Heat shock proteins in brain ischemia and stroke

描述(由申请人提供)： 中风在退伍军人中是一种常见的疾病，治疗方法很少。我们的实验室和我们的合作者的工作重点是热休克蛋白的保护潜力，即高度诱导的70kD热休克蛋白(HSP70)。由于其伴侣功能，HSP70似乎具有细胞保护特性，可能导致新生蛋白质折叠的增强和防止蛋白质聚集。然而，相关领域的研究表明，热休克蛋白似乎对缺血性细胞死亡的许多方面产生了积极影响。我们之前已经证明，HSP70的过度表达或其药物诱导通过抑制炎症和上调抗凋亡蛋白Bcl-2来保护细胞。其他研究表明，HSP70通过阻止细胞色素c从线粒体释放或抑制caspase激活来阻止细胞凋亡。通过与韩国延世大学的Jong Eun Lee博士的合作，我们发现Dynamin是一种基本上被HSP70过度表达抑制的蛋白质。Dynamin是一种GTP酶，通过将包被网状蛋白的小管从质膜上分离出来，参与受体介导的内吞作用。它在缺血性脑细胞死亡中的作用完全未知，但已被认为通过将死亡受体Fas转运到细胞表面来促进细胞凋亡。在这一应用中，我们建议进一步探讨HSP70通过干扰动力蛋白Fas的输出来保护大脑免受中风的这些观察结果，并解决动力蛋白作为治疗靶点的意义。具体目标1：确定动力蛋白抑制是否具有保护性，以及它的抑制是否与HSP70的保护有关。具体目标2：确定动力蛋白、Fas和热休克蛋白70抑制动力蛋白之间是否存在联系。具体目标3：确定HSP70如何调节动力蛋白的表达和/或功能。

DESCRIPTION (provided by applicant): Stroke is a common affliction among veterans, and treatments are few. Work by our labs and those of our collaborators' have focused on the protective potential of heat shock proteins, namely, the highly inducible 70 kD heat shock protein (HSP70). HSP70 appears to have cytoprotective properties by nature of its chaperone functions, presumably leading to enhancement of nascent protein folding and prevention of protein aggregation. However, work in related fields has shown that HSPs appear to positively influence many aspects of ischemic cell death. We previously showed that overexpression of HSP70 or its pharmacological induction protects by inhibiting inflammation and upregulating the anti-apoptotic protein, Bcl-2. Others have shown the HSP70 blocks apoptosis by preventing cytochrome c release from the mitochondria or inhibiting caspase activation. Through collaborative work with Dr. Jong Eun Lee (Yonsei University, S. Korea), we identified dynamin as one protein substantially suppressed by HSP70 overexpression. Dynamin is a GTPase involved in receptor- mediated endocytosis through detaching clathrin-coated vesciles from the plasma membrane. Its role in ischemic brain cell death is completely unknown, but has been implicated in facilitating apoptosis by trafficking the death receptor Fas to the cell surface. In this application, we propose to further explore these observations that HSP70 protects the brain against stroke by interfering with dynamin export of Fas, and to address the implications of dynamin as a therapeutic target. Specific aim 1: Determine whether dynamin inhibition is protective, and if its suppression is linked to protection by HSP70. Specific aim 2: Determine whether there is a link between dynamin, fas and dynamin inhibition by HSP70. Specific aim 3: Determine how HSP70 regulates dynamin expression and/or function.