Growth differentiation factor-9 inhibits 3'5'-adenosine monophosphate-stimulated steroidogenesis in human granulosa and theca cells.
Growth differentiation factor-9 (GDF-9), a member of the transforming growth factor superfamily, modulates the development and function of granulosa and theca cells. Targeted deletion of GDF-9 in the mouse revealed that GDF-9 was essential for the establishment of the thecal cell layer during early folliculogenesis. During later stages of follicular development, the roles of GDF-9 are less well understood, but it has been postulated that oocyte-derived GDF-9 may prevent premature luteinization of follicular cells, based on its ability to modulate steroidogenesis by rodent ovarian cells. In the rodent, GDF-9 is expressed solely by the oocyte from the early primary follicular stage through ovulation. Recent studies in the rhesus monkey demonstrated that granulosa cells express GDF-9, suggesting a broader role for this protein in ovarian function in primates. We examined the effect of recombinant GDF-9 on proliferating human granulosa and thecal cell steroidogenesis and the expression of steroidogenic acute regulatory protein (StAR), P450 side-chain cleavage, and P450 aromatase. We also examined granulosa cell GDF-9 expression by quantitative RT-PCR and by Western analysis. GDF-9 inhibited 8-Br-cAMP-stimulated granulosa progesterone synthesis by approximately 40%, but did not affect basal progesterone production. Concordant with reduced steroid production, 8-Br-cAMP-stimulated StAR protein expression was reduced approximately 40% in granulosa cells, as were expression of StAR mRNA and StAR promoter activity. Additionally, GDF-9 inhibited 8-Br-cAMP-stimulated expression of P450 side-chain cleavage and P450 aromatase. Human granulosa cells expressed GDF-9, as determined by RT-PCR and Western analysis. Treatment of human thecal cells with GDF-9 blocked forskolin-stimulated progesterone, 17alpha-hydroxyprogesterone, and dehydroepiandrosterone synthesis. Thecal cells exhibited greater sensitivity to GDF-9, suggesting that this cell may be a primary target of GDF-9. Moreover, GDF-9 increased thecal cell numbers during culture, but had no effect on granulosa cell growth. Our findings implicate GDF-9 in the modulation of follicular steroidogenesis, especially theca cell function. Because GDF-9 mRNA and protein are detectable in granulosa-lutein cells after the LH surge, the concept of GDF-9 as a solely oocyte-derived luteinization inhibitor needs to be reevaluated.
Yamamoto
Noriko
N
Center for Research on Reproduction and Women's Health, University of Pennsylvania Medical Center, 421 Curie Boulevard, Philadelphia, PA 19104, USA.
Christenson
Lane K
LK
McAllister
Jan M
JM
Strauss
Jerome F
JF
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000249:Adenosine Monophosphate / Q000494:pharmacology*; D055430:Bone Morphogenetic Protein 15; D002478:Cells, Cultured; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D055429:Growth Differentiation Factor 9; D006133:Growth Substances / Q000235:genetics / Q000494:pharmacology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D010750:Phosphoproteins / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D013256:Steroids / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D013799:Theca Cells / Q000187:drug effects / Q000378:metabolism*; D000098682:Steroidogenic Acute Regulatory Protein
C525901:BMP15 protein, human; C525902:Bmp15 protein, mouse; D055430:Bone Morphogenetic Protein 15; C525897:GDF9 protein, human; C525898:Gdf9 protein, mouse; D055429:Growth Differentiation Factor 9; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D013256:Steroids; D000098682:Steroidogenic Acute Regulatory Protein; D015124:8-Bromo Cyclic Adenosine Monophosphate; D000249:Adenosine Monophosphate