Dysregulation of Cytochrome P450 17α-Hydroxylase Messenger Ribonucleic Acid Stability in Theca Cells Isolated from Women with Polycystic Ovary Syndrome

Abstract

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disorder characterized by ovarian hyperandrogenism. Theca interna cells isolated from the ovaries of women with PCOS are characterized by increased expression of cytochrome P450 17alpha-hydroxylase (CYP17) [steroid 17alpha-hydroxylase/17,20 lyase (P450c17)], a steroidogenic enzyme obligatory for the biosynthesis of androgens. Augmented expression of the gene encoding P450c17 (CYP17) in PCOS theca has been attributed, in part, to differential transcriptional regulation of the CYP17 promoter in normal and PCOS cells. The present studies examine whether CYP17 gene expression is also posttranscriptionally regulated at the level of mRNA stability in normal and PCOS theca cells maintained in long-term culture. Determination of endogenous CYP17 mRNA half-life by pharmacological inhibition of transcription demonstrated that the half-life of CYP17 mRNA increased 2-fold in PCOS theca cells, compared with normal theca cells. Forskolin treatment also prolonged CYP17 mRNA half-life in both normal and PCOS theca cells. In vitro mRNA degradation studies demonstrated that the 5'-untranslated region confers increased stability to CYP17 mRNA in PCOS theca cells and showed that the 5'-untranslated region of CYP17 also confers forskolin-stimulated stabilization of CYP17 mRNA. These studies indicate that a slower rate of CYP17 mRNA decay contributes to increased steady-state mRNA accumulation and augmented CYP17 gene expression in PCOS theca cells.

Hormonal regulation of cytochrome P450 aromatase mRNA stability in non-luteinizing bovine granulosa cells in vitro

“…In rat and human granulosa cells, cAMP was reported to have no effect on the stability of mRNA encoding FSH receptor, Cyp11a and StAR (Hum et al 1993, Kiriakidou et al 1996, Tano et al 1997, and had no effect on Cyp11a in the present study. Recently, it was shown that forskolin, an adenylyl cyclase stimulator, prolonged cytochrome P450 17a-hydroxylase mRNA stability in human theca cells (Wickenheisser et al 2005), which is consistent with the effects of cAMP observed on Cyp19 mRNA stability in the present study. The difference in mRNA stability in FSH-and cAMP-stimulated cells is interesting, as cAMP is the classical intracellular mediator of FSH action, including activation of protein kinase A and MAPK (Gonzalez-Robayna et al 2000, Cottom et al 2003.…”

“…These doses were chosen based on previous studies examining steroidogenic protein mRNAs (Genissel et al 2001, Wickenheisser et al 2005. Cells were cultured with FSH (AFP5332B; NHPP, Torrance, CA, USA; 1 ng/ml), insulin (100 ng/ml, without FSH) or dibutyryl-cAMP (cAMP; 300 mM), and transcription inhibitors were added on day 6.…”

Decreased myo-inositol to chiro-inositol (M/C) ratios and increased M/C epimerase activity in PCOS theca cells demonstrate increased insulin sensitivity compared to controls

“…Samples were then transferred to centrifuge tubes, with the original vial washed three times with HPLC grade H 2 O and dried in vacuo. Several 400 µL aliquots of H 2 O were added to the centrifuge vial CYP11 mRNA abundance results from both increased transactivation of the promoter and augmented mRNA stability in PCOS cells [20,29] [23]. Moreover the 5' untranslated region of CYP17A1 and CYP11A1 mRNA have been shown to confer increased mRNA half life in PCOS theca cells as compared to normal theca cells, thus increasing CYP17A1 and CYP11A1 expression and androgen production in PCOS theca cells [23,29].…”

Genetikai és epigenetikai faktorok polycystás ovarium szindróma esetén

“…Tanulmányukban szintén kimutatták, hogy az elhízással kapcsolatos gének (mint az FTO és a melanocortin receptor 4 gén -MC4R) szintén magasabb BMI-értékhez vezet PCOS-ben, de nem játszanak fontos szerepet a szindróma kialakulásában. Mivel a PCOS és elhízás között szoros kapcsolat van, érdemes lehet más, zsírmennyiséget befolyásoló gének eltérései-nek a vizsgálata, keresése, amelyek szerepet játszhatnak a PCOS kialakulásában [15][16][17][18][19].…”

“…Ez alakítja át a koleszterint pregnenolonná. CYP11A kandidáns gént vizsgálva nem találtak összefüggést az 5-ös allél esetén PCOS-sel, azonban összefüggést találtak a 4-es alléllel [18][19][20].…”