Astrocytes and ischemic brain injury

星形胶质细胞和缺血性脑损伤

基本信息

批准号：
8333004
负责人：
Rona G Giffard
金额：
$ 39.75万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-03-15 至 2017-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8333004
关键词：
Address Affect Aftercare Algorithms Apoptosis Apoptotic Astrocytes BCL2 gene Behavioral Biological Assay Brain Brain Ischemia Cell Death Cells Cerebral Ischemia Cessation of life Coculture Techniques Failure Family Family member Fright Functional disorder Funding Gene Expression Gene Family Gene Targeting Glial Fibrillary Acidic Protein Heart Arrest Hippocampus (Brain)Impairment In Vitro Individual Injury Ischemia Ischemic Brain Injury Label Life Luciferases Matrix Metalloproteinases Messenger RNA MicroRNAs Mitochondria Modeling Mutate Neurologic Neurological outcome Neurons Nucleotides Outcome Oxidative Stress Patients Prosencephalon Protein Family Proteins Publishing Reactive Oxygen Species Regulation Reperfusion Therapy Reporter Research Resuscitation Role Seeds Signal Transduction Small Interfering RNA Stress Survivors Testing Time Translating Untranslated Regions Up-Regulation Work cell type clinical application cytochrome c dentate gyrus disability genetic regulatory protein improved in vivo member mitochondrial membrane neuronal survival neuroprotection novel prevent response small hairpin RNA stroke therapy

项目摘要

DESCRIPTION (provided by applicant): One of the most feared disabilities in survivors of cardiac arrest is neurological impairment. Even brief global cerebral ischemia causes delayed loss of CA1 hippocampal neurons while sparing nearby hippocampal dentate gyrus (DG) neurons. Lack of consideration of the role of astrocytes is thought to be a factor in the failure o many potential stroke therapies aimed only at neuronal survival (Nedergaard and Dirnagl, 2005). In the prior funding period we demonstrated selective dysfunction of hippocampal CA1 astrocytes at early reperfusion times, long before CA1 neuron death. We published the first demonstration that potent protection of CA1 neurons can be achieved by targeting protective proteins selectively to hippocampal astrocytes. Although delayed CA1 neuronal death after transient ischemia is apoptotic, the regulation of the critically important BCL2 family following cerebral ischemia is not well understood. BCL2 family proteins are central regulators of the life/death decision in cells (Adams et al, 2007), and via their regulation of mitochondrial membrane integrity and function control apoptosis signaling. MicroRNAs (miRNAs) are a novel, abundant class of ~22-nucleotide RNAs that control gene expression post- transcriptionally. Although hundreds of miRNAs have been cloned, little is known about their real targets and functions. Numerous miRNAs are expressed in a cell-specific manner and the miR-29 family has been suggested to be astrocyte related (Smirnova et al, 2005). In this proposal we will investigate the role of miR-29 in brain ischemia and neuroprotection, evaluate manipulation of miR-29 as a novel target for neuroprotection, and assess potential targets of miR-29 in the BCL2 family. Using computational miRNA target prediction algorithms we found that miR-29 could potentially target messenger RNAs of several BCL2 family members, both pro- and anti-apoptotic. Aims 1 and 2 focus on the role of miR-29 in ischemic brain injury. We will first investigate how altering miR-29 expression changes ischemia-induced cell death in vivo and in vitro. Aim 2 will determine changes in miR-29 family member levels in response to ischemia, including cell type and hippocampal region specific changes with forebrain ischemia. We will then address the mechanisms of the miR-29 effects on cells focusing on mitochondrial function and oxidative stress. The role of miR-29 in selective CA1 astrocyte dysfunction will be tested. In addition to focusing on the role of miR-29 in outcome from injury, we need to investigate downstream targets. In Aim 3 we focus on 5 likely miR-29 targets, all members of the BCL2 family, focusing especially on pro-apoptotic PUMA. These are likely candidates for effects of miR-29 on mitochondrial function and oxidative stress. Overall this proposal will test the hypothesis that specific microRNAs are a novel and effective target for protection from ischemic brain injury, as well as advancing our understanding of the contributions of astrocyte regulation and impairment to neurological outcome following cardiac arrest and resuscitation. PUBLIC HEALTH RELEVANCE: Cardiac arrest and resuscitation affects about 450,000 patients/year and currently has few treatment options to reduce the devastating neurological complications that often occur. This research is focused on developing novel ways to rapidly change gene expression to protect the brain and improve neurological outcome. This new treatment can be used to target individual cell types that are affected, and might be able to translate rapidly to clinical applications.

描述（由申请人提供）：心脏骤停幸存者中最担心的残疾之一是神经系统障碍。即使是简短的全球脑缺血，也会导致CA1海马神经元的损失延迟，同时在附近的海马齿状回（DG）神经元附近。缺乏对星形胶质细胞作用的考虑被认为是仅针对神经元存活的许多潜在中风疗法的因素（Nedergaard和Dirnagl，2005年）。在先前的资金期间，我们证明了在早期再灌注时（CA1神经元死亡）早期再灌注时，海马CA1星形胶质细胞的选择性功能障碍。我们发表了第一次演示，即可以通过选择性地将保护蛋白靶向海马星形胶质细胞来实现CA1神经元的有效保护。尽管短暂性缺血后延迟的CA1神经元死亡凋亡是凋亡，但对脑缺血后至关重要的BCL2家族的调节尚不清楚。 Bcl2家族蛋白是细胞生死决策的中心调节剂（Adams等，2007），并通过其对线粒体膜完整性的调节和功能控制凋亡信号传导。 microRNA（miRNA）是一种新颖的，丰富的〜22-核苷酸RNA，可在转录后控制基因表达。尽管已经克隆了数百个miRNA，但对它们的实际目标和功能知之甚少。许多miRNA以细胞特异性方式表达，并建议miR-29家族与星形胶质细胞相关（Smirnova等，2005）。在此提案中，我们将研究miR-29在脑缺血和神经保护中的作用，评估miR-29作为神经保护的新靶标，并评估MiR-29在BCL2家族中的潜在靶标。使用计算miRNA目标预测算法，我们发现miR-29可能会靶向几个BCL2家族成员的Messenger RNA。目标1和2关注miR-29在缺血性脑损伤中的作用。我们将首先研究MIR-29表达的改变如何改变缺血诱导的体内和体外细胞死亡。 AIM 2将确定MiR-29家族成员水平的变化，响应缺血，包括细胞类型和海马区域特异性变化，而前脑缺血。然后，我们将解决miR-29对关注线粒体功能和氧化应激的细胞的作用。将测试miR-29在选择性CA1星形胶质细胞功能障碍中的作用。除了关注miR-29在受伤结果中的作用外，我们还需要研究下游目标。在AIM 3中，我们专注于5个可能的miR-29目标，即BCL2家族的所有成员，尤其是促凋亡PUMA。这些可能是miR-29对线粒体功能和氧化应激的影响的候选者。总体而言，该提案将检验以下假设：特定的microRNA是保护缺血性脑损伤的新颖有效的靶标，并促进了我们对心脏骤停和复苏后星形胶质细胞调节和对神经系统损害的贡献的理解。公共卫生相关性：心脏骤停和复苏会影响约450,000名患者，目前几乎没有治疗选择来减少经常发生的毁灭性神经系统并发症。这项研究的重点是开发新的方法来快速改变基因表达以保护大脑并改善神经系统结果。这种新的治疗方法可用于针对受影响的单个细胞类型，并且可能能够迅速转化为临床应用。