title: Dynamic secretion during meiotic reentry integrates the function of the oocyte and cumulus cells.
abstract: The differentiation of the female gamete into a developmentally competent oocyte relies on the protected environment of the ovarian follicle. The oocyte plays a key role in establishing this microenvironment by releasing paracrine factors that control the functions of surrounding somatic cells. Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are secreted during follicle growth and play pivotal roles in this local regulation. The current view is that the function of these secreted factors declines in the periovulatory period when the oocyte reenters the meiotic cell cycle. Here, we provide evidence that oocyte reentry into meiosis is instead associated with a shift in the pattern of secretion with a new set of bioactive molecules synthesized before ovulation. Using interleukin 7 (IL7) as a prototypic secreted factor, we show that its secretion is dependent on activation of mRNA translation in synchrony with the cell cycle and that its translation is under the control of somatic cells. IL7 is part of a local feedback loop with the soma because it regulates cumulus cell replication. Similar conclusions are reached when IL7 secretion is measured in human follicular fluid during in vitro fertilization cycles. IL7 concentration in the follicular fluid correlates with the oocyte ability to reach the MII stage of maturation. These findings are consistent with the hypothesis that a new set of local factors is secreted by the oocyte during ovulation. These dynamic secretions are likely critical for promoting the final stages of maturation and oocyte developmental competence.
authors: Center for Reproductive Sciences, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA 94143.
authors: Hakan
authors: H
authors: Cakmak
authors: Center for Reproductive Sciences, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA 94143.
authors: Federica
authors: F
authors: Franciosi
authors: Center for Reproductive Sciences, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA 94143.
authors: A Musa
authors: AM
authors: Zamah
authors: Center for Reproductive Sciences, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA 94143.
authors: Marcelle I
authors: MI
authors: Cedars
authors: Center for Reproductive Sciences, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA 94143 ContiM@obgyn.ucsf.edu.
authors: Marco
authors: M
authors: Conti
mesh_terms: D049109:Cell Proliferation / Q000502:physiology; D054885:Cumulus Cells / Q000166:cytology*; D005260:Female; D015571:Follicular Fluid / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D020381:Interleukin-17 / Q000235:genetics / Q000502:physiology; D008540:Meiosis; D009865:Oocytes / Q000166:cytology*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D020381:Interleukin-17; D012333:RNA, Messenger
keywords: interleukin-7; mRNA translation; oocyte maturation; oocyte secreted factors