Accelerated depletion of hippocampal neural stem cells in neurological disease

神经系统疾病中海马神经干细胞的加速消耗

• 批准号: 9222062
• 负责人: JEANNIE CHIN
• 金额: $ 39.26万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-15 至 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9222062
• 关键词: Acute; Adult; Affect; Age; Age-Months; Alzheimer' s Disease; Alzheimer' s disease model; Amyloid beta-Protein Precursor; Antiepileptic Agents; Anxiety; Appearance; Astrocytes; Behavioral; Brain; Cell division; Cell model; Characteristics; Chronic; Clinical; Cognition; Cognitive; Cognitive deficits; Coupled; Data; Disease; Epilepsy; Exhibits; Functional disorder; Goals; Hippocampus (Brain); Human; Human Amyloid Precursor Protein; Impact Seizures; Impaired cognition; Impairment; Incidence; Injectable; Kainic Acid; Learning; Levetiracetam; Light; Memory; Mental Depression; Modeling; Moods; Mouse Protein; Mus; Neurobehavioral Manifestations; Neurons; Pathologic; Patients; Performance; Pharmacology; Play; Population; Process; Recurrence; Regulation; Rodent; Role; Seizures; Series; Stem cells; Testing; Therapeutic; Time; Transgenic Mice; Wild Type Mouse; adult neurogenesis; age related; cognitive function; dentate gyrus; experimental study; improved; kainate; mouse model; nerve stem cell; nervous system disorder; neurogenesis; newborn neuron; novel; premature; prevent; psychiatric symptom; public health relevance; self-renewal; therapy design

DESCRIPTION (provided by applicant): Adult-born neurons in the dentate gyrus (DG) play critical roles in learning, memory, depression, and anxiety. Both Alzheimer's disease (AD) and epilepsy are associated with marked alterations in neurogenesis, which may contribute to cognitive and psychiatric symptoms that are key features of both diseases. Recurrent seizures, which are characteristic of both AD and epilepsy, may critical in the (dys)-regulation of neurogenesis and downstream cognitive impairments. Acute seizure activity stimulates neurogenesis in rodents and humans, but chronic epilepsy is associated with decreased neurogenesis. Why acute and chronic seizures are associated with opposing effects on neurogenesis, and how this affects cognition, is unknown. Recent findings that neural stem cells in the mouse DG are "disposable" rather than self-renewing may provide an explanation. Upon exiting the quiescent state, these adult DG neural stem cells undergo a series of asymmetric divisions to produce dividing progeny destined to become neurons, and then terminally differentiate into astrocytes. This "disposable stem cell" model accounts for the age-related disappearance of DG neural stem cells, appearance of new astrocytes, and age-related decline in neurogenesis. Such a model would predict that the robust increases in neurogenesis triggered by acute seizures accelerate division-coupled depletion of the neural stem cell pool, leading to reduced neurogenic potential in conditions with recurrent seizures such as AD and epilepsy. Our preliminary data support the hypothesis that loss of DG neural stem cells is accelerated in transgenic mice expressing human amyloid precursor protein (APP), a well-characterized model of AD with spontaneous seizures, and that accelerated loss affects specific cognitive functions that are regulated by adult- born DG neurons. We found similar results in the kainate model of epilepsy; moreover, treatment of APP mice with an anti-epileptic drug appeared to delay the rate of loss, supporting a role for seizures. Building on these preliminary studies, in Aim 1, we will establish that the DG neural stem cell pool undergoes accelerated division-coupled depletion that is commensurate with seizure activity and cognitive deficits in APP mice; in Aim 2 we will determine whether treatment with an anti-epileptic drug prevents depletion of the DG neural stem cell pool and ameliorates performance on a DG-dependent behavioral task; in Aim 3 we will assess whether pharmacologically-induced seizures in wild-type mice also induce division-coupled depletion of the DG neural stem cell pool and deficits in DG function. Determining if seizures accelerate division-coupled depletion of the DG neural stem cell pool will shed new light on understanding the processes that drive both normal use, and pathological depletion, of neural stem cells. The answer will have a major impact on determining the stages of neurogenesis that are most advantageous to focus on for therapeutic strategies. This is an essential step in achieving two major long-term goals: 1) prevent pathological effects of conditions that impact neurogenesis, 2) harness the power of neurogenesis as a treatment for devastating conditions like AD and epilepsy.

描述(申请人提供)：成年出生的神经元齿状回(DG)在学习、记忆、抑郁和焦虑中发挥关键作用。阿尔茨海默病(AD)和癫痫都与神经发生的显著变化有关，这可能导致认知和精神症状，这是这两种疾病的关键特征。反复发作是阿尔茨海默病和癫痫的特征，可能在神经发生和下游认知损害的(Dys)调节中起关键作用。在啮齿动物和人类中，急性癫痫活动刺激神经发生，但慢性癫痫与神经发生减少有关。为什么急性和慢性癫痫发作与神经发生的相反影响相关，以及这如何影响认知，目前尚不清楚。最近的研究发现，小鼠DG中的神经干细胞是“一次性的”，而不是自我更新的，这可能提供了一个解释。在退出静止状态后，这些成年DG神经干细胞经历一系列不对称分裂，产生分裂的后代，最终成为神经元，然后最终分化为星形胶质细胞。这种“一次性干细胞”模型解释了与年龄相关的DG神经干细胞的消失、新的星形胶质细胞的出现以及与年龄相关的神经发生功能的下降。这样的模型将预测，由急性癫痫发作引发的神经发生的强劲增长加速了神经干细胞库的分裂耦合耗竭，导致在反复发作的情况下，如AD和癫痫，神经发生潜力降低。我们的初步数据支持这样的假设，即在表达人淀粉样前体蛋白(APP)的转基因小鼠中，DG神经干细胞的丢失加速，并且加速丢失影响由成年出生的DG神经元调节的特定认知功能。APP是一种具有自发性癫痫的AD模型。我们在红藻氨酸癫痫模型中发现了类似的结果；此外，用抗癫痫药物治疗APP小鼠似乎延缓了丢失率，支持了癫痫发作的作用。在这些初步研究的基础上，在目标1中，我们将确定DG神经干细胞库经历与APP小鼠的癫痫活动和认知缺陷相称的加速分裂耦合耗竭；在目标2中，我们将确定抗癫痫药物的治疗是否防止DG神经干细胞库的耗竭并改善DG依赖行为任务的表现；在目标3中，我们将评估野生型小鼠药物诱导的癫痫发作是否也导致DG神经干细胞库的分裂耦合耗竭和DG功能缺陷。确定癫痫发作是否加速了DG神经干细胞库的分裂偶联耗竭，这将为理解驱动神经干细胞正常使用和病理性耗竭的过程提供新的线索。答案将对确定最有利于治疗策略的神经发生阶段产生重大影响。这是实现两个主要长期目标的关键一步：1)防止影响神经发生的疾病的病理效应；2)利用神经发生的力量作为治疗阿尔茨海默病和癫痫等破坏性疾病的方法。