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）： 抽象目标：该提案的总体目标是确定成年神经发生在中风后恢复过程中的重要性。成年神经元是局灶性缺血性损伤后修复的潜在底物，并且已经很好地确定神经干细胞 （NSC）增殖，其后代在实验中风后迁移到受伤部位。积累的证据表明，中风后大量成人产生的神经元迁移到受伤的纹状体和皮层，但这些神经元中很少有整合并生存长时间。此外，关于确实存在的神经元的表型以及它们整合到脑电路中的程度是矛盾的。细胞命运或功能整合的确定很困难，因为用于标记这些细胞的工具受到限制。 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地标记或消融成人生成的神经元。此外，我们来自Bax敲除小鼠系的初步数据在成年NSC的关键程序性细胞死亡途径中有缺陷，这表明这些小鼠兴奋性毒性纹状体损伤后，更多的新生神经元在这些小鼠的兴奋性神经元中生存。使用这些遗传方法，我们将测试我们的中心假设，即成年产生的神经元通过神经元替代后有助于修复。此外，抑制这一过程将不利于中风恢复，相反，刺激成人NSC后代的存活将改善恢复。特定目标1的研究将表征局灶性缺血性损伤后成人神经元的长期生存，表型和整合。特定目标2中的实验将确定成年神经发生在中风后消融新分裂的细胞是否对修复过程至关重要。在AIM 3中，我们将使用条件Bax无效小鼠检查成人生成的神经元中促凋亡蛋白BAX的丧失是否会导致其生存率和整合增加，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瞬时脑动脉闭塞模型。 AIM 1将通过使用分裂细胞和条件转基因NSC报告小鼠的逆转录病毒标记来跟踪成人生成的神经元的命运。在AIM 2中，我们将使用条件转基因小鼠模型在NSC中选择性地表达药理学活化的自杀基因。 AIM 3的方法将涉及跨越神经细胞特异性的CRE驱动小鼠系（Doublecortin-Creert2），并用floxed Bax系列删除中风后产生的神经元前体中的BAX。对于目标2和3，我们将确定实验操作对梗塞大小的组织学的影响，并将在行为上测试动物，以确定抑制神经发生是否会损害或刺激神经发生，分别改善了局灶性缺血性损伤后运动技能恢复。 临床相关性：中风不存在再生疗法。这些目标的进展将增加我们对局灶性缺血性损伤后大脑中的修复过程的理解，并为中风的新再生疗法做出贡献，这种疾病会导致退伍军人人群的实质性疾病负担。