M) vector that encoded an inactive kinase. The salt-inducible kinase’s inhibitory effect was also observed when nonsteroidogenic, nonAd4BP/steroidogenic factor-1 -expressing, NIH3T3 cells were used for the promoter assays. These results suggested that salt-inducible kinase might play an important role(s) in the cAMP-dependent, but Ad4BP/steroidogenic factor-1-independent, gene expression of cholesterol side-chain cleavage cytochrome P450 in adrenocortical cells.

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