Physiologie de la Reproduction et des Comportements (PRC) UMR7247 INRA, CNRS, Centre INRA Val de Loire, Université de Tours, IFCE, 37380, Nouzilly, France.
Physiologie de la Reproduction et des Comportements (PRC), ComUE Centre-Val de Loire, Centre INRA Val de Loire, Université de Poitiers, 37380, Nouzilly, France.
Sci Rep. 2020 Jun 30;10(1):10654. doi: 10.1038/s41598-020-67665-4.
The control of ovulation helps guarantee the success of reproduction and as such, contributes to the fitness of a species. In mammals, two types of ovulation are observed: induced and spontaneous ovulation. Recent work on camelids, that are induced ovulators, highlighted the role of a factor present in seminal plasma, beta Nerve Growth Factor (β-NGF), as the factor that triggers ovulation in a GnRH dependent manner. In the present work, we characterized alpaca β-NGF (aβ-NGF) and its 3D structure and compared it with human recombinant β-NGF (hβ-NGF). We showed that the β-NGF enriched fraction of alpaca semen and the human recombinant protein, both stimulated spontaneous electrical activity of primary GnRH neurons derived from mouse embryonic olfactory placodes. This effect was dose-dependent and mediated by p75 receptor signaling. P75 receptors were found expressed in vitro by olfactory ensheathing cells (OEC) in close association with GnRH neurons and in vivo by tanycytes in close vicinity to GnRH fibers in adult mouse. Altogether, these results suggested that β-NGF induced ovulation through an increase in GnRH secretion provoked by a glial dependent P75 mediated mechanism.
排卵控制有助于保证生殖的成功，从而有助于物种的适应性。在哺乳动物中，观察到两种类型的排卵：诱导排卵和自发排卵。最近对诱导排卵的骆驼科动物的研究强调了存在于精液中的一种因子，即β神经生长因子（β-NGF），作为以 GnRH 依赖方式触发排卵的因子的作用。在本工作中，我们对羊驼β-NGF（aβ-NGF）及其 3D 结构进行了表征，并将其与重组人β-NGF（hβ-NGF）进行了比较。我们表明，羊驼精液中富含β-NGF 的部分和重组人蛋白均刺激了源自小鼠胚胎嗅基板的原代 GnRH 神经元的自发电活动。这种作用呈剂量依赖性，并通过 p75 受体信号转导介导。在体外，p75 受体被嗅鞘细胞（OEC）表达，与 GnRH 神经元密切相关，在体内，在成年小鼠中，p75 受体被 GnRH 纤维附近的室管膜细胞表达。总之，这些结果表明，β-NGF 通过依赖于神经胶质的 p75 介导的机制引起的 GnRH 分泌增加来诱导排卵。
