Defining the Translational Machinery Controlling Hypoxic Sensitivity

定义控制缺氧敏感性的转化机制

• 批准号: 10002322
• 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/10002322
• 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;没有氧气，几乎所有的动物细胞最终都会死亡。神经元尤其 对缺氧损伤敏感，如中风中的破坏所证明的。然而，各种动物和细胞 相对耐缺氧，但它们在缺氧中存活的机制知之甚少。 某些动物在严重缺氧的环境中冬眠，但以正常的行为退出冬眠， 没有神经元死亡的迹象。蛋白质翻译的强烈抑制被发现在这些 对冬眠动物的耐缺氧能力很重要。癌细胞通常相对缺氧 具有抗性并具有失调的翻译机制。综合这些观察结果的流行模型 翻译降低了能量消耗，从而增加了低氧存活率。蛋白质翻译 占能量消耗的很大一部分，细胞通过抑制翻译来应对缺氧。 然而，缺氧诱导的翻译抑制并不统一，一些缺氧保护蛋白是 在低氧条件下优先翻译。因此，流行的“能量学”模型肯定过于 简单化，也许完全不正确。本实验室对线虫C.基因的优雅 控制缺氧存活。其中许多基因编码翻译因子。与能量学一致 在模型中，这些缺氧保护性突变/RNAis减少了整体蛋白质合成和氧消耗。 然而，翻译速率和耗氧量的降低程度与水平无关 耐缺氧的能力。此外，我们发现，敲低一个翻译因子，rars-1，是保护性的， 在从缺氧中恢复时开始，此时能量保存不再重要。这些 观察表明，翻译抑制通过复杂的机制保护缺氧，而不仅仅是 降低能耗。我们建议在C中使用强大的遗传工具。优雅的人来理解 翻译机器控制缺氧存活的复杂机制。我们假设 减少mRNA翻译的生理后果取决于这种减少是如何实现的。 我们将确定生产途径，可以产生耐缺氧和研究的机制 由此它们通过以下特定目标确定低氧存活。目标1：确定途径 由此翻译机制调节缺氧损伤。我们将识别翻译中的突变 机械基因，产生耐缺氧性，也将确定基因突变，阻止缺氧。 这些翻译突变体的耐缺氧性。这些基因将被放置在通路中，它们的作用 将确定翻译上的突变。目的2：确定代谢和生理 结果翻译机制的调制与缺氧抗性。通过这些 目的是我们将发展一个更完整的理解如何翻译机制控制缺氧 生存和调节这种机制的后果。