Anesthetics and Stress Proteins in Brain Cell Injury

描述(申请人提供)：中风是美国第三大致死原因，也是导致神经性残疾的最常见原因。尽管许多工作都集中在对脑神经元的损伤上，但从这个角度开发的疗法基本上没有一种在临床试验中被证明是有效的。最近的研究强调了神经胶质细胞在正常大脑和中风等侮辱后扮演的重要和多方面的角色。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影响，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，但到目前为止，该家族中只有一个成员-胞质HSP72-得到了广泛的研究。众所周知，中风后的脑损伤涉及氧化应激和钙超载，这两者都与线粒体和内质网的损伤有关。这两个细胞器都在决定脑细胞是否能存活下来方面发挥着关键作用，因为它们与处理钙超载和自由基密切相关，而钙超载和自由基是缺血性损伤的标志。这项提议的第一个目的是研究Hsp70家族的两个成员在多大程度上定位于这些细胞器，Hsp75定位于线粒体，Hsp78定位于内质网，从而保护大脑免受局灶性脑缺血的影响，并调节胶质细胞的激活。这一目标包括通过改变线粒体代谢功能和氧化应激来调节炎症的研究。第二个目标是研究不同类型的胶质细胞对中风的影响。胞浆HSP72在所有类型的细胞中都具有保护性，它将选择性地针对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卒中的炎症反应中很重要，HSP72的过度表达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将被确定。由于细胞功能的许多方面在缺血期间同时改变，到目前为止，确定决定结果的关键途径和机制一直是困难的。在第三个目标中，将建立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识别中风引发的分子信号相互作用中使用的关键控制策略。该模型将通过生物实验进行验证，然后用于识别在应对炎症和缺血应激时诱发的调控策略。这一动态计算分析将确定干预最有可能强烈影响结果的点。通过从几个互补的角度来处理这个问题，将确定脑保护的新候选者。中风是美国第三大致死原因，也是导致神经性残疾的最常见原因。这项研究的目的是寻找新的方法来减少中风造成的脑损伤，当转化为临床使用时，可以通过减少中风造成的损害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.