Adult Neurogenesis and Stroke Recovery

成人神经发生和中风恢复

• 批准号: 8978329
• 负责人: Jack M Parent
• 金额: --
• 依托单位: VETERANS HEALTH ADMINISTRATION
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8978329
• 关键词: Address; Adult; Alleles; Animals; Apoptosis; Area; BCL2 gene; Behavioral; Biological Assay; Brain; Cells; Conflict (Psychology); Corpus striatum structure; Data; Disease; Ganciclovir; Generations; Genetic; Goals; Histologic; Image; In Vitro; Infarction; Injury; Ischemia; Knockout Mice; Label; Lead; Methods; Middle Cerebral Artery Occlusion; Modeling; Motor Skills; Mus; Neurons; Pathway interactions; Phenotype; Population; Process; Proliferating; Prosencephalon; Proteins; Recovery; Recovery of Function; Reporter; Research; Simplexvirus; Site; Slice; Stroke; Synapses; Synaptophysin; Tamoxifen; Techniques; Testing; Thymidine Kinase; Transgenic Mice; Transgenic Organisms; Traumatic Brain Injury; Veterans; abstracting; adult neurogenesis; brain circuitry; brain repair; burden of illness; cell determination; clinically relevant; disability; genetic approach; improved; injured; innovation; mortality; mouse model; nerve stem cell; nervous system disorder; nestin protein; neuroblast; neurogenesis; neuronal replacement; newborn neuron; novel; pro-apoptotic protein; progenitor; promoter; public health relevance; recombinase; regenerative; regenerative therapy; repaired; research study; stroke recovery; stroke therapy; subventricular zone; suicide gene; tool

DESCRIPTION (provided by applicant): Abstract Objectives: The overall goal of this proposal is to determine the importance of adult neurogenesis to the recovery process following stroke. Adult-born neurons are a potential substrate for repair after focal ischemic injury, and it is well established that neural stem cells (NSCs) proliferate and their progeny migrate to sites of injury after experimental stroke. Accumulating evidence indicates that large numbers of adult-generated neurons migrate to the injured striatum and cortex following stroke, but few of these neurons integrate and survive for prolonged periods. Data are conflicting, moreover, as to the phenotypes of the neurons that do survive and the extent to which they integrate into brain circuitry. Determination of cell fate or functional integration is difficult because the tools used to label these cells have been limited. Research Plan: In the proposed studies, innovative transgenic mouse models and retroviral techniques will be used to specifically label or ablate adult-generated neurons in the setting of experimental stroke. In addition, our preliminary data from a Bax knockout mouse line defective in a critical programmed cell death pathway for adult NSCs suggest that more newborn neurons survive after excitotoxic striatal injury in these mice. Using these genetic approaches, we will test our central hypothesis that adult-generated neurons contribute to repair after focal ischemia via neuronal replacement; moreover, inhibiting this process will be detrimental to stroke recovery and, conversely, stimulating the survival of adult NSC progeny will improve recovery. Studies in Specific Aim 1 will characterize the long-term survival, phenotypes and integration of adult-born neurons after focal ischemic injury. Experiments in Specific Aim 2 will determine if adult neurogenesis is critical to the repair process by ablating newly dividing cells following stroke. In Aim 3, we will use conditional Bax null mice to examine whether loss of the pro-apoptotic protein Bax selectively in adult-generated neurons leads to their increased survival and integration, and improved functional recovery after focal ischemic injury. Methods: We will use the transient middle cerebral artery occlusion model in adult mice. Aim 1 will be accomplished by using retroviral labeling of dividing cells and conditional transgenic NSC reporter mice to track the fate of adult-generated neurons. In Aim 2, we will ablate adult-generated neurons using a conditional transgenic mouse model that expresses a pharmacologically activated suicide gene selectively in NSCs. The methods for Aim 3 will involve crossing a neuroblast-specific cre driver mouse line (doublecortin-CreERT2) with a floxed Bax line to delete Bax in neuronal precursors generated after stroke. For Aims 2 and 3, we will determine the influence of experimental manipulations on infarct size histologically, and animals will be behaviorally tested to determine if suppressing neurogenesis impairs or stimulating neurogenesis improves, respectively, motor skill recovery after focal ischemic injury. Clinical Relevance: No regenerative therapies exist for stroke. Progress in these aims will increase our understanding of reparative processes in the brain following focal ischemic injury and offers the potential to contribute to novel regenerative therapies for stroke, a disorder that leads to a substantial disease burden in the Veteran population.

描述（由申请人提供）： 摘要目的：该提案的总体目标是确定成人神经发生对中风后恢复过程的重要性。成年神经元是局灶性缺血损伤后修复的潜在基质，并且众所周知，神经干细胞 实验性中风后，神经干细胞（NSC）增殖，其后代迁移到损伤部位。越来越多的证据表明，中风后，大量成人产生的神经元迁移到受损的纹状体和皮质，但这些神经元很少整合并长期存活。此外，关于存活下来的神经元的表型以及它们融入大脑回路的程度，数据是相互矛盾的。确定细胞命运或功能整合很困难，因为用于标记这些细胞的工具有限。 研究计划：在拟议的研究中，创新的转基因小鼠模型和逆转录病毒技术将用于在实验性中风的情况下特异性标记或消融成人生成的神经元。此外，我们从成年 NSC 的关键程序性细胞死亡途径有缺陷的 Bax 敲除小鼠系中获得的初步数据表明，这些小鼠在兴奋性毒性纹状体损伤后有更多的新生神经元存活。使用这些遗传方法，我们将测试我们的中心假设，即成人生成的神经元通过神经元替换有助于局灶性缺血后的修复；此外，抑制这一过程将不利于中风恢复，相反，刺激成年 NSC 后代的存活将改善恢复。具体目标 1 的研究将描述局灶性缺血性损伤后成年神经元的长期存活、表型和整合。具体目标 2 中的实验将通过消除中风后新分裂的细胞来确定成人神经发生是否对修复过程至关重要。在目标 3 中，我们将使用条件 Bax 缺失小鼠来检查成年神经元中促凋亡蛋白 Bax 的选择性缺失是否会导致其存活率和整合度增加，并改善局灶性缺血性损伤后的功能恢复。 方法：我们将在成年小鼠中使用暂时性大脑中动脉闭塞模型。目标 1 将通过使用分裂细胞的逆转录病毒标记和条件转基因 NSC 报告小鼠来追踪成年神经元的命运来实现。在目标 2 中，我们将使用条件转基因小鼠模型消融成人产生的神经元，该模型在 NSC 中选择性表达药理激活的自杀基因。目标 3 的方法将涉及将神经母细胞特异性 cre 驱动小鼠系 (doublecortin-CreERT2) 与 floxed Bax 系杂交，以删除中风后产生的神经元前体中的 Bax。对于目标 2 和 3，我们将从组织学角度确定实验操作对梗死面积的影响，并对动物进行行为测试，以确定抑制神经发生是否会分别损害或刺激神经发生改善局灶性缺血性损伤后的运动技能恢复。 临床相关性：尚无针对中风的再生疗法。这些目标的进展将增加我们对局灶性缺血性损伤后大脑修复过程的理解，并有可能为中风的新型再生疗法做出贡献，中风是一种给退伍军人群体带来巨大疾病负担的疾病。