The Role of the Lysosome in Aging

项目总结/摘要 溶酶体（酵母中的液泡）是酸性细胞器，其在降解微生物中的作用是众所周知的。 细胞物质通过诸如自噬的途径。除了它们在降解中的作用外， 溶酶体是细胞代谢的中心枢纽营养素如氨基酸和 离子以高水平储存在溶酶体或空泡中，营养感应途径对寿命很重要 调节如雷帕霉素靶（TOR）途径在溶酶体表面感知营养物。受损 溶酶体功能与衰老过程和年龄相关疾病的发展有关， 一段时间然而，溶酶体功能障碍如何导致生物体衰老仍不清楚。使用 酵母复制老化模型系统，我们最近揭示了这个话题，发现了一个新的代谢 溶酶体/空泡和线粒体之间的连接是衰老过程的核心。溶酶体 功能需要通过进化上保守的双极性H+-ATP酶酸化。我们发现溶酶体 酸度下降在早期复制年龄（定义为分裂数）在酵母，这种变化在 溶酶体酸性导致线粒体功能障碍和寿命限制。直接抑制溶酶体 通过V-ATP酶亚基的过度表达导致的酸化损失足以阻止线粒体 功能障碍和延长寿命，这表明溶酶体酸度是寿命的关键调节因子， 线粒体功能与这一观点相一致的是，我们还发现溶酶体酸性受葡萄糖调节 程度.热量限制（CR）增强溶酶体酸性，并且这种增强是CR诱导的细胞凋亡所必需的。 寿命延长总的来说，这些研究建立了芽殖酵母作为一个很好的模型，以了解 溶酶体在衰老中的作用，并支持我们的中心假设，溶酶体酸性是一个关键的决定因素 通过其与线粒体功能的代谢联系来延长寿命。我们以前的工作也提出了两个 我们将在本提案中解决一些重要的未解问题：溶酶体和线粒体是如何 功能连接（目的1），以及CR如何调节溶酶体/液泡的酸化以促进 寿命延长（目标2）。本提案中概述的实验将定义溶酶体的功能 这对它在衰老和疾病中的作用很重要，并确定了延长寿命的新途径， 通过增强溶酶体酸性发挥作用。溶酶体的活性是高度保守的， 物种，包括其与线粒体的代谢联系。因此，我们的长期计划是将我们的成果 从这里提出的酵母实验来确定溶酶体调节对衰老的影响， 哺乳动物系统中的疾病。

PROJECT SUMMARY/ABSTRACT Lysosomes (vacuoles in yeast) are acidic organelles that are well known for their role in degradation of cellular material through pathways such as autophagy. In addition to their role in degradation, it is also becoming clear that the lysosome is a central hub for cellular metabolism. Nutrients such as amino acids and ions are stored in the lysosome or vacuole at high levels, and nutrient-sensing pathways important for lifespan regulation such as the Target of Rapamycin (TOR) Pathway sense nutrients at the lysosomal surface. Impaired lysosomal function has been linked to the aging process and development of age-associated diseases for quite some time. However, how lysosomal dysfunction contributes to organismal aging is still unclear. Using the yeast replicative aging model system, we recently shed light on this topic by discovering a new metabolic connection between the lysosome/vacuole and mitochondria that is central to the aging process. Lysosomal function requires acidification by the evolutionarily conserved Vacuolar H+-ATPase. We found that lysosomal acidity declines at an early replicative age (defined by number of divisions) in yeast, and this change in lysosomal acidity leads to mitochondrial dysfunction and lifespan limitation. Direct suppression of lysosomal acidification loss through overexpression of V-ATPase subunits is sufficient to prevent mitochondrial dysfunction and extend lifespan, suggesting that lysosomal acidity is a critical regulator of lifespan and mitochondrial function. Consistent with this idea, we also found that lysosomal acidity is regulated by glucose levels. Calorie restriction (CR) enhances lysosomal acidity, and this enhancement is required for CR-induced lifespan extension. Collectively, these studies establish budding yeast as an excellent model to understand the role of the lysosome in aging, and support our central hypothesis that lysosomal acidity is a critical determinant of lifespan through its metabolic connection to mitochondrial function. Our previous work also raises two important unanswered questions that we will address in this proposal: how are lysosomes and mitochondria functionally connected (Aim 1), and how does CR regulate acidification of the lysosome/vacuole to promote lifespan extension (Aim 2). The experiments outlined in this proposal will define the functions of the lysosome that are important for its role in aging and disease, and identify new avenues for lifespan extension that function through enhancement of lysosomal acidity. The activity of the lysosome is highly conserved across species, including its metabolic link to the mitochondria. Thus, our long-term plan is to translate our results from the yeast experiments proposed here to determine the effects of lysosome modulation on aging and disease in mammalian systems.