Defining the Translational Machinery Controlling Hypoxic Sensitivity

定义控制缺氧敏感性的转化机制

• 批准号: 10246395
• 负责人: C. Michael Crowder
• 金额: $ 38.61万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-15 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10246395
• 关键词: Affect; Animals; Behavior; Biogenesis; Caenorhabditis elegans; Cell Hypoxia; Cell physiology; Cells; Complex; Consumption; Environment; Genes; Genetic; Genetic Screening; Genetic Translation; Hibernation; High temperature of physical object; Hypoxia; Injury; Measures; Metabolic; Metabolism; Modeling; Mutation; Nematoda; Neurons; Output; Oxygen; Oxygen Consumption; Pathway interactions; Phenotype; Physiological; Physiology; Process; Protein Biosynthesis; Proteins; Proteome; Reagent; Recovery; Research; Resistance; Ribosomes; Role; Stress; Stroke; Suppressor Mutations; Theoretical model; Translating; Translations; Work; cancer cell; causal variant; knock-down; mutant; mutation screening; neuron loss; preservation; resistance mechanism; tool; translation factor; virtual

Animal cells need oxygen for survival; without it virtually all animal cells eventually die. Neurons are particularly sensitive to hypoxic injury as evidenced by the devastation in stroke. However, a variety of animals and cells are relatively hypoxia resistant, but the mechanisms whereby they survive hypoxia are poorly understood. Certain animals hibernate in severe hypoxic environments yet exit from hibernation with normal behavior and physiology and no evidence of neuronal death. Strong suppression of protein translation is found in these hibernating animals and is important to their hypoxia resistance. Cancer cells are often relatively hypoxia resistant and have dysregulated translation machinery. The prevailing model to synthesize these observations is that translation lowers energy consumption and thereby increases hypoxic survival. Protein translation accounts for a large fraction of energy consumption, and cells respond to hypoxia by suppressing translation. However, hypoxia-induced translational suppression is not uniform, and some hypoxia-protective proteins are preferentially translated under hypoxic conditions. Thus, the prevailing “energetics” model is certainly overly simplistic and perhaps entirely incorrect. Our lab has performed screens in the nematode C. elegans for genes controlling hypoxic survival. Many of these genes encode translation factors. Consistent with energetics models, these hypoxia protective mutations/RNAis reduce overall protein synthesis and oxygen consumption. However, the degree of reduction in translation rate and oxygen consumption does not correlate with the level of hypoxia resistance. Further, we showed that knockdown of one translation factor, rars-1, is protective when initiated during recovery from hypoxia when energy preservation should no longer be important. These observations suggest that translational suppression protects from hypoxia by complex mechanisms, not simply lowering energy consumption. We propose using the powerful genetic tools in C. elegans to understand the complex mechanism whereby the translation machinery controls hypoxic survival. We hypothesize that the physiological consequences of reducing mRNA translation vary depending on how this reduction is achieved. We will identify productive pathways that can produce resistance to hypoxia and study the mechanisms whereby they determine hypoxic survival through the following specific aims. Aim1: Define pathways whereby translation machinery regulates hypoxic injury. We will identify mutations in translation machinery genes that produce hypoxia resistance and will also identify mutations in genes that block the hypoxia resistance in these translation mutants. These genes will be placed in pathways and the effect of their mutations on translation will be determined. Aim 2: Determine the metabolic and physiological consequences of translation machinery modulation associated with hypoxia resistance. Through these aims we will develop a more complete understanding of how the translation machinery controls hypoxic survival and the consequences of the modulation of this machinery.

动物细胞需要氧气才能生存。几乎没有它，所有动物细胞最终都会死亡。神经元特别是 对中风的破坏证明了对低氧损伤的敏感。但是，各种动物和细胞 相对耐药性相对较低，但是它们在缺氧中存活的机制知之甚少。 某些动物在严重的低氧环境中冬眠，但以正常行为和 生理学，没有神经元死亡的证据。在这些中发现了强烈抑制蛋白质翻译 冬眠动物，对于它们的缺氧性耐药性很重要。癌细胞通常是相对缺氧的 耐药性和失调的翻译机械。综合这些观察结果的流行模型 这是翻译降低能源消耗，从而增加缺氧的生存率。蛋白质翻译 占能源消耗的很大一部分，细胞通过抑制翻译来应对缺氧。 然而，缺氧引起的翻译抑制并不统一，一些缺氧保护蛋白是 优先在低氧条件下翻译。那就是普遍的“能量”模型当然是过于过的 简单，也许是完全不正确的。我们的实验室已经在线虫秀丽隐杆线虫中进行了筛选。 控制低氧生存。这些基因中的许多编码翻译因子。与能量学一致 模型，这些缺氧保护突变/RNAIS减少了总体蛋白质合成和氧气消耗。 但是，翻译速率和耗氧量的降低程度与水平无关 缺氧性耐药性。此外，我们表明，当一个翻译因子RARS-1的敲低时，会受到保护 当能量制备不再重要时，在从缺氧中恢复期间启动。这些 观察结果表明，翻译抑制可以通过复杂机制来保护缺氧，而不仅仅是 降低能耗。我们建议在秀丽隐杆线虫中使用强大的遗传工具来了解 复杂机制，转化机制控制缺氧生存。我们假设 减少mRNA翻译的生理后果取决于如何实现这种减少。 我们将确定可以产生对缺氧性抗性并研究机制的生产途径 他们通过以下特定目的确定低氧生存。 AIM1：定义途径 因此，翻译机械调节低氧损伤。我们将确定翻译中的突变 产生缺氧性低的机械基因，还将识别阻断基因的突变 这些翻译突变体中的低氧性。这些基因将被放置在途径中及其效果 将确定翻译的突变。目标2：确定代谢和生理 与缺氧抗性相关的翻译机制调制的后果。通过这些 目的我们将对翻译机械如何控制低氧的方式有更完整的了解 生存和该机械调制的后果。