Stress Granules Cause Translation Arrest In Ischemic Vulunerable Neurons

脑缺血再灌注（I/R）损伤发生在心脏骤停和中风复苏后，并导致高发病率和死亡率。没有临床有效的治疗方法 因为对导致细胞死亡的细胞损伤级联的不完全理解。本实验室的长期目标是研究脑I/R引起神经元死亡的机制， 从而开发出有效的治疗方法。 短暂性全脑缺血再灌注后海马CA 1区锥体神经元的选择性死亡与蛋白质合成抑制有显著相关性。这种不可逆的翻译停滞的机制及其与细胞死亡的关系尚不清楚。应力颗粒是 在细胞应激期间隔离非活性翻译机器的细胞质颗粒。我们提出了令人信服的证据表明，应激颗粒的改变是核心的持续翻译逮捕， 缺血性海马CA 1神经元。我们的具体目标是： 1.探讨不可逆翻译停滞的机制。我们将利用互补的显微镜和生物化学方法分析应激颗粒的功能组成。 我们将比较缺血抵抗性CA 3和缺血易损性CA 1中的应激颗粒， 早期再灌注到脆弱神经元的细胞死亡点。 2.探讨缺血预处理（IPC）对再灌注神经元应激颗粒组成和行为的影响。IPC防止脆弱的CA 1神经元中的细胞死亡和持续的翻译停滞。我们将评估IPC对应激颗粒行为的影响， 组成，蛋白质合成率和细胞死亡的CA 1神经元。 3.表明持续性翻译停滞与脑I/R后神经元死亡存在因果关系。 抗生素蛋白合成抑制剂将用于可预测地改变再灌注中的应激颗粒。 海马神经元，我们将研究对蛋白质合成速率，应激颗粒组成和行为以及再灌注海马神经元细胞死亡的影响。 通过对持续翻译停滞与翻译障碍之间关系的综合研究， I/R诱导的细胞死亡，我们的特定目标解决了一个一直阻碍该领域进展的问题：再灌注神经元中蛋白质合成的不可逆抑制如何导致细胞死亡。

Ischemia and reperfusion (I/R) injury of the brain occurs following resuscitation from cardiac arrest and stroke, and results in high morbidity and mortality. There is no clinically effective treatment because of an incomplete understanding of the cellular injury cascades leading to cell death. The long- term goal of my laboratory is to investigate the mechanisms of neuronal death caused by brain I/R to allow for the development of effective treatments. There is a striking correlation between protein synthesis inhibition and the selective death of hippocampal CA1 pyramidal neurons following transient global brain I/R. The mechanism of this irreversible translation arrest and its relationship to cell death is unknown. Stress granules are cytoplasmic particles that sequester inactive translational machinery during cellular stress. We present compelling evidence that stress granule alterations are central to persistent translation arrest in ischemic-vulnerable hippocampal CA1 neurons. Our Specific Aims are: 1. To investigate the mechanism of irreversible translation arrest. We will analyze the functional composition of stress granules utilizing complementary microscopic and biochemical approaches. We will compare stress granules in ischemic resistant CA3 and ischemic vulnerable CA1 from early reperfusion to the point of cell death of vulnerable neurons. 2. To identify the effect of ischemic preconditioning (IPC) on stress granule composition and behavior in reperfused neurons. IPC prevents both cell death and persistent translation arrest in vulnerable CA1 neurons. We will assess the effect of IPC on stress granule behavior and composition, protein synthesis rates, and cell death in CA1 neurons. 3. To show that persistent translation arrest is causally related to neuronal death following brain I/R. Antibiotic protein synthesis inhibitors will be used to predictably alter stress granules in reperfused hippocampal neurons, and we will examine the effect on protein synthesis rates, stress granule composition and behavior and cell death in reperfused hippocampal neurons. By providing an integrated examination of the relationship between persistent translation arrest and I/R-induced cell death, our Specific Aims address a problem that has been a barrier to progress in the field: how irreversible inhibition of protein synthesis in reperfused neurons causes cell death.