Heat shock proteins in brain ischemia and stroke

描述（由申请人提供）： 中风是退伍军人中常见的疾病，治疗方法很少。我们实验室和我们合作者的工作集中在热休克蛋白的保护潜力上，即高度诱导的70 kD热休克蛋白（HSP 70）。HSP 70似乎具有细胞保护特性，其分子伴侣功能的性质，可能导致新生蛋白质折叠的增强和蛋白质聚集的预防。然而，相关领域的工作表明，热休克蛋白似乎积极影响缺血性细胞死亡的许多方面。我们以前的研究表明，过度表达HSP 70或其药理学诱导通过抑制炎症和上调抗凋亡蛋白Bcl-2来保护。其他人已经表明HSP 70通过阻止细胞色素c从线粒体释放或抑制半胱天冬酶激活来阻断细胞凋亡。通过与李钟恩博士（延世大学，S。Korea），我们鉴定了发动蛋白作为一种被HSP 70过表达实质上抑制的蛋白。发动蛋白是一种通过将网格蛋白包被的囊泡从质膜上分离而参与受体介导的内吞作用的GTP酶。其在缺血性脑细胞死亡中的作用是完全未知的，但已经涉及通过将死亡受体Fas运输到细胞表面来促进细胞凋亡。在本申请中，我们建议进一步探讨这些观察结果，即HSP 70通过干扰Fas的动力蛋白出口来保护大脑免受中风，并解决动力蛋白作为治疗靶点的影响。具体目标1：确定发动蛋白抑制是否具有保护作用，以及其抑制是否与HSP 70的保护作用有关。具体目标2：确定发动蛋白、Fas和HSP 70对发动蛋白的抑制之间是否存在联系。具体目标3：确定HSP 70如何调节发动蛋白的表达和/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.