Bc1-2 Family Proteins in the Ischemic Neuronal Injury

缺血性神经元损伤中的 Bc1-2 家族蛋白

• 批准号: 6569380
• 负责人: XIAO-MING YIN
• 金额: $ 24.46万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-15 至 2006-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6569380
• 关键词: Bax gene /protein; SDS polyacrylamide gel electrophoresis; apoptosis; brain; cerebral ischemia /hypoxia; cerebrovascular occlusions; cysteine endopeptidases; cytochrome c; flow cytometry; gene targeting; genetically modified animals; immunofluorescence technique; laboratory mouse; mitochondria; necrosis; neurons; protein protein interaction; protein structure function; terminal nick end labeling; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): Vascular occlusion or disruption resulted from stroke, or brain attack, can lead to brain ischemia and hypoxia that can result in serious neuronal injury. While damaged neurons often die from necrosis, significant amount of neurons die from apoptosis, or programmed cell death. Studies on the basic mechanisms of apoptosis have established that a group of cysteine proteases, i.e., caspases, are responsible for the execution of the death program. Caspases actively participate in the pathogenesis of ischemia/hypoxia-induced neuronal cell death, although how they are activated in this process is largely elusive. Bcl-2 family proteins are important apoptosis regulators and have been implicated in ischemic neuronal death. Two pro-apoptosis Bcl-2 family members, Bid and Bax, can activate caspases by triggering mitochondrial dysfunction including cytochrome c release. In our preliminary studies, we found that bid-deficient mice were significantly resistant to ischemic neuronal death in a focal ischemia model. In addition, mice deficient in both Bid and Bax demonstrated an even bigger resistance to the ischemic injury. Finally, at the molecular level, Bid and Bax can interact with each other and synergistically enhance each other's activity. We have thus formulated our hypothesis that both Bid and Bax are critical to the development of ischemia-induced neuronal apoptotic death by inducing mitochondrial dysfunction and activating the caspase cascade. Furthermore, while the two proteins may be activated by different mechanisms, they nevertheless accomplish the same goal of transmitting extracellular death stimuli to mitochondria and then initiate the execution in a collaborative fashion. We will test this hypothesis specifically from the following aspects: 1). To investigate the contribution of Bid and Bax to neuronal death in a murine focal ischemia model, 2). To define the role of Bid and Baxc in mitochondrial damage in neuronal cells with an in vitro neuronal injury model, and 3). To characterize the molecular interactions of Bid and Bax in inducing dysfunction of mitochondria isolated from the brain.

描述(申请人提供)：中风或脑发作引起的血管闭塞或中断，可导致脑缺血和缺氧，从而导致严重的神经元损伤。虽然受损的神经元经常死于坏死，但相当数量的神经元死于凋亡，或程序性细胞死亡。对细胞凋亡基本机制的研究已经证实，一组半胱氨酸蛋白酶，即caspase，负责死亡程序的执行。Caspase积极参与缺血/缺氧诱导的神经细胞死亡的发病机制，尽管在这一过程中它们是如何被激活的在很大程度上是未知的。BCL-2家族蛋白是重要的细胞凋亡调节因子，与缺血性神经元死亡密切相关。Bid和Bax这两个促凋亡的Bcl2家族成员可以通过触发线粒体功能障碍来激活caspase，包括细胞色素c的释放。在我们的初步研究中，我们发现BID缺陷小鼠在局灶性脑缺血模型中对缺血性神经元死亡具有显著的抵抗力。此外，缺乏Bid和Bax的小鼠对缺血损伤表现出更大的抵抗力。最后，在分子水平上，Bid和Bax可以相互作用，协同增强彼此的活性。因此，我们提出了我们的假设，即Bid和Bax都是通过诱导线粒体功能障碍和激活caspase级联而在缺血诱导的神经元凋亡死亡的发展中起关键作用的。此外，虽然这两种蛋白可能被不同的机制激活，但它们完成了将细胞外死亡刺激传递到线粒体并以协作方式启动执行的相同目标。我们将从以下几个方面具体检验这一假说：1)。探讨Bid和Bax在小鼠局灶性脑缺血模型神经元死亡中的作用。用体外神经元损伤模型确定Bid和Baxc在神经细胞线粒体损伤中的作用；探讨Bid和Bax在诱导脑线粒体功能障碍中的分子相互作用。