Anesthetics and Stress Proteins in Brain Cell Injury

描述（由申请人提供）：中风是美国第三大死亡原因和最常见的神经功能障碍原因。虽然很多工作都集中在大脑神经元的损伤上，但基本上没有一种从这个角度开发的疗法在临床试验中被证明是有效的。最近的工作强调了神经胶质细胞在正常大脑和中风等损伤后发挥的重要和多方面的作用。长期目标是了解星形胶质细胞和小胶质细胞在中风中的有益和有害作用，以确定减少脑损伤的新靶点。70 kDa家族的热休克蛋白已被证明在中风动物模型中具有保护作用，但迄今为止，该家族中只有一个成员，即胞质Hsp72被广泛研究。中风后的脑损伤涉及氧化应激和钙超载，这两者都涉及线粒体和内质网的损伤。这两种细胞器在决定脑细胞是否能在缺血性损伤中存活中起着关键作用，因为它们密切参与处理钙超载和自由基，这是缺血性损伤的标志。本研究的第一个目的是研究两个Hsp70家族成员定位于这些细胞器，Hsp75定位于线粒体，Hsp78定位于内质网，在多大程度上保护大脑免受局灶性缺血和调节胶质细胞激活。这一目标包括通过改变线粒体代谢功能和氧化应激调节炎症的研究。第二个目标针对单个胶质细胞类型对中风的贡献。细胞质Hsp72在所有细胞类型中表达时都具有保护作用，将选择性地靶向星形胶质细胞或小胶质细胞，以确定仅限于这些细胞的过度表达是否足以保护大脑和保存神经元。小胶质细胞和星形胶质细胞的激活在中风的炎症反应中是重要的，Hsp72过表达已被证明可以调节这种反应并减少损伤。靶向表达对炎症的影响有待观察。由于细胞功能的许多方面在缺血期间同时发生改变，因此迄今为止很难确定决定结果的关键途径和机制。在第三个目标中，将开发炎症和凋亡细胞死亡信号通路的动态计算模型，包括Hsp70的调节。这将允许使用计算工具来确定中风触发的分子信号相互作用中使用的关键控制策略。该模型将通过生物学实验进行验证，然后用于识别炎症和缺血应激引起的调节策略。这种动态计算分析将确定干预最有可能对结果产生强烈影响的点。通过从几个互补的角度来解决这个问题，将确定新的脑保护候选物。中风是美国第三大死亡原因，也是导致神经系统残疾的最常见原因。这项研究的目的是找到减少中风引起的脑损伤的新方法，当这些方法转化为临床应用时，可以通过减少中风引起的损伤来改善中风患者的生活。

DESCRIPTION (provided by applicant): Stroke is the third leading cause of death and the most common cause of neurological disability in the US. Although much work has focused on damage to neurons in the brain, essentially none of the therapies developed from this perspective has proven efficacious in clinical trials. Recent work has highlighted the important and multifaceted roles that glial cells play both in normal brain and following insults like stroke. The long term goal is to understand both the beneficial and deleterious effects of astrocytes and microglia in stroke to identify new targets to reduce brain injury. Heat shock proteins of the 70 kDa family have been shown to be protective in animal models of stroke, but to date only a single member of this family, the cytosolic Hsp72, has been extensively studied. Brain injury following stroke is known to involve oxidative stress and calcium overload, both of which are implicated in damage to both mitochondria and the endoplasmic reticulum. Both of these organelles play key roles in determining whether brain cells can survive ischemic injury, because they are intimately involved in dealing with the calcium overload and the free radicals that are hallmarks of ischemic injury. The first aim of this proposal will study the extent to which two Hsp70 family members localized to these organelles, Hsp75 to mitochondria and Hsp78 to endoplasmic reticulum, protect the brain from focal ischemia and modulate glial activation. This aim includes studies of modulation of inflammation by alteration of mitochondrial metabolic function and oxidative stress. The second aim targets the contribution of individual glial cell types to stroke. The cytosolic Hsp72, which is protective when expressed in all cell types, will be targeted selectively to either astrocytes or microglia to determine if overexpression restricted to these cells is sufficient to protect the brain and preserve neurons. Activation of microglia and astrocytes is important in the inflammatory response to stroke, and Hsp72 overexpression has been shown to modulate this response and reduce injury. The effect on inflammation of targeted expression will be determined. Because many aspects of cell function are altered simultaneously during ischemia, it has been difficult, to date, to identify the key pathways and mechanisms that determine outcome. In the third aim a dynamical computational model of inflammatory and apoptotic cell death signaling pathways, including modulation by Hsp70, will be developed. This will allow the use of computational tools to identify critical control strategies used in the molecular signaling interactions triggered by stroke. The model will be validated by biological experiments, and then used to identify the regulatory strategies evoked in response to inflammatory and ischemic stress. This dynamical computational analysis will identify the points at which intervention is most likely to strongly influence outcome. By approaching the problem from several complementary angles, new candidates for brain protection will be identified. PUBLIC HEALTH RELEVANCE Stroke is the third leading cause of death and the most common cause of neurological disability in the US. The goal of this research is to identify new ways to reduce the brain injury caused by stroke which when translated to clinical use could improve the lives of stroke victims by reducing the damage caused by stroke.