Service d'Histologie Embryologie, Biologie de la Reproduction, Hôpital Cochin, Assistance Publique-Hôpitaux de Paris, Université Paris Descartes, 123, Boulevard Port Royal, 75013 Paris, France.
Reproduction. 2012 Jul;144(1):53-66. doi: 10.1530/REP-12-0040. Epub 2012 May 3.
Spermatozoa undergo regulation of their functions along their lifespan through exchanges via vesicles or interactions with epithelial cells, in the epididymis, in the seminal fluid and in the female genital tract. Two different ways of oocyte membrane transfer to spermatozoa have been described: trogocytosis and exosomes. We here report an analysis of in vitro exchanges between the membranes of unfertilised oocytes and capacitated spermatozoa. We showed that optimum conditions are fulfilled when unfertilised oocytes interact with acrosome-reacted spermatozoa, a scenario mimicking the events occurring when the fertilising spermatozoon is inside the perivitelline space. Although CD9 tetraspanin is an essential molecule for fertilisation, exosome and trogocytosis transfer persists in Cd9-null oocytes in spite of their dramatic fusion failure. These exchanges are CD9 tetraspanin independent. We also confirm that mice sperm express CD9 tetraspanin and that when Cd9-null oocytes were inseminated with sperm covered with oocyte membrane materials, including CD9 tetraspanin, no rescue of the oocytes' fertilisability could be obtained. Thus, the existence of two ways of exchange between gametes during fertilisation suggests that these events could be of a physiological importance in this process.
精子在附睾、精液和女性生殖道中，通过囊泡交换或与上皮细胞相互作用，来调节其功能。已经描述了两种不同的卵母细胞膜向精子转移的方式：胞饮作用和外泌体。我们在这里报告了对未受精卵母细胞和获能精子之间体外交换的分析。我们表明，当未受精的卵母细胞与顶体反应的精子相互作用时，满足了最佳条件，这种情况模拟了受精精子在卵周隙内发生的事件。虽然 CD9 四跨膜蛋白是受精所必需的，但即使在卵母细胞严重融合失败的情况下，外泌体和胞饮作用的转移仍在继续。这些交换与 CD9 四跨膜蛋白无关。我们还证实，小鼠精子表达 CD9 四跨膜蛋白，并且当 Cd9 缺失的卵母细胞与覆盖有卵母细胞膜材料的精子受精时，包括 CD9 四跨膜蛋白，无法挽救卵母细胞的受精能力。因此，在受精过程中配子之间存在两种交换方式表明，这些事件在这个过程中可能具有生理重要性。
