Functional roles for E2F1 in neurons: mechanisms of synaptic damage in HIV-associ

描述（由申请人提供）：HIV相关神经认知障碍在临床上定义为由进行性神经元损伤引起的运动、认知和行为缺陷的组合。虽然一系列因素有助于发生在HAND中的神经变性，但导致神经元损伤的确切机制仍不清楚。有趣的是，细胞周期机制，特别是E2F1，已涉及许多神经退行性疾病，包括手。然而，这种细胞周期相关蛋白的生理和病理作用仍然知之甚少。最终，这一新知识将导致一种新的治疗策略，即靶向保留E2F1生理功能，同时阻断其病理活性，用于治疗HAND和其他神经退行性疾病。本提案中提供的初步数据表明，E2F1结合RNA并在突触特化中发挥作用，从而导致E2F1通过其在有丝分裂后神经元中的RNA结合活性调节突触特化的特定假设。为了确定E2F1在突触特化中的作用，将使用RNA干扰技术或基因敲除动物耗尽E2F1，并测定树突状分支、棘形态发生、PSD 95聚类和突触数量的变化。为了确定E2F1 RNA结合活性在神经元中的作用，将用缺乏RNA结合结构域或含有RNA竞争性配体的显性负性构建体抑制RNA结合活性，并测定神经元活力、靶配体稳定性和突触特化的变化。这些实验的结果将确定E2F1在有丝分裂后神经元中的生理作用及其在HAND中的潜在病理作用。 公共卫生相关性：HIV相关性痴呆患者表现出细胞周期相关蛋白E2F1表达增加。然而，关于它在神经元中的生理作用和在神经变性中的病理作用知之甚少。我们相信，确定其在神经元中的生理功能将导致靶向E2F1的新的治疗策略，以防止神经元损伤和随后的HIV相关痴呆的认知能力下降。

DESCRIPTION (provided by applicant): HIV-associated neurocognitive disorder is clinically defined by a combination of motor, cognitive, and behavioral deficits that result from progressive neuronal damage. Although a constellation of factors contributes to the neurodegeneration that occurs in HAND, the precise mechanism leading to neuronal damage remains unelucidated. Interestingly, the cell cycle machinery, specifically E2F1, has been implicated in many neurodegenerative diseases including HAND. However, both the physiologic and the pathologic roles of this cell cycle-related protein remain poorly understood. Ultimately, this new knowledge will lead to a novel therapeutic strategy of targeting the preservation of E2F1 physiologic function while simultaneously blocking its pathologic activity for treating HAND and other neurodegenerative diseases. The preliminary data provided in this proposal suggests that E2F1 binds RNA and plays a role in synaptic specialization, thus leading to the specific hypothesis of which E2F1 regulates synaptic specialization through its RNA binding activity in postmitotic neurons. To determine the role of E2F1 in synaptic specialization, E2F1 will be depleted using RNA interference technology or genetic knockout animals and assay for changes in dendritic arborization, spine morphogenesis, PSD95 clustering, and synapse number. To determine the role of E2F1 RNA binding activity in neurons, the RNA binding activity will be inhibited with dominant negative constructs lacking RNA binding domain or containing RNA competitive ligand and assay for changes in neuronal viability, stability of target ligands, and synaptic specializations. The results from these experiments will identify the physiologic role of E2F1 in postmitotic neurons and its potential pathologic contributions in HAND. PUBLIC HEALTH RELEVANCE: Patients with HIV-associated dementia exhibit increased expression of cell cycle-related protein E2F1. However, little is known about its physiologic role in neurons and its pathologic role in neurodegeneration. We believe that identifying its physiologic function in neurons will lead to novel therapeutic strategy of targeting E2F1 to prevent neuronal damage and subsequent cognitive decline in HIV-associated dementia.