HuR Regulation of HSP 70 in Brain Reperfusion

描述（由申请人提供）：DeGracia实验室的长期目标是研究缺血/再灌注（I/R）脑损伤的基本细胞病理学，为开发有效的临床治疗提供基础。I/R损伤是与中风、心脏骤停和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I/R后的神经元死亡。在这里，我们提出了一种新的机制，70 kDa的诱导热休克蛋白HSP 70的调节。l/R抗性神经元（例如海马CA 3）在再灌注早期合成HSP 70蛋白。I/R易损神经元（海马CAI）转录大量的HSP 70 mRNA，但不能合成HSP 70蛋白。我们的初步数据表明，核输出的mRNA稳定蛋白HuR与HSP 70的翻译。HuR结合含有ARE的mRNA，hsp 70 mRNA含有ARE序列。为了评估HuR在调节HSP 70合成中的作用，我们提出以下目的：1.目的：观察再灌注后海马HuR和hsp 70 mRNA的亚细胞定位。这一目的将确定hsp 70 mRNA的亚细胞位置是否与HuR的位置相关，以及hsp 70 mRNA的位置是否在缺血抵抗的CA 1和缺血脆弱的CAS神经元之间存在差异。2.确定HuR核输出是否与HSP 70翻译存在因果关系。5'腺苷一磷酸活化蛋白激酶（AMPK）激活导致HuR的核滞留和脑卒中结局. HuR亚细胞定位、HSP 70翻译和细胞存活将在存在AMPK的药理学活化或抑制的情况下在缺血和再灌注后测定。 公共卫生相关性：每年有数千人死于缺血性脑损伤。这些研究将增加我们对中风或心脏骤停后大脑受损原因的理解，并可能有助于治疗方法的发展。

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.