Stress Granules Cause Translation Arrest In Ischemic Vulunerable Neurons

心脏骤停和卒中复苏后发生脑缺血再灌注(I/R)损伤，发病率和死亡率较高。目前还没有临床上有效的治疗方法。 由于对细胞损伤的不完全理解，导致细胞死亡。我的实验室的长期目标是研究脑I/R引起神经元死亡的机制 允许开发有效的治疗方法。 在短暂性全脑I/R后，蛋白质合成抑制与海马CA1区锥体神经元的选择性死亡密切相关。这种不可逆的翻译抑制及其与细胞死亡的关系尚不清楚。应激颗粒是 在细胞应激期间隔离不活跃的翻译机械的细胞质颗粒。我们提出了令人信服的证据，即应激颗粒改变是持续翻译停滞的核心。 缺血易损的海马CA1区神经元。我们的具体目标是： 1.探讨不可逆性翻译停滞的机制。我们将利用互补的显微镜和生化方法来分析应激颗粒的功能组成。我们将比较缺血抵抗CA3和缺血易损CA1中的应激颗粒 早期再灌流到易损神经元细胞死亡的程度。 2.探讨缺血预适应(IPC)对再灌流神经元应激颗粒组成和行为的影响。IPC可防止脆弱的CA1神经元中的细胞死亡和持续翻译停滞。我们将评估IPC对应激颗粒行为和 CA1神经元的组成、蛋白质合成速率和细胞死亡。 3.为了证明持续性翻译停滞与脑I/R后神经元死亡的因果关系，将使用抗生素蛋白合成抑制剂来预测性地改变再灌流中的应激颗粒。 我们将检测其对海马神经元蛋白质合成率、应激颗粒组成和行为以及细胞死亡的影响。通过对持续翻译停顿和翻译停顿之间的关系进行综合检查 对于I/R诱导的细胞死亡，我们的具体目标是解决阻碍该领域进展的一个问题：再灌流神经元中蛋白质合成的不可逆转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.