How do spermatozoa become competent for fertilization: study on membrane and intracellular events

精子是高度分化的细胞，其唯一的作用是使卵子受精以产生新的个体。 为了达到这个目的，精子由两个不同的部分连接在一起组成：头部包含一半的父系遗传物质，鞭毛是将遗传物质与卵子接触所需的移动器官。 虽然在睾丸出口处精子的结构是完整的，但在附睾运输过程中，精子细胞获得了移动和与排卵的卵子相互作用的能力。然而，它们在射精前保持不动，此时它们与精囊和前列腺的分泌物混合。 这个过程被称为运动激活。 一旦进入雌性生殖道，精子与细胞和分泌物相互作用，并在称为获能的过程中完全具有受精能力，并且与精子运动性的超活化有关，这是更有力的，增加细胞速度和强度以促进精子通过卵子相关的载体，例如卵丘，一种含有连接在一起的卵丘细胞的高度粘稠的富含蛋白多糖的流体，透明质膜，一种由卵母细胞生长产生的相对较厚的细胞外基质。 尽管涉及影响不同细胞内信号转导途径调节环AMP-、Ca 2 +-、pH-和蛋白酪氨酸磷酸化介导事件的试剂，但调节获能和精子/卵子相互作用过程的机制尚未完全了解。我的研究项目致力于进一步研究精子获得精子可再生性过程中的精子细胞内生化事件，并更好地表征精子与卵子相互作用中涉及的介质，这些介质将导致受精和遗传独特个体的早期发育。这项研究计划无疑将对濒危物种遇到的生育问题产生影响，在依赖成功繁殖的农业行业（乳制品，肉类）中，最终在人类中，生活方式和环境对男性生育力有很大影响。

Spermatozoa are highly differentiated cells which only role is to fertilize the egg in order to produce a new individual. To achieve its goal, spermatozoa are made of two distinct compartments linked together: the head which contains half of the paternal genetic content, and the flagellum, which is the mobility organ required to bring the genetic content in contact with the egg. Although structurally complete at the exit of the testis, sperm cells acquire the ability to move and to interact with the ovulated egg during the epididymal transit. However, they but remain in immotile until ejaculation, when they are mixed with the secretions from the seminal vesicles and the prostate. This process is called motility activation. Once in the female reproductive tract, sperm interacts with cells and secretion, and become fully fertilization competent in a process called capacitation and is associated with the hyperactivation of sperm motility, which is more vigorous, increasing cell velocity and strength to facilitate sperm passage through egg associated vestments such as the cumulus, a highly viscous proteoglycan-rich fluid containing cumulus cells linked together, and the zona pellucida, a relatively thick extracellular matrix produced by the growing oocyte. The mechanisms regulating the processes of capacitation and sperm/egg interactions are not fully understood although agents affecting different intracellular signal transduction pathways regulating cyclic AMP-, Ca2+-, pH-, and protein tyrosine phosphorylation-mediated events are involved. My research program is devoted to further investigate sperm intracellular biochemical events during the acquisition of sperm fertilizing ability and to better characterize the mediators involved in the sperm interactions with the egg that will result in fertilization and early development of a genetically unique individual. This research program will undoubtedly have impact on fertility problems encountered in endangered species, in agricultural industries (dairy, meat) that depend on successful reproduction and, ultimately in humans where lifestyle and environment have strong impacts on male fertility.