Primary ovarian insufficiency (POI) and polycystic ovarian syndrome are ovarian diseases causing infertility. Although there is no effective treatment for POI, therapies for polycystic ovarian syndrome include ovarian wedge resection or laser drilling to induce follicle growth. Underlying mechanisms for these disruptive procedures are unclear. Here, we explored the role of the conserved Hippo signaling pathway that serves to maintain optimal size across organs and species. We found that fragmentation of murine ovaries promoted actin polymerization and disrupted ovarian Hippo signaling, leading to increased expression of downstream growth factors, promotion of follicle growth, and the generation of mature oocytes. In addition to elucidating mechanisms underlying follicle growth elicited by ovarian damage, we further demonstrated additive follicle growth when ovarian fragmentation was combined with Akt stimulator treatments. We then extended results to treatment of infertility in POI patients via disruption of Hippo signaling by fragmenting ovaries followed by Akt stimulator treatment and autografting. We successfully promoted follicle growth, retrieved mature oocytes, and performed in vitro fertilization. Following embryo transfer, a healthy baby was delivered. The ovarian fragmentation-in vitro activation approach is not only valuable for treating infertility of POI patients but could also be useful for middle-aged infertile women, cancer patients undergoing sterilizing treatments, and other conditions of diminished ovarian reserve.

Our findings demonstrate gonadotrophins regulation of NPPC/CNP expression in mouse and human ovaries and confirm the role of CNP as a potent paracrine oocyte maturation inhibitor.

Optimal development of fertilized eggs into preimplantation embryos is essential for reproduction. Although mammalian oocytes ovulated after luteinizing hormone (LH) stimulation can be fertilized and promoted into early embryos in vitro, little is known about ovarian factors important for the conditioning of eggs for early embryo development. Because LH interacts only with ovarian somatic cells, its potential regulation of oocyte functions is presumably mediated by local paracrine factors. We performed DNA microarray analyses of ovarian transcripts and identified brainderived neurotrophic factor (BDNF) secreted by granulosa and cumulus cells as an ovarian factor stimulated by the preovulatory LH surge. Ovarian BDNF acts on TrkB receptors expressed exclusively in oocytes to enhance first polar body extrusion of oocytes and to promote the in vitro development of zygotes into preimplantation embryos. Furthermore, in vivo treatment with a Trk receptor inhibitor suppressed first polar body extrusion and the progression of zygotes into blastocysts. Thus, ovarian BDNF is important to nuclear and cytoplasmic maturation of the oocyte, which is essential for successful oocyte development into preimplantation embryos. Treatment with BDNF could condition the cultured oocytes for optimal progression into the totipotent blastocysts.early embryo development ͉ gonadotropins ͉ ovulation I n vertebrates, rupture of ovarian follicles and final maturation of oocytes occur in response to stimulation by pituitaryderived luteinizing hormones (LH) that act on the somatic granulosa and theca cells surrounding the oocyte. Shortly after stimulation by the preovulatory surge of LH, oocytes arrested at the late prophase resume meiosis characterized by germinal vesicle (nuclear envelope) breakdown (GVBD), chromosome condensation, and extrusion of the first polar body in preparation for fertilization and early embryonic development. Recent studies demonstrated that the endocrine hormone LH stimulates ovarian production of EGF-like factors from granulosa cells and insulin-like 3 from theca cells to promote GVBD (1, 2). In addition to nuclear maturation exemplified by GVBD and extrusion of the first polar body to complete the first meiotic division, oocytes also undergo cytoplasmic maturation characterized by cytoplasmic changes essential for monospermic fertilization, processing of the sperm, and preparation for development to preimplantation embryos (3, 4). Although the spermatozoon provides an essential element for embryo generation, the developmental fate of the embryo is principally dictated by the oocyte. However, few studies have explored ovarian factors that may be important for the conditioning of the oocyte in preparation for fertilization and preimplantation development.Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of proteins known to activate the highaffinity TrkB receptor and the pan-neurotrophin low-affinity receptor p75 (5). Although neurotrophins are widely expressed in the central nervous syst...

Successful implantation of the blastocyst and subsequent placental development is essential for reproduction. Expression of brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5, together with their receptor, tyrosine kinase B (TrkB), in trophectoderm cells of blastocyst suggests their potential roles in implantation and placental development. Here we demonstrated that treatment with BDNF promoted blastocyst outgrowth, but not adhesion, in vitro and increased levels of the cell invasion marker matrix metalloproteinase-9 in cultured blastocysts through the phosphatidylinositol 3-kinase pathway. After implantation, BDNF and neurotrophin-4/5 proteins as well as TrkB were expressed in trophoblast cells and placentas during different stages of pregnancy. Both TrkB and its ligands were also expressed in decidual cells. Treatment of cultured trophoblast cells with the TrkB ectodomain, or a Trk receptor inhibitor K252a, suppressed cell growth as reflected by decreased proliferation and increased apoptosis, whereas an inactive plasma membrane nonpermeable K252b was ineffective. Studies using the specific inhibitors also indicated the importance of the phosphatidylinositol 3-kinase/Akt pathway in mediating the action of TrkB ligands. In vivo studies in pregnant mice further demonstrated that treatment with K252a, but not K252b, suppressed placental development accompanied by increases in trophoblast cell apoptosis and decreases in placental labyrinth zone at midgestation. In vivo K252a treatment also decreased fetal weight at late gestational stages. Our findings suggested important autocrine/paracrine roles of the BDNF/TrkB signaling system during implantation, subsequent placental development, and fetal growth by increasing trophoblast cell growth and survival.