Mechanisms and Treatment of CNS Edema

中枢神经系统水肿的机制和治疗

• 批准号: 8862551
• 负责人: CAROL M TROY
• 金额: $ 35万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8862551
• 关键词: Affinity; BIRC4 gene; Blocking Antibodies; Blood Vessels; Blood flow; Brain; Brain Edema; Caspase; Cause of Death; Cells; Cerebral Edema; Cerebral Ischemia; Cerebrum; Cessation of life; Cleaved cell; Data; Development; Edema; Endothelial Cells; Engineering; Extravasation; Family; Gelatinase B; Health; Impairment; Injury; Ischemia; Ischemic Stroke; Knock-out; Knockout Mice; Knowledge; Lead; Ligands; Liquid substance; Matrilysin; Measures; Mediating; Medical; Mus; NGFR Protein; Natural History; Nerve Degeneration; Neuronal Dysfunction; Neurons; Operative Surgical Procedures; Pathogenesis; Pathway interactions; Peptide Hydrolases; Pericytes; Procedures; Process; Proteins; Regulation; Resistance; Risk; Signal Pathway; Signal Transduction; Stroke; Stroke prevention; Testing; Therapeutic; Therapeutic Intervention; Tight Junctions; Time; Tissue Inhibitor of Metalloproteinase-1; Tissues; caspase-3; caspase-9; disability; effective therapy; in vitro Model; in vivo; inhibitor/antagonist; mutant; neuroprotection

DESCRIPTION (provided by applicant): Stroke is the 3rd largest cause of death and the largest cause of disability in the U.S., yet there are no effective therapies for the vast majorityof cases. Present therapeutic options merely aim to restore blood flow in the hopes of salvaging at risk tissue, but offer no targeted neuroprotection. Development of neuroprotective therapies has been hindered by lack of knowledge of the signaling pathways critical in secondary injury following ischemic stroke. For more than a decade, the caspase family of death proteases has been implicated in cerebral ischemia and neurodegeneration. Recent evidence shows that distinct caspase pathways are activated during ischemia. We have identified the caspase-9/-6 pathway as responsible for neuronal dysfunction and death after ischemia. Our data show that targeting caspase-9 activity provides substantial neuroprotection following an ischemic insult. Moreover, we find that caspase-9 activity is required for two aspects of ischemic pathogenesis: 1) neuronal degeneration and 2) the development of cerebral edema. Edema is caused by a loss of vascular integrity, rather than death of endothelial cells and pericytes in the blood vessels (BV). The elimination of tight junctions between these cells allows extravasation of fluid from small intracranial BVs. Edema formation is a major contributor to death and disability in severe stroke. Medical therapies and surgical decompressive procedures have only minimally altered the natural history of this pathogenic process. In our studies, a cell permeant caspase-9 inhibitor, Pen1-XBIR3, reduces caspase-9 activity and concomitantly abolishes edema. This finding opens the question of whether caspase-9 activity is a direct cause of edema through the impairment of vascular integrity of small cerebral BVs. Our preliminary data suggest that active caspase-9 regulates edema by decreasing the expression of matrix metalloproteinase 9 (MMP-9). Our data also show that expression of the precursor of mature NGF, proNGF, increases during stroke. ProNGF is a high affinity ligand for p75NTR, and we have shown that signaling through p75NTR activates caspase-9. p75NTR is found in small BVs in the brain, and expression of p75NTR increases during stroke. Our preliminary data also show that activated caspase-9 is present in BVs, and that caspase-9 inhibition prevents the stroke-induced expression of MMP-9. We now propose the hypothesis that the development of edema in stroke is mediated by proneurotrophin (proNT) signaling through p75NTR, which activates caspase-9 in small BVs to cleave substrates vital to the integrity of the vessels. We will utilize in vivo an in vitro models to examine this hypothesis with the following Specific Aims: Aim 1: To determine if induction of proNTs triggers caspase-9 activation in small BVs. Aim 2: To determine if signaling via p75NTR activates caspase-9 and leads to edema. Aim 3: To determine how caspase-9 cleavage of substrates leads to loss of vascular integrity.

描述（由申请人提供）：中风是美国第三大死亡原因和第一大残疾原因，然而对于绝大多数病例还没有有效的治疗方法。目前的治疗选择仅仅旨在恢复血流，希望挽救处于危险中的组织，但没有提供有针对性的神经保护。由于缺乏对缺血性卒中后继发性损伤的关键信号通路的了解，神经保护治疗的发展受到阻碍。十多年来，死亡蛋白酶的半胱天冬酶家族与脑缺血和神经变性有关。最近的证据表明，不同的半胱天冬酶途径在缺血期间被激活。我们已经确定caspase-9/-6通路是缺血后神经元功能障碍和死亡的原因。我们的数据显示，靶向caspase-9活性在缺血性损伤后提供了实质性的神经保护。此外，我们发现半胱天冬酶-9活性是缺血性发病机制的两个方面所必需的：1）神经元变性和2）脑水肿的发展。水肿是由血管完整性的丧失引起的，而不是血管（BV）中内皮细胞和周细胞的死亡。这些细胞之间紧密连接的消除允许液体从颅内小BV外渗。水肿形成是导致严重卒中死亡和残疾的主要因素。药物治疗和外科减压手术只能最小限度地改变这种致病过程的自然史。在我们的研究中，一种细胞渗透性半胱天冬酶-9抑制剂Pen 1-XBIR 3降低了半胱天冬酶-9的活性，同时消除了水肿。这一发现提出了一个问题，即caspase-9活性是否是通过损害小脑BV的血管完整性而导致水肿的直接原因。我们的初步数据表明，活性半胱天冬酶-9调节水肿通过减少基质金属蛋白酶9（MMP-9）的表达。我们的数据还表明，表达的前体成熟的神经生长因子，proNGF，增加中风期间。ProNGF是p75 NTR的高亲和力配体，我们已经证明通过p75 NTR的信号传导会激活半胱天冬酶-9。p75 NTR存在于脑内的小BV中，并且p75 NTR的表达在中风期间增加。我们的初步数据还表明，激活的caspase-9存在于BV中，并且caspase-9抑制可防止卒中诱导的MMP-9表达。我们现在提出这样的假设，即脑卒中水肿的发生是由前神经营养因子（proNT）通过p75 NTR信号传导介导的，p75 NTR激活小BV中的半胱天冬酶-9以切割对血管完整性至关重要的底物。我们将利用体内和体外模型来检验这一假设，具体目的如下：目的1：确定proNT的诱导是否触发小BV中的半胱天冬酶-9活化。目的2：确定通过p75 NTR的信号转导是否激活caspase-9并导致水肿。目的3：确定半胱天冬酶-9切割底物如何导致血管完整性丧失。