Growth differentiation factor 9 is antiapoptotic during follicular development from preantral to early antral stage.
Ovarian follicular atresia represents a selection process that ensures the release of only healthy and viable oocytes during ovulation. The transition from preantral to early antral stage is the penultimate stage of development in terms of gonadotropin dependence and follicle destiny (survival/growth vs. atresia). We have examined whether and how oocyte-derived growth differentiation factor 9 (GDF-9) and FSH regulate follicular development and atresia during the preantral to early antral transition, by a novel combination of in vitro gene manipulation (i.e. intraoocyte injection of GDF-9 antisense oligos) and preantral follicle culture. Injection of GDF-9 antisense suppressed basal and FSH-induced preantral follicle growth in vitro, whereas addition of GDF-9 enhanced basal and FSH-induced follicular development. GDF-9 antisense activated caspase-3 and induced apoptosis in cultured preantral follicles, a response attenuated by exogenous GDF-9. GDF-9 increased phospho-Akt content in granulosa cells of early antral follicles. Although granulosa cell apoptosis induced by ceramide was attenuated by the presence of GDF-9, this protective effect of GDF-9 was prevented by the phosphatidylinositol 3-kinase inhibitor LY294002 and a dominant negative form of Akt. Injection of GDF-9 antisense decreased FSH receptor mRNA levels in cultured follicles, a response preventable by the presence of exogenous GDF-9. The data suggest that GDF-9 is antiapoptotic in preantral follicles and protects granulosa cells from undergoing apoptosis via activation of the phosphatidylinositol 3-kinase/Akt pathway. An adequate level of GDF-9 is required for follicular FSH receptor mRNA expression. GDF-9 promotes follicular survival and growth during the preantral to early antral transition by suppressing granulosa cell apoptosis and follicular atresia.
Orisaka
Makoto
M
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, University of Ottawa, Ottawa Health Research Institute, The Ottawa Hospital (Civic Campus), Ottawa, Ontario, Canada K1Y 4E9.
Orisaka
Sanae
S
Jiang
Jin-Yi
JY
Craig
Jesse
J
Wang
Yifang
Y
Kotsuji
Fumikazu
F
Tsang
Benjamin K
BK
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D055430:Bone Morphogenetic Protein 15; D053148:Caspase 3 / Q000378:metabolism; D002867:Chromones / Q000494:pharmacology; D017931:DNA Primers; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D005496:Follicular Atresia / Q000502:physiology*; D006107:Granulosa Cells / Q000378:metabolism; D055429:Growth Differentiation Factor 9; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D009025:Morpholines / Q000494:pharmacology; D016376:Oligonucleotides, Antisense / Q000378:metabolism / Q000494:pharmacology; D006080:Ovarian Follicle / Q000187:drug effects / Q000254:growth & development*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction
C525904:Bmp15 protein, rat; D055430:Bone Morphogenetic Protein 15; D002867:Chromones; D017931:DNA Primers; C525899:Gdf9 protein, rat; D055429:Growth Differentiation Factor 9; D036341:Intercellular Signaling Peptides and Proteins; D009025:Morpholines; D016376:Oligonucleotides, Antisense; D000081082:Phosphoinositide-3 Kinase Inhibitors; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D005640:Follicle Stimulating Hormone; C505410:Casp3 protein, rat; D053148:Caspase 3