Collaborative Research: Regulation of the transition from primary to secondary ovarian follicle development by androgens in a teleost model

生产可受精的脊椎动物卵子是一个复杂的过程，在这个过程中，一个相对较小且相对不专门的细胞，即卵母细胞，被提供了各种母体材料，以支持受精和早期胚胎发育。因此，“卵子质量”的许多方面都相对较早地被确定下来。“卵子质量”一词用于描述一个可以连续受精并产生可存活后代的卵子。该项目将使用非哺乳动物脊椎动物模型的卵巢来确定荷尔蒙如何调节早期卵母细胞的生长。由于脊椎动物卵子发育的保守性，这项研究将提高包括人类和农业上重要动物在内的脊椎动物卵子发育的基本知识，并可能导致开发改进的方法，以克服养护和商业水产养殖中圈养鱼类的生殖障碍。该项目将把研究和教育结合起来，从西语裔服务机构加州州立大学富勒顿分校招收本科生和研究生，与华盛顿大学的不同科学家团队以及一家联邦机构的研究人员合作。其目标是培训下一代科学家如何应用分子工具、生物信息学和组织学解决生物学问题，同时深入了解动物生理学、内分泌学和生殖。这项研究将通过已建立的伙伴关系向科学界和公众展示，为受训者提供服务学习体验。雌性硬骨鱼繁殖的基本生理学，特别是在卵子发生的后期阶段(如卵黄发生、成熟、排卵)相当了解。相比之下，人们对进入青春期的过程知之甚少。在卵巢中，当初级生长的卵泡(包含发育中的卵母细胞)被招募到二次生长时，就会发生这种情况。使用鲑鱼卵巢外植体的体外模型，研究人员已经证明，11-酮睾酮(11kt)，一种硬骨特有的芳香化雄激素，促进初级和早期次级卵泡的发育，与通过RNA-Seq识别数百至数千个基因的变化相关，取决于阶段。这些变化与激素信号通路的改变、组织重塑以及向早期次级卵泡表型的进展是一致的。该项目将通过利用蛋白质组学、定量类固醇生化分析和同源重组促性腺激素的可用性来进一步探索雄激素对早期卵巢卵泡至关重要的假设，以：表征青春期开始的雌性鳕鱼体内存在的主要内源性雄激素；表征雄激素受体；利用尖端蛋白质组学记录卵巢卵泡蛋白与发育相关的变化；以及探索促性腺激素在调控先天卵巢卵泡发育中的潜在作用。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Production of a fertilizable vertebrate egg is a complex process in which a small and relatively unspecialized cell, the oocyte, is provisioned with a variety of maternal materials that support fertilization and early embryonic development. Thus, many aspects of "egg quality", the term used to describe an egg that can be successively fertilized and lead to a viable offspring, are determined relatively early. The project will use ovaries from a non-mammalian vertebrate model to determine how early oocyte growth is regulated by hormones. Because of the conserved nature of egg development in vertebrates, the research will improve fundamental knowledge of egg development in vertebrates, including humans and agriculturally important animals, and may lead to the development of improved methods to overcome reproductive dysfunction of captive-reared fish in conservation and commercial aquaculture. The project will integrate research and education by recruiting undergraduate and graduate students from California State University Fullerton, a Hispanic Serving Institution, to work with a diverse group of scientists from the University of Washington, and with researchers from a federal agency. The goal is to train the next generation of scientists how to apply molecular tools, bioinformatics, and histology to biological questions while gaining an in-depth understanding of animal physiology, endocrinology, and reproduction. The research will be presented to the scientific community and to the public via established partnerships to provide trainees with service-learning experience.The basic physiology of female teleost reproduction, particularly during the later stages of oogenesis (e.g., vitellogenesis, maturation, ovulation) is fairly well understood. By contrast, comparatively little is known about the transition into puberty. In the ovary, this occurs when the primary growth ovarian follicles (containing developing oocytes) are recruited into secondary growth. Using a well-characterized in vitro model using coho salmon ovarian explants, the investigators have shown that 11-ketotestosterone (11KT), a teleost-specific aromatizable androgen, promotes the development of primary and early secondary ovarian follicles, associated with identification via RNA-Seq of altered mRNA levels of hundreds to thousands of genes, depending on stage. These changes are consistent with altered hormonal signaling pathways, tissue remodeling, and the progression to an early secondary ovarian follicle phenotype. The project will further explore the hypothesis that androgens are essential for early ovarian follicle by exploiting advances in proteomics, quantitative steroid biochemical analyses and the availability of homologous recombinant gonadotropins to: characterize the major endogenous androgens present in the female coho salmon during the onset of puberty; characterize androgen receptors; document the development-related changes in ovarian follicle proteins using cutting-edge proteomics; and explore the potential roles of gonadotropins in regulating previtellogenic ovarian follicle development.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.