Metabolic regulation by p66Shc determines stem cell fate and neuronal survival

p66Shc 的代谢调节决定干细胞命运和神经元存活

• 批准号: RGPIN-2019-06893
• 负责人: Cumming, Robert
• 金额: $ 2.62万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=745666
• 关键词: Metabolic; regulation; p66Shc; determines; stem

Mammalian cells used specialized organelles called mitochondria to break down nutrients and generate high levels of ATP, a chemical form of energy, in a process dependent on the presence of oxygen. However, oxygen radicals are potentially harmful by-products that arise during mitochondrial metabolism. During the aging process, mammals frequently exhibit increased production of oxygen radicals, or the decreased ability to detoxify them, particularly in specialized brain cells called neurons. Due to their high metabolic state, neurons are particularly vulnerable to mitochondrial generated oxygen radicals. Thus, neurons in the brain must be able to mount a sufficient antioxidant defense to maintain survival throughout one's lifespan. Alternatively, to replenish neuron cell death, adult stem cells can give rise to functional neurons, in a process called differentiation. The precise regulation of stem cell differentiation, and antioxidant defense in neurons, is critical to maintain brain function throughout life. Recent studies have shown that a unique signaling protein called p66Shc can move from the cytosol, the main fluid containing portion of a cell, into mitochondria following exposure to certain forms of stress. Once in the mitochondria, p66Shc triggers increased oxygen radical formation that can then promote a variety of outcomes, including neuronal differentiation or cell death. However, the precise mechanism by which p66Shc controls these cellular processes is poorly understood. Recent studies in my lab have revealed that p66Shc can act as a "switch" which turns off glycolysis, a form of metabolism that does not generate oxygen radicals, while turning on mitochondrial metabolism. In addition, p66Shc also suppresses the activation of a key protein called Nrf2 that is required for expression of antioxidant genes. Using both cultured mouse embryonic stem cells and neuron-like cells, we will explore the hypothesis that p66Shc induced mitochondrial metabolism and oxygen radical production affects the ability of stem cells to differentiate, and form neurons to mount an appropriate antioxidant response. In addition, we will identify the types of specific proteins that become oxidatively modified in response to p66Shc induced oxygen radical production. As a long-term goal, we will also generate mice in which the p66Shc gene is deleted in either adult brain stem cells or neurons. The results of the proposed study will provide novel insight into the molecular mechanisms controlling stem cell differentiation and how neurons respond to stress; events critical for optimal brain function throughout life.

哺乳动物细胞使用称为线粒体的专门细胞器来分解营养物质并产生高水平的ATP，ATP是一种化学形式的能量，这一过程依赖于氧气的存在。然而，氧自由基是线粒体代谢过程中产生的潜在有害副产物。在衰老过程中，哺乳动物经常表现出氧自由基产生增加，或解毒能力下降，特别是在称为神经元的专门脑细胞中。由于它们的高代谢状态，神经元特别容易受到线粒体产生的氧自由基的影响。因此，大脑中的神经元必须能够建立足够的抗氧化防御，以维持整个生命周期的生存。或者，为了补充神经元细胞死亡，成体干细胞可以在称为分化的过程中产生功能性神经元。干细胞分化的精确调节，以及神经元中的抗氧化防御，对于维持整个生命中的大脑功能至关重要。最近的研究表明，一种名为p66 Shc的独特信号蛋白可以在暴露于某些形式的压力后从细胞质（细胞的主要流体）进入线粒体。一旦进入线粒体，p66 Shc触发氧自由基形成增加，然后可以促进各种结果，包括神经元分化或细胞死亡。然而，p66 Shc控制这些细胞过程的确切机制知之甚少。我实验室最近的研究表明，p66 Shc可以作为一个“开关”，关闭糖酵解，一种不产生氧自由基的代谢形式，同时打开线粒体代谢。此外，p66 Shc还抑制了一种称为Nrf 2的关键蛋白的激活，该蛋白是抗氧化基因表达所必需的。 使用培养的小鼠胚胎干细胞和神经元样细胞，我们将探讨这一假设，即p66 Shc诱导的线粒体代谢和氧自由基的产生影响干细胞的分化能力，并形成神经元安装适当的抗氧化反应。此外，我们将确定的类型的特定蛋白质，成为氧化修饰的p66 Shc诱导的氧自由基的生产。作为一个长期目标，我们还将产生p66 Shc基因在成体脑干细胞或神经元中缺失的小鼠。这项研究的结果将为控制干细胞分化的分子机制以及神经元如何应对压力提供新的见解;这些事件对整个生命中的最佳大脑功能至关重要。