Aging and Ovarian Stem Cell Niche Dysfunction

项目摘要 干细胞生物学中最令人兴奋的领域之一与干细胞功能障碍 在与衰老相关的器官功能恶化中发挥核心作用。最近的研究表明，卵原细胞（卵母细胞- 产生）干细胞（OSC）存在于成年哺乳动物卵巢中。OSC的存在提出了以下可能性： 卵巢老化，标志着含卵母细胞卵泡的损失和耗尽，可能同样涉及 干细胞功能逐渐丧失。因此，现在重要的是确定OSCs的生理作用， 卵巢功能和衰老。我的长期目标是确定衰老过程如何对OSC产生负面影响 功能，因此使用OSCs作为模型，以提供对基于干细胞的机制的深入了解， 衰老具体而言，我建议使用我们开发的新型自杀基因转基因（sg-Tg）小鼠模型 在过去的三年里研究这个。这些小鼠模型的独特之处在于， 可以使用自杀基因技术选择性地靶向和消融细胞。在我们的初步数据中，我们显示 这些OSC分化途径的选择性破坏导致遗传上定义的可逆性的 原始卵泡这些发现支持了哺乳动物卵巢卵母细胞储备的维持 在成年期，包括从OSCs主动输入新的卵母细胞。这些数据也为 未来对卵巢生物学和疾病发病机制的研究具有前所未有的可能性，包括 了解女性生殖老化对OSC对卵巢功能的贡献。的 该建议的具体目的是：1）使用新的方法建立OSCs在卵巢衰老中的生理作用， 我们已经开发的sg-Tg小鼠，其中分化中的OSC子细胞可以被选择性地消融; 2） 评价胶质细胞源性神经营养因子（GDNF）和成纤维细胞生长因子（FGF 9）作为可能的OSC 分别刺激OSC增殖和抑制OSC减数分裂分化的生态位因子; 3） 在OSC有丝分裂活动增加期间表征OSC小生境，并检查 血管内皮细胞的生态位功能;和，4）开发改善的OSC培养条件，通过使用卵巢 体细胞作为饲养细胞，以再现离体OSC-生态位相互作用，并检查衰老对 OSC活动。最终，这些信息可能会用于开发新的和有针对性的治疗方法， 通过在需要时刺激OSC活性来增加卵母细胞储备，从而改善卵巢功能 - 如卵巢早衰患者、高龄产妇（推迟年龄- 相关的卵巢衰竭和绝经）或女性癌症患者（以挽救其卵巢功能， 抗癌治疗后的生育能力）-所有这些条件都代表着增加

Project Summary One of the most exciting areas of stem cell biology relates to the possibility that stem cell dysfunction plays central role in aging-related deterioration of organ function. Recent studies suggest that oogonial (oocyte- producing) stem cells (OSCs) exist in the adult mammalian ovary. Existence of OSCs raises the possibility that ovarian aging, marked by loss and exhaustion of oocyte-containing follicles, may similarly involve a progressive loss of stem cell function. Thus, it is now important to establish the physiological roles of OSCs in ovarian function and aging. My long-term goal is to determine how the aging process negatively affects OSC function, and thus use OSCs as a model to provide insight into stem cell-based mechanisms for organismal aging. Specifically, I propose to use novel suicide gene transgenic (sg-Tg) mouse models we have developed over the past three years to study this. These mouse models are unique in that differentiating OSC daughter cells can be selectively targeted and ablated using suicide gene technology. In our preliminary data, we show that selective disruption of these OSC differentiation pathways results in a genetically defined reversible loss of primordial follicles. These findings support that the maintenance of the oocyte reserve in mammalian ovaries during adulthood involves active input of new oocytes from OSCs. These data also lay a solid foundation for future studies of ovarian biology and disease pathogenesis with unprecedented possibilities, including an understanding of female reproductive aging that accounts for OSC contribution to ovarian function. The specific aims of this proposal are to: 1) establish the physiological roles of OSCs in ovarian aging using novel sg-Tg mice we have developed, in which differentiating OSC daughter cells can be selectively ablated; 2) evaluate glial cell-derived neurotrophic factor (GDNF) and fibroblast growth factor (FGF9) as possible OSC niche factors in stimulating OSC proliferation and suppressing OSC meiotic differentiation, respectively; 3) characterize OSC niches during periods of increased OSC mitotic activity and examine the participation of vascular endothelial cells in niche function; and, 4) develop improved OSC culture conditions by using ovarian somatic cells as feeder cells to recapitulate OSC-niche interaction ex vivo and examine the impact of aging on OSC activity. Ultimately, this information might be used to develop novel and targeted therapeutics that rescue ovarian function through increasing the oocyte reserve by stimulating OSC activity when it would be desirable - such as in patients with premature ovarian failure, in women of advanced maternal age (to postpone age- related ovarian failure and menopause) or in female cancer patients (to rescue their ovarian function and fertility after anti-cancer treatments) - all of these conditions represent increasing