MAMMALIAN PROLINE METABOLISM AND OXIDATIVE STRESS

点击翻译按钮获取中文摘要

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.