ROLE OF HSP 25 IN THE ASTROCYTE RESPONSE AND RECOVERY FROM SPINAL CORD INJURY

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 脊髓损伤(SCI)和继发性细胞死亡部分与缺血有关。少突胶质细胞和星形胶质细胞的存活对于维持白质中的细胞相互作用和限制继发性损伤至关重要。本研究的目的是研究热休克蛋白(HSPs)在缺氧/缺血暴露的少突胶质细胞和星形胶质细胞中的诱导和相互作用，并确定与更高的缺血耐受性相关的分子和信号通路。各种应激诱导的热休克蛋白参与蛋白质的折叠和修复，并与脑和脊髓的细胞缺血耐受有关。我们将验证这一假设，即在脊髓损伤后，HSP表达的诱导调节神经胶质细胞存活的信号通路，以维持少突胶质细胞/星形胶质细胞的完整性以及与神经元的相互作用。本研究的具体目的是：1.检测缺氧/缺血的少突胶质细胞、星形胶质细胞和脊髓挫伤后热休克蛋白的表达情况。2.探讨热休克蛋白对少突胶质细胞和星形胶质细胞在缺氧/缺血损伤和脊髓损伤后存活的影响。3.探讨热休克蛋白相关细胞保护机制(S)及热休克蛋白结合蛋白在脊髓损伤后缺氧/缺血存活途径和细胞死亡中的作用。利用胚胎少突胶质细胞前体(OPC)分化为少突胶质细胞或星形胶质细胞，并暴露在缺氧/缺血环境中，我们将评估热休克蛋白在细胞模型中的表达，并将HSP表达水平与细胞存活相关联。此外，我们还将研究脊髓损伤后脊髓组织中热休克蛋白的表达情况。HSP基因的过表达或沉默对少突胶质细胞/星形胶质细胞存活、细胞缺氧/缺血和脊髓损伤延迟损伤的影响，以及实验性HSP诱导的全动物对脊髓损伤后继发性损伤的影响将被确定。最后，我们将使用蛋白质组学方法来鉴定在少突胶质细胞和星形胶质细胞中，以及在脊髓损伤后不同受损区域中，热休克蛋白与低氧/缺血诱导的蛋白质之间的相互作用。因此，我们将表征细胞对缺氧/缺血的差异敏感性的信号通路，并确定潜在的脊髓损伤干预靶点。这些研究将确定新的治疗方法，以保护受损脊髓中的少突胶质细胞支持，抑制细胞凋亡，减少迟发性白质损伤。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Spinal cord injury (SCI) and subsequent secondary cell death partially involves an ischemic component. Oligodendrocytes and astrocytes survival is critical to maintain cellular interactions in the white matter and limit secondary injury damage. The purpose of this proposal is to study heat shock proteins (hsps) induction and interactions in hypoxia/ischemia-exposed oligodendrocytes and astrocytes and identify molecules and signaling pathways associated with higher tolerance to ischemia. Hsps induced by various stresses are involved in protein refolding and repair, and have been implicated in cellular ischemic tolerance in brain and in spinal cord. We will test the hypothesis that after SCI, induction of hsp expression modulates glial cell survival signaling pathways to preserve oligodendrocyte / astrocyte integrity and interactions with neurons. The specific aims of this proposal are: 1. To examine the expression profile of heat shock proteins induced in hypoxic/ischemic oligodendrocytes and astrocytes in culture, and in contused spinal cord. 2. To determine the effect of hsp on oligodendrocytes and astrocytes survival to hypoxia/ ischemic injury and after SCI. 3. To determine the mechanism(s) of hsp-related cell protection and the role of hsp binding proteins in hypoxia/ ischemia survival pathways and in cell death after SCI. Using embryonic oligodendrocyte precursors (OPCs) differentiated to either oligodendrocytes or astrocytes and exposed to hypoxia/ischemia, we will assess heat shock proteins expression in a cellular model and correlate the levels of hsp expression with cell survival. In addition, we will characterize the profile of hsps induced by SCI in rodent spinal cord. The effect of hsp gene overexpression or silencing on oligodendrocytes/astrocytes survival to cellular hypoxia/ ischemia and on SCI-induced delayed injury will be determined, as well as the effect of experimental hsp induction in the whole animal on secondary injury-induced damage after SCI. Finally, we will use proteomic approaches to identify protein-protein interactions with hsps induced by hypoxia/ischemia in oligodendro- cytes and in astrocytes, and in differentially damaged areas of the spinal cord after SCI. Thus, we will characterize signaling pathways underlying cellular differential sensitivity to hypoxia/ischemia and identify potential intervention targets in SCI. These studies will identify novel therapeutic approaches to preserve oligodendroglial support in injured spinal cord, inhibit apoptosis, and reduce delayed white matter injury.