Equipment purchase request for parent R01 - Mitochondrial dynamics in spermatogonial differentiation

项目摘要 线粒体越来越多地被认为是广泛的细胞和发育过程中的关键参与者， 例如细胞信号传导、干细胞自我更新和谱系定型， 代谢和氧化磷酸化。这种功能多样性在很大程度上取决于细胞类型- 特定的线粒体特征，包括线粒体数量、结构、分布和与 其他亚细胞器。这些线粒体特征是通过线粒体融合和 裂变，统称为线粒体动力学，其改变将导致改变线粒体 以细胞类型特异性方式发挥功能和活性，从而影响细胞命运决定，特别是在 发育和干细胞分化。我们发现线粒体呼吸的上调伴随着 活性氧（ROS）的增加是生后精原干细胞分化所必需的。 然而，这种升高的ROS可以增加线粒体DNA突变，这对线粒体DNA的损伤是有害的。 健康和细胞功能。干细胞如何适当地平衡线粒体活动以满足细胞的生长需要仍然是难以捉摸的。 在分化过程中竞争性地需要增加线粒体呼吸，同时维持线粒体呼吸， 健身我们的初步数据表明，在精原细胞中，线粒体融合和分裂都上调， 分化，这是维持适当的男性生育力所必需的。因此，我们建议揭示一种新的功能 精原细胞分化和生殖细胞线粒体适应性是如何被调节的机制 同时加速并适当平衡线粒体融合和分裂。为了实现这一目标，我们将 将一系列转基因小鼠模型与体外精原细胞分化相结合， 移植方法。研究结果将从根本上推进生殖医学和 和线粒体生物学，解释精原细胞分化是如何通过阶段特异性调节， 线粒体融合和裂变，从而打开了一个新的发现领域，即线粒体功能和健康 是为了支持哺乳动物发育的关键和独特的事件。另外通过 揭示线粒体动力学对生殖细胞线粒体适应性的影响，该项目将至关重要 提供了一种治疗由于线粒体功能障碍而导致的男性生育力受损的新策略。

PROJECT SUMMARY Mitochondria are increasingly recognized as key players in a wide range of cellular and developmental processes, such as cell signaling, stem cell self-renewal, and lineage commitment, beyond their canonical roles in metabolism and oxidative phosphorylation. Such functional diversity is largely determined by the cell type- specific mitochondrial features, including mitochondrial number, architecture, distribution, and interaction with other subcellular organelles. These mitochondrial features are tightly regulated via mitochondrial fusion and fission, collectively known as mitochondrial dynamics, the alteration of which will lead to changing mitochondrial functions and activities in a cell type-specific manner, and thus impacts cell fate decision, particularly during development and in stem cell differentiation. We found that upregulated mitochondrial respiration accompanied by increased reactive oxygen species (ROS) is required for postnatal spermatogonial stem cell differentiation. However, such elevated ROS can increase mitochondrial DNA mutations that are deleterious to mitochondrial fitness and cell functions. It remains elusive how stem cells properly balance mitochondrial activities to meet the competing need for increased mitochondrial respiration during differentiation while maintaining mitochondrial fitness. Our pilot data suggest that mitochondria fusion and fission are both upregulated in spermatogonial differentiation, which is essential for sustaining proper male fertility. We thus propose to reveal a novel functional mechanism of how spermatogonial differentiation and germ cell mitochondrial fitness are regulated by concurrently accelerated and properly balanced mitochondrial fusion and fission. To achieve this goal, we will integrate a series of genetically modified mouse models with in vitro spermatogonial differentiation and transplantation approaches. Study findings will fundamentally advance research in both reproductive medicine and mitochondrial biology by explaining how spermatogonial differentiation is regulated via stage-specific mitofusion and fission, thereby unlocking a new area of discovery, namely, how mitochondrial function and health are maintained so in order to support critical and unique events of mammalian development. In addition, by revealing the impacts of mitochondrial dynamics on germ cell mitochondrial fitness, this project will critically inform a novel strategy to treat impaired male fertility due to mitochondrial dysfunctions.