HuR Regulation of HSP 70 in Brain Reperfusion

描述（申请人提供）：DeGracia实验室的长期目标是研究脑缺血/再灌注（l/R）损伤的基本细胞病理学，为开发有效的临床治疗提供基础。l/R损伤是与中风和心脏骤停及复苏相关的发病率和死亡率的基础。目前还没有有效的治疗方法来阻止脑l/R后的神经元死亡。在这里，我们提出了一种新的调控70 kDa诱导热休克蛋白HSP70的机制。l/ r抵抗神经元（如海马CA3）在再灌注早期合成HSP70蛋白。l/ r易感神经元（海马CAI）可以转录大量hsp70 mRNA，但不能合成hsp70蛋白。我们的初步数据显示mrna稳定蛋白HuR的核输出与HSP70翻译相关。HuR结合含有ARE的mRNA，而hsp70 mRNA含有ARE序列。为了评估HuR在调节HSP70合成中的作用，我们提出以下目标：目的：确定HuR和hsp70 mRNA在再灌注海马中的亚细胞定位。目的是确定hsp70 mRNA的亚细胞位置是否与HuR的位置相关，以及hsp70 mRNA的位置在缺血抵抗CA1和缺血易损CAS神经元之间是否存在差异。2. 确定HuR核出口是否与HSP70翻译有因果关系。5'腺苷单磷酸活化蛋白激酶（AMPK）的激活导致HuR的核保留，并恶化脑卒中的预后。在AMPK的药理激活或抑制下，HuR亚细胞定位、HSP70翻译和细胞存活将在缺血和再灌注后被确定。

DESCRIPTION (provided by applicant): The long-term goal of the DeGracia laboratory is to investigate the basic cellular pathology of ischemia/reperfusion (l/R) brain injury to provide a foundation to develop effective clinical therapies. l/R injury underlies the morbidity and mortality associated with stroke and cardiac arrest and resuscitation. There are currently no effective therapies to halt neuronal death following brain l/R. Here, we propose a novel mechanism of regulation of the 70 kDa inducible heat shock protein HSP70. l/R-resistant neurons (e.g. hippocampal CA3), synthesize HSP70 protein early in reperfusion. l/R-vulnerable neurons (hippocampal CAI), transcribe ample hsp70 mRNA, but fail to synthesize the HSP70 protein. Our preliminary data shows nuclear export of the mRNA-stabilizing protein HuR correlates with HSP70 translation. HuR binds ARE-containing mRNAs, and hsp70 mRNA contains an ARE sequence. To assess the role of HuR in regulating HSP70 synthesis, we propose the following aims: 1. To determine the subcellular localization of HuR and hsp70 mRNA in the reperfused hippocampus. This aim will determine whether the subcellular location of hsp70 mRNA correlates with the location of HuR and whether the location of hsp70 mRNA differs between ischemia-resistant CA1 and ischemia-vulnerable CAS neurons. 2. To determine if HuR nuclear export is causally linked to HSP70 translation. 5' adenosine monophosphate- activated protein kinase (AMPK) activation causes nuclear retention of HuR and worsens stroke outcome. HuR subcellular localization, HSP70 translation, and cell survival will be determined following ischemia and reperfusion in the presence of pharmacologic activation or inhibition of AMPK. Public Heath Relevance: Thousands die from ischemic brain injury annually. These studies will increase our understanding of why the brain is damaged following stroke or cardiac arrest and potentially contribute to development of treatments.