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

描述（由申请人提供）：小泛素样修饰物（SUMO）偶联调节所有主要的细胞通路，包括与基因表达和基因组稳定性、蛋白质质量控制、蛋白质蛋白酶体降解和DNA损伤修复相关的通路。短暂性脑缺血大量激活SUMO偶联，导致SUMO2/3偶联蛋白水平急剧上升。细胞培养研究表明，缺血后激活SUMO2/3偶联是一种保护性应激反应。然而，SUMO偶联在完整脑缺血后神经元命运中的作用，以及SUMO偶联与短暂缺血受损功能恢复之间的机制和途径尚不清楚。如果没有这方面的知识，SUMO偶联通路就不太可能被用于治疗目的。我们的长期目标是了解如何操纵SUMO偶联途径用于预防和治疗目的。这一特殊应用的目的是阐明单个SUMO同源物在缺血性应激神经元恢复中的作用，并确定所涉及的机制和途径。核心假设是SUMO共轭在调节通路中起关键作用，这些通路对缺血后神经元的死亡/生存决策至关重要。这个假设是根据我们实验室的数据提出的。提出这项研究的基本原理是，在我们验证了SUMO偶联在体内缺血后神经元中的保护作用并确定了潜在的机制和途径后，我们将为设计临床相关病理状态相关的预防和治疗干预新策略建立一个重要的平台

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.