Optogenetic Approaches to Functional Recovery After Stroke

描述（由申请人提供）：中风是一种严重的急性神经损伤，破坏脑功能并导致神经元死亡。在美国，每年约有80万人受到中风的影响，大多数幸存者往往生活在长期残疾中。功能 中风后可以恢复，这种恢复归因于大脑重塑和神经可塑性，即大脑修复和重建神经元之间的连接。脑刺激技术，如电刺激或经颅磁刺激已用于动物和人类，以提高中风后的恢复。然而，所涉及的神经回路和介导这种恢复的机制还不清楚。此外，这些刺激技术非特异性地刺激刺激部位附近的所有细胞类型，导致不期望的副作用。在这项提案中，我们将使用光遗传学方法来特异性刺激中风后的神经元，并研究对功能恢复的影响及其潜在机制。光遗传学是一种新的策略，利用光敏藻类蛋白，如视紫红质（ChR 2），以快速和精确的方式操纵大脑中特定细胞群的兴奋性。光遗传刺激可以增加神经元的兴奋性，可能导致神经营养因子的释放、轴突喷射/突触发生的增强和脑血流量的增加，所有这些对于中风后的功能恢复都很重要。因此，我们假设初级运动皮层（M1）神经元的光遗传学刺激可以增强内源性修复/可塑性机制，促进中风后的恢复。我们将使用在神经元启动子下表达ChR 2的转基因小鼠系来验证我们的假设。我们的初步数据表明，对小鼠同侧初级运动皮层中的神经元进行光遗传学刺激可改善其中风后的行为恢复。在目标1中，我们将使用感觉运动行为测试来评估中风后不同脑区域中的光遗传学神经元刺激后的功能恢复。我们将在中风恢复阶段开始刺激，并确定促进中风恢复的最佳脑刺激目标。在Aim 2中，我们将研究驱动这种恢复的潜在机制，包括脑血流量的变化，神经营养因子的释放，轴突发芽和突触发生。我们的研究将促进对卒中后恢复的内源性修复和可塑性机制的理解，并确定促进恢复的最佳脑刺激靶点。了解修复和恢复过程中涉及的蛋白质和过程可能会导致能够促进中风后恢复的治疗药物靶点的新发现。

DESCRIPTION (provided by applicant): Stroke is a major acute neurological insult that disrupts brain function and causes neuron death. Each year about 800,000 people are affected by stroke in the United States, and most survivors often live with long-term disability. Functional recovery can occur after stroke, and this recovery is attributed to brain remodeling and neuroplasticity, when the brain repairs and rebuilds connections between neurons. Brain stimulation techniques such as electrical stimulation or transcranial magnetic stimulation have been used in animals and humans to enhance recovery after stroke. However, the neural circuits involved and the mechanisms mediating this recovery are not well understood. In addition, these stimulation techniques non-specifically stimulate all cell types near the stimulation site, leading to undesired side effects. In this proposal, we will use the optogenetic approach to specifically stimulate neurons after stroke and examine the effects on functional recovery and the underlying mechanisms. Optogenetics is a novel strategy that utilizes light-sensitive algal proteins, such as Channelrhodopsin (ChR2), to manipulate the excitability of specific cell groups in the brain, in a fast and precise manner. Optogenetic stimulation can increase neuronal excitability, potentially leading to release of neurotrophic factors, enhancement of axonal spouting/synaptogenesis and increased cerebral blood flow, all of which are important in functional recovery after stroke. Therefore, we hypothesize that optogenetic stimulation of neurons in the primary motor cortex (M1) can augment endogenous repair/plasticity mechanisms and promote recovery after stroke. We will use a transgenic mouse line expressing ChR2 under a neuronal promoter to test our hypothesis. Our preliminary data show that optogenetic stimulation of neurons in the ipsilesional primary motor cortex of mice improved their behavioral recovery after stroke. In Aim 1, we will use sensorimotor behavior tests to evaluate functional recovery after optogenetic neuronal stimulation in various brain regions after stroke. We will start stimulation during the recovery phase of stroke and determine the most optimal brain stimulation target for promoting stroke recovery. In Aim2, we will investigate the underlying mechanisms that drive this recovery, including changes in cerebral blood flow, release of neurotrophic factors, axonal sprouting and synaptogenesis. Our study will advance the understanding of endogenous repair and plasticity mechanisms underlying recovery after stroke, as well as determine the most optimal brain stimulation target to promote recovery. Understanding the proteins and processes involved during repair and recovery could lead to novel discoveries of therapeutic drug targets able to facilitate recovery after stroke.