Eppig J J, Chesnel F, Hirao Y, O'Brien M J, Pendola F L, Watanabe S, Wigglesworth K
The Jackson Laboratory, Bar Harbor, ME 04609, USA.
Hum Reprod. 1997 Nov;12(11 Suppl):127-32.
Interaction between oocytes and granulosa cells is complex and involves both gap junctions and paracrine signalling factors. Oocyte development in antral follicles is highly dependent on communication with cumulus cells, a subset of granulosa cells that is intimately associated with oocytes. Cumulus cells express characteristics distinct from the mural granulosa cells of preovulatory follicles. The thesis of this paper is that, without the influence of oocytes, the pathway of granulosa cell differentiation in antral follicles leads to the establishment of the mural granulosa cell phenotype. Oocytes in antral follicles abrogate that pathway of granulosa cell differentiation and promote the development of the cumulus cell phenotype. Oocytes may do this in order to control their own microenvironment by regulating differentiation of the supporting cells that are in direct communication with them. Possibly, some aspects of the mural granulosa cell phenotype are antagonistic to, or insufficient for, supporting the final stages of oocyte development. We present evidence that oocytes control their environment by suppressing differentiation of the mural granulosa cell phenotype and promoting differentiation of the cumulus cell phenotype. They achieve this suppression via the secretion of labile paracrine signalling factors. Errors in this regulatory mechanism, whether instigated by defects in the production of oocyte-derived ligands or granulosa cell responses to them, may result in the production of oocytes unable to undergo embryo development or that undergo abnormal follicular development.
卵母细胞与颗粒细胞之间的相互作用十分复杂，涉及缝隙连接和旁分泌信号因子。窦状卵泡中的卵母细胞发育高度依赖于与卵丘细胞的通讯，卵丘细胞是颗粒细胞的一个亚群，与卵母细胞密切相关。卵丘细胞表现出与排卵前卵泡的壁颗粒细胞不同的特征。本文的论点是，在没有卵母细胞影响的情况下，窦状卵泡中颗粒细胞的分化途径会导致壁颗粒细胞表型的建立。窦状卵泡中的卵母细胞消除了颗粒细胞的这种分化途径，并促进卵丘细胞表型的发育。卵母细胞可能通过调节与其直接通讯的支持细胞的分化来控制自身的微环境。壁颗粒细胞表型的某些方面可能对卵母细胞发育的最后阶段具有拮抗作用或不足以支持该阶段。我们提供的证据表明，卵母细胞通过抑制壁颗粒细胞表型的分化和促进卵丘细胞表型的分化来控制其环境。它们通过分泌不稳定的旁分泌信号因子来实现这种抑制作用。这种调节机制中的错误，无论是由卵母细胞衍生配体产生缺陷还是颗粒细胞对其反应缺陷引发，都可能导致产生无法进行胚胎发育或卵泡发育异常的卵母细胞。
