Synergistic roles of BMP15 and GDF9 in the development and function of the oocyte-cumulus cell complex in mice: genetic evidence for an oocyte-granulosa cell regulatory loop.
Bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9) are oocyte-specific growth factors that appear to play key roles in granulosa cell development and fertility in most mammalian species. We have evaluated the role(s) of these paracrine factors in the development and function of both the cumulus cells and oocytes by assessing cumulus expansion, oocyte maturation, fertilization, and preimplantation embryogenesis in Gdf9+/-Bmp15-/- [hereafter, double mutant (DM)] mice. We found that cumulus expansion, as well as the expression of hyaluronon synthase 2 (Has2) mRNA was impaired in DM oocyte-cumulus cell complexes. This aberrant cumulus expansion was not remedied by coculture with normal wild-type (WT) oocytes, indicating that the development and/or differentiation of cumulus cells in the DM, up to the stage of the preovulatory luteinizing hormone (LH) surge, is impaired. In addition, DM oocytes failed to enable FSH to induce cumulus expansion in WT oocytectomized (OOX) cumulus. Moreover, LH-induced oocyte meiotic resumption was significantly delayed in vivo, and this delayed resumption of meiosis was correlated with the reduced activation of mitogen-activated protein kinase (MAPK) in the cumulus cells, thus suggesting that GDF9 and BMP15 also regulate the function of cumulus cells after the preovulatory LH surge. Although spontaneous in vitro oocyte maturation occurred normally, oocyte fertilization and preimplantation embryogenesis were significantly altered in the DM, suggesting that the full complement of both GDF9 and BMP15 are essential for the development and function of oocytes. Because receptors for GDF9 and BMP15 have not yet been identified in mouse oocytes, the effects of the mutations in the Bmp15 and Gdf9 genes on oocyte development and functions must be produced indirectly by first affecting the granulosa cells and then the oocyte. Therefore, this study provides further evidence for the existence and functioning of an oocyte-granulosa cell regulatory loop.
Su
You-Qiang
YQ
The Jackson Laboratory, Bar Harbor, ME 04609, USA.
Wu
Xuemei
X
O'Brien
Marilyn J
MJ
Pendola
Frank L
FL
Denegre
James N
JN
Matzuk
Martin M
MM
Eppig
John J
JJ
D000818:Animals; D055430:Bone Morphogenetic Protein 15; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D018920:Coculture Techniques; D004789:Enzyme Activation; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D014453:Glucuronosyltransferase / Q000378:metabolism; D006107:Granulosa Cells / Q000166:cytology / Q000502:physiology*; D055429:Growth Differentiation Factor 9; D006801:Humans; D000076002:Hyaluronan Synthases; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000494:pharmacology; D008540:Meiosis; D051379:Mice; D018345:Mice, Knockout; D008845:Microinjections; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D006080:Ovarian Follicle / Q000166:cytology* / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
C525901:BMP15 protein, human; C525902:Bmp15 protein, mouse; D055430:Bone Morphogenetic Protein 15; D006063:Chorionic Gonadotropin; C525897:GDF9 protein, human; C525898:Gdf9 protein, mouse; D055429:Growth Differentiation Factor 9; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D014453:Glucuronosyltransferase; C491099:Has2 protein, mouse; D000076002:Hyaluronan Synthases; D048052:Mitogen-Activated Protein Kinase 3