Role of microvesicles in sperm functions

精子是在睾丸中产生的。在到达卵子附近之前，它们必须穿过雄性和雌性生殖道。在比较脊椎动物物种的解剖结构时，雄性生殖道表现出很大的变异性。进行内受精的物种的一个特殊性是附睾体。这个器官由希腊语epi和Didymos组成，意思是“on”和“Tests”，这个器官是一个长长的曲折的小管，连接着睾丸和输精管，然后是射精管。在农场动物中，未解开的附睾长可达90米，精子转运可长达15天。分化的雄配子在离开睾丸后不能受精，只有在附睾期才能获得受精能力和向前运动特性。这些修饰统称为精子成熟。在这个过程中，精子与附睾腔内隔相互作用，附睾腔内隔具有一种不寻常的生化成分，这种生化成分在附睾处发生变化。附睾液顺序地与雄配子相互作用，以改变其生化成分和性质：这些改变是精子成熟所必需的。 多年来，我的研究主要集中在精子成熟过程中的生化修饰。我们对理解脊椎动物雄性生殖生理学中这一关键步骤的主要贡献之一是附睾体的特征。这些微泡被分泌到附睾腔内，并在精子修饰中发挥重要作用。我们已经证明，附睾体的生化性质和组成随着附睾体的变化而变化，它们选择性地将其某些蛋白质成分转移到成熟的精子上。我们正在进行的工作是了解附睾体的异质性、蛋白质组成和起源。我们还想了解这些小泡与成熟精子相互作用的分子机制。我们还将研究附睾体在精子生理参数中的作用。总之，我们的研究计划将为脊椎动物物种中沿着雄性生殖道处理精子的复杂过程带来新的理解。这项工作将应用于人工授精行业、与繁殖物种有关的生殖技术和濒危物种保护。

Spermatozoa are produced in the testis. They have to transit both the male and female reproductive tracts before reaching the vicinity of the egg. The male reproductive tract shows great variability when comparing the anatomy of vertebrate species. One particularity of species practicing internal fertilization is the epididymis. Formed from the Greek epi meaning «on» and didymos «testis», this organ is a long convoluted tubule linking the testis to the vas deferens followed by the ejaculatory duct. In farm animals, the unravelled epididymis can reach 90 m long and sperm transit can take as long as 15 days. The differentiated male gamete is incapable of fertilization upon leaving the testis and it is during epididymal transit that it will acquire its fertilizing ability and its forward motility properties. These modifications are collectively called sperm maturation. During this process, spermatozoa interact with the epididymal intraluminal compartment, which is characterized by an unusual biochemical composition that varies along the epididymis. The epididymal fluid interacts sequentially with the male gamete to modify its biochemical composition and properties: these modifications are necessary for sperm maturation. For many years, my studies have focussed on the biochemical modifications involved in sperm maturation. One of our major contributions to the understanding of this critical step in vertebrate male reproductive physiology is the characterization of epididymosomes. These microvesicles are secreted into the lumen of the epididymis and play major roles in sperm modifications. We have shown that the biochemical properties and composition of epididymosomes vary along the epididymis and that they selectively transfer some of their protein constituents to maturing spermatozoa. Our ongoing work is to understand the heterogeneity, the protein composition and the origin of epididymosomes. We also want to understand the molecular mechanisms governing interactions of these vesicles with the maturing spermatozoa. We will also investigate the role of epididymosomes in sperm physiological parameters. Altogether, our research program will bring new understanding to the complex process of sperm processing along the male reproductive tract in vertebrate species. This work will have application to the artificial insemination industry, to reproductive technologies concerned with breeding species and to endangered species preservation.