Apoptotic dysregulation in male infertility

项目总结/摘要 在所有物种中，性发育和生育能力都依赖于细胞死亡事件。在发展中 在哺乳动物的卵巢和睾丸中，生殖细胞（精子和卵子的前体）的大量死亡发生在 胎儿消耗事件，被认为是防止过度增殖和选择最高质量的细胞。细胞死亡是 在形成雌性生殖道的结构的胚胎退化期间，也在雄性中观察到， 脑下垂体的形态发生，调节性腺激素的产生。令人惊讶的是， 细胞凋亡导致小鼠雄性特异性不育，但尚不清楚为什么会发生这种情况或细胞死亡是如何发生的。 在男性性发育过程中受到调节。我研究的目的是了解 细胞凋亡沿着下丘脑-垂体-性腺（HPG）轴在整个男性性发育，为什么 细胞凋亡的破坏导致不育。具体地说，这项建议旨在映射正常人中的凋亡敏感性。 睾丸生殖细胞，并发现不育男性生殖组织中凋亡失调的证据。在 目的1、探讨生殖细胞在发育和分化的不同阶段的凋亡易感性， 使用功能性细胞死亡预测测定和睾丸照射诱导生殖细胞死亡来确定。在 目的2、通过对胚胎发育过程中细胞凋亡的分析，探讨细胞凋亡在男性性别分化中的必要性 生殖道发育和成人HPG轴信号转导在遗传模型的细胞凋亡不足。 睾丸生殖细胞移植将用于确定生殖系与体细胞睾丸细胞的贡献 凋亡失调与男性不育的关系。这些发现将支持确定针对性治疗， 性发育障碍或影响发育中儿童的细胞毒性暴露， 成年后的生殖结果。 拟议研究金的培训计划将进一步发展分子和生物学方面的专门知识， 发展生物学方法，并解决概念和技术上的经验不足，在其他学科， 生殖科学，包括内分泌学和流行病学。它还将提供机会， 斑马鱼对小鼠作为疾病和发展的模型。这将通过继续教育来实现， 生物统计学，与共同赞助者一起进行培训，并利用跨学科科学咨询委员会监督 实验设计和数据分析。在2005年还将进行负责任的研究培训 1.哈佛公共卫生学院致力于生殖健康的多方面研究， 不孕症，将大力支持这一研究和培训计划的成像和分析设施，以及 对该领域现有教师的监督。Kristopher Sarosiek的实验室，擅长功能性 细胞凋亡的测定，将使发展一个独特的和严格的研究计划，桥梁性 发展和细胞死亡的分子生物学，以揭示男性不育的机制。

Project Summary/Abstract Across species, sexual development and fertility are dependent on cell death events. In developing ovaries and testes in mammals, massive death of germ cells (precursors of sperm and eggs) occurs during a fetal attrition event that is presumed to prevent overproliferation and select for highest quality cells. Cell death is also observed in males during embryonic regression of structures that form the female reproductive tract, and morphogenesis of the pituitary gland, which regulates gonadal sex hormone production. Surprisingly, inhibition of apoptosis results in male-specific infertility in mice, but it is not understood why this occurs or how cell death is regulated throughout male sexual development. The goal of my research is to understand regulation of apoptosis along the hypothalamic-pituitary-gonadal (HPG) axis throughout male sexual development, and why disruption of apoptosis causes infertility. Specifically, this proposal aims to map apoptotic sensitivity in normal testicular germ cells, and to find evidence of apoptotic misregulation in reproductive tissues in infertile males. In Aim 1, the apoptotic vulnerability of germ cells at different stages of development and differentiation will be determined using functional cell death-predictive assays and testicular irradiation to induce germ cell death. In Aim 2, the requirement of apoptosis in male sex differentiation will be investigated by analyzing embryonic reproductive tract development and adult HPG axis signaling in genetic models of apoptosis insufficiency. Testicular germ cell transplantation will be used to establish contribution of germline vs. somatic testicular cell apoptosis dysregulation to male infertility. These findings will support identification of targeted treatments for disorders of sexual development or cytotoxic exposures affecting developing children, which lead to poor reproductive outcomes as adults. The training plan for the proposed fellowship will further develop expertise in molecular and developmental biology approaches, and address conceptual and technical inexperience in other disciplines of reproductive science, including endocrinology and epidemiology. It will also provide the opportunity to move from zebrafish to mice as a model of disease and development. This will be achieved by continuing education in biostatistics, training with a co-sponsor, and utilizing an interdisciplinary scientific advisory committee to oversee experimental design and data analysis. Responsible conduct of research training will also be undertaken in Year 1. The Harvard School of Public Health, which is committed to the multi-faceted study of reproductive health and infertility, will strongly support this research and training plan with imaging and analytical facilities as well as oversight of established faculty in the field. The laboratory of Kristopher Sarosiek, which excels at functional assays of apoptosis, will enable development of a unique and rigorous research program that bridges sexual development and the molecular biology of cell death in order to uncover mechanisms driving male infertility.