Hormonal and Paracrine Regulation of Spermatogenesis

描述（由申请人提供）：本申请的重点是人类和啮齿动物精子发生的激素和旁分泌调节。项目一（Barry Zirkin和Jonathan Jarow）探讨了为什么只有一些接受激素避孕的男性会变得无精子症的生物学机制。自然发生的种族差异对睾酮(T)为基础的避孕反应将进行研究，以解决这一生物学问题。我们将比较亚洲和高加索男性在接受激素避孕剂量T前后的睾丸内生物活性雄激素浓度，并确定hCG（人绒毛膜促性腺激素）诱导的睾丸内生物活性雄激素与精子发生之间的定量关系。这些研究将为开发有效的激素男性避孕药提供重要的新信息，并为睾酮调节男性精子发生的生理机制提供实质性的新见解。雄激素对精子发生的生物学作用是通过支持细胞中的雄激素受体介导的。项目II （Terry Brown）的主要目标是阐明驱动AR基因在支持细胞中表达的分子机制，并确定控制青春期成熟依赖和成人阶段特异性AR基因转录的特定转录因子及其顺式调控元件。Project III （William Wright）通过研究支持细胞生长因子、GDNF、FGF-2和IGF-1在体内的功能，关注精子发生的旁分泌调节，这些因子被认为参与控制干原精子的复制和分化。其核心假设是，已分化的生殖细胞通过反馈效应调节支持细胞对生长因子的表达，而生长因子的表达反过来又调节干精原细胞的分化和复制。最后，我们提出了一个试点项目（Paul Miller），这是基于我们的理解，生殖细胞DNA是受损的，可能是男性不育的一个重要因素。将开发一种快速、简单的分析方法来评估生殖细胞中氧化DNA损伤的水平，该方法使用信标适体，具有以高度特异性的方式结合配体的能力的寡核苷酸。这些生物传感器将被设计用于测量不育男性精子DNA中的氧化核苷，8-氧脱氧腺苷和8-氧脱氧鸟苷。

DESCRIPTION (provided by applicant): The focus of this application is on the hormonal and paracrine regulation of spermatogenesis in humans and rodents. Project I (Barry Zirkin and Jonathan Jarow) addresses the biological mechanisms that explain why only some men who receive hormonal contraception become azoospermic. Naturally occurring ethnic differences in the response to testosterone (T)-based contraception will be studied to address this biological issue. We will compare intratesticular concentrations of bioactive androgen in Asian and Caucasian men before and after they receive hormone-based contraceptive doses of T, and will determine the quantitative relationship between hCG [human chorionic gonadotropin]-induced intratesticular bioactive androgens and spermatogenesis. These studies should provide important new information needed to develop an effective hormone-based male contraceptive, as well as provide substantial new insight into the physiological mechanisms through which T regulates spermatogenesis in men. The biological effects of androgens on spermatogenesis are mediated via the androgen receptor (AR) in Sertoli cells. The primary objective of Project II (Terry Brown) is to elucidate the molecular mechanisms that drive expression of the AR gene in Sertoli cells and to identify the specific transcription factors and their cis-acting regulatory elements that control the pubertal maturation dependent and adult stage-specific transcription of the AR gene. Project III (William Wright) focuses on paracrine regulation of spermatogenesis by examining the in vivo function of Sertoli cell growth factors, GDNF, FGF-2 and IGF-1, which have been implicated as involved in the control of stem spermatogonial replication and differentiation. Its central hypothesis is that differentiated germ cells, via feedback effects, regulate the expression by Sertoli cells of growth factors that, in turn, regulate the differentiation and replication of stem spermatogonia. Finally, we propose a Pilot Project (Paul Miller) that is based on our understanding that germ cell DNA is subject to damage and may be an important factor in male infertility. A rapid, simple analytical method to assess the level of oxidative DNA damage in germ cells will be developed using beacon aptamers, oligonucleotides that have the ability to bind ligands in a highly specific manner. These biosensors will be designed to measure oxidized nucleosides, 8-oxodeoxyadenosine and 8-oxodeoxyguanosine, in the DNA of sperm from infertile men.