MAMMALIAN PROLINE METABOLISM AND OXIDATIVE STRESS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 这项研究的总体目标是提供一个分子理解如何影响与氧化还原相关的生理过程的Pro和Pro代谢。脯氨酸代谢被认为对生物能量学、细胞氧化还原控制、细胞凋亡、癌症和精神分裂症有重要影响。在P53介导的细胞凋亡过程中，线粒体中的Pro脱氢酶(PROH)通过产生依赖于Pro的活性氧物种(ROS)在肿瘤抑制中发挥重要作用。一个不太为人所熟知的作用是它具有抵御氧化应激的潜力，这一特性直到最近才在哺乳动物系统中被相对探索。这个项目的中心假设是，在应激期间，Pro在哺乳动物细胞中作为广泛的抗氧化剂，通过清除ROS和维持氧化还原平衡来发挥作用。虽然有强有力的证据表明，Pro在细胞凋亡途径中具有重要的作用，但Pro清除ROS和影响氧化还原动态平衡的能力尚未建立。这项建议的主要目的是确定在不同类型的人类细胞中，脯氨酸是否对ROS介导的应激具有保护作用，并阐明Pro调节细胞内氧化还原环境的机制。 这项研究的具体目的是： 1.评价内源性脯氨酸对氧化应激的保护作用。在多种氧化应激条件下，通过改变多种哺乳动物细胞中的脯氨酸分解代谢酶和合成代谢酶的表达，来测试脯氨酸提供应激保护的能力。还将检测氧化应激下细胞中的脯氨酸代谢基因的表达谱，以确定在哪些生理条件下，脯氨酸起到抗氧化剂的作用。 2.阐明了脯氨酸清除ROS的机制。在氧化应激条件下，将进行Pro的代谢示踪研究，以探索Pro清除ROS的机制。抗氧化酶的活性和氧化还原条件(即NADP/NADPH和谷胱甘肽水平)也将被测量，并与不同的脯氨酸水平和胁迫条件相关联。 这项工作将提供一个生化理解如何影响氧化还原相关的生理过程中的癌症和神经疾病，并增加我们对P53相关的肿瘤抑制机制的了解。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall goal of this study is to provide a molecular understanding of how proline and proline metabolism impact redox-linked physiological processes. Proline metabolism is recognized as having an important impact on bioenergetics, cellular redox control, apoptosis, cancer and schizophrenia. The mitochondrion enzyme proline dehydrogenase (PRODH) plays an important role in tumor suppression by generating proline-dependent reactive oxygen species (ROS) during p53-mediated apoptosis. A less well-recognized role of proline is its potential to protect against oxidative stress, a property that has been relatively unexplored in mammalian systems until only recently. The central hypothesis of this project is that proline functions as broad-based antioxidant in mammalian cells during stress by scavenging ROS and maintaining redox homeostasis. While there is strong evidence that proline has an important role in cellular apoptotic pathways, the ability of proline to scavenge ROS and impact redox homeostasis has not been established. The main objectives of this proposal are to determine whether proline protects against ROS mediated stress in different human cell types and to elucidate the mechanisms whereby proline modulates the intracellular redox environment. The specific aims of this study are: 1. Evaluate the protective ability of endogenous proline against oxidative stress. The ability of proline to confer stress protection will be tested by altering the expression of proline catabolic and anabolic enzymes in a variety of mammalian cells under multiple oxidative stress conditions. Expression profiles of proline metabolic genes in cells under oxidative stress will also be examined to identify physiological conditions in which proline functions as an antioxidant. 2. Elucidate the mechanism by which proline scavenges ROS. Metabolic tracer studies of proline under oxidative stress conditions will be performed to probe the mechanism by which proline scavenges ROS. The activity of antioxidant enzymes and the redox conditions (i.e. NADP/NADPH and glutathione levels) will also be measured and correlated with different proline levels and stress conditions. This work will provide a biochemical understanding of how proline and proline metabolism impact redox linked physiological processes underlying cancer and neurological disorders and increase our knowledge of p53-linked tumor suppression mechanisms.