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；没有它，几乎所有动物细胞最终都会死亡。神经元特别 对缺氧损伤敏感，如中风造成的破坏所证明的那样。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尚不清楚。 某些动物在严重缺氧的环境中冬眠，但以正常的行为和状态退出冬眠。 生理学，没有神经元死亡的证据。在这些中发现了对蛋白质翻译的强烈抑制 冬眠动物，对于它们的耐缺氧能力很重要。癌细胞往往处于相对缺氧的状态 抵抗并且翻译机制失调​​。综合这些观察结果的流行模型 是翻译降低了能量消耗，从而提高了缺氧生存率。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 优先在缺氧条件下翻译。因此，流行的“能量学”模型无疑是过度的。 过于简单化，也许完全不正确。我们的实验室对线虫秀丽隐杆线虫进行了基因筛选 控制缺氧生存。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/RNA 减少了总体蛋白质合成和耗氧量。 然而，转化率和耗氧量的降低程度与水平无关。 耐缺氧能力。此外，我们还发现，当 在从缺氧中恢复期间启动，此时能量保存不再重要。这些 观察结果表明，翻译抑制通过复杂的机制来防止缺氧，而不仅仅是简单地 降低能源消耗。我们建议使用线虫中强大的遗传工具来了解 翻译机制控制缺氧生存的复杂机制。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耐缺氧能力的生产途径并研究其机制 他们通过以下具体目标来确定缺氧生存。目标 1：定义路径 翻译机制借此调节缺氧损伤。我们将识别翻译中的突变 产生耐缺氧性的机械基因，还将识别阻止缺氧的基因突变 这些翻译突变体具有耐缺氧性。这些基因将被放置在途径中及其作用 将确定翻译突变。目标 2：确定代谢和生理 翻译机制调节与耐缺氧相关的后果。通过这些 目标是我们将对翻译机器如何控制缺氧有更全面的了解 生存以及该机制调节的后果。