Role of SUMO Conjugation in Ischemia: Significance, Mechanisms and Pathways

描述(申请人提供)：小泛素样修饰物(SUMO)结合调节所有主要的细胞途径，包括与基因表达和基因组稳定性、蛋白质质量控制、蛋白质的蛋白酶体降解和DNA损伤修复相关的途径。短暂性脑缺血大量激活相扑结合，导致SUMO2/3结合蛋白水平显著升高。细胞培养研究表明，缺血后SUMO2/3结合的激活是一种保护性应激反应。然而，相扑结合在完整脑缺血后神经元命运中的作用，以及将相扑结合与短暂性脑缺血损伤的功能恢复联系起来的机制和途径尚不清楚。如果没有这方面的知识，相扑结合途径不太可能被操纵用于治疗目的。我们的长期目标是了解如何操纵相扑结合途径以达到预防和治疗的目的。这一特殊应用的目的是阐明单个相扑类似物在神经元从缺血应激中恢复的作用，并确定涉及的机制和途径。中心假说是，相扑共轭在调节对缺血后神经元的死亡/生存决定至关重要的通路中起着关键作用。这一假设是根据我们实验室提供的数据提出的。提出这项研究的基本原理是，在我们验证了相扑结合在活体缺血后神经元中的保护作用并确定了潜在的机制和途径之后，我们将建立一个重要的平台，为设计与临床相关的病理状态的预防和治疗干预的新策略奠定基础。 血液供应不足的短暂发作。基于强有力的初步数据以及本实验室开发的新型相扑转基因和基因敲除动物模型，我们将通过下列特定目标验证这一假设：1)鉴定新型相扑转基因和基因剔除小鼠模型的特征；2)确定单个相扑类似物对缺血后神经细胞损伤和功能恢复的影响；3)确定相扑结合与缺血后神经细胞命运的关联；4)确定短暂性脑缺血如何影响泛素与相扑结合之间的串扰。这种方法是创新的，因为这是第一次使用相扑转基因和基因敲除动物并进行蛋白质组学分析来确定相扑结合在脑缺血中的作用。这项拟议的研究意义重大，因为我们希望揭示相扑共轭与缺血后神经元的活性和功能之间的联系。最终，这些知识有望转化为新的治疗策略，用于治疗与血液供应不足相关的病理状态，以及与相扑结合途径相关的其他疾病，包括糖尿病、心力衰竭和退行性疾病。

DESCRIPTION (provided by applicant): Small ubiquitin-like modifier (SUMO) conjugation modulates all major cellular pathways, including those associated with gene expression and genome stability, protein quality control, proteasomal degradation of proteins and DNA damage repair. Transient cerebral ischemia massively activates SUMO conjugation, resulting in a dramatic rise in levels of SUMO2/3-conjugated proteins. Cell culture studies suggest that the post- ischemic activation of SUMO2/3 conjugation is a protective stress response. However, the role of SUMO conjugation in the fate of post-ischemic neurons in the intact brain and the mechanisms and pathways that link SUMO conjugation to restoration of function impaired by transient ischemia are not known. Without this knowledge it is highly unlikely that the SUMO conjugation pathway can be manipulated for therapeutic purposes. Our long-term goal is to understand how to manipulate the SUMO conjugation pathway for preventive and therapeutic purposes. The objective of this particular application is to elucidate the role of individual SUMO paralogues in the recovery of neurons from ischemic stress and to identify the mechanisms and pathways involved. The central hypothesis is that SUMO conjugation plays a key role in modulating path- ways that are critical for death/survival decisions in post-ischemic neurons. This hypothesis has been formulated on the basis of data produced in our laboratory. The rationale for the proposed studies is that after we have verified the protective role of SUMO conjugation in post-ischemic neurons in vivo and have identified the underlying mechanisms and pathways, we will have established an important platform for designing new strategies for preventive and therapeutic interventions in clinically relevant pathological states associated with a transient episode of insufficient blood supply. Based on strong preliminary data and the development of novel SUMO transgenic and knockout animals in our laboratory, the hypothesis will be tested by pursuing the following specific aims: 1) Characterize new SUMO transgenic and knockout mouse models; 2) Determine the effects of individual SUMO paralogues on post-ischemic neuronal cell damage and functional recovery; 3) Determine how SUMO conjugation is linked to the fate of post-ischemic neurons; 4) Determine how transient ischemia affects the crosstalk between ubiquitin and SUMO conjugation. The approach is innovative because it is the first study to use SUMO transgenic and knockout animals and to per- form proteomic analyses to determine the role of SUMO conjugation in cerebral ischemia. The proposed research is significant, because we expect to uncover the mechanisms that link SUMO conjugation to the viability and function of post-ischemic neurons. Ultimately, such knowledge is expected to translate into new strategies for therapeutic intervention in pathological states associated with an episode of insufficient blood supply and in other disorders associated with the SUMO conjugation pathway, including diabetes, heart failure, and degenerative diseases.