Dissecting functional subgroups and closed-loop circuits between the pedunculopontine nucleus and the basal ganglia

解剖桥脚核和基底神经节之间的功能亚组和闭环回路

• 批准号: 10677467
• 负责人: Michel Fallah
• 金额: $ 3.5万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-01 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10677467
• 关键词: Address; Adult; Anatomy; Axon; Back; Basal Ganglia; Brain region; Calcium; Cell Nucleus; Cells; Communication; Data; Deep Brain Stimulation; Differentiation Antigens; Disease model; Dissection; Electrophysiology (science); Extracellular Matrix Proteins; Feedback; Gait; Ganglia; Genetic; Globus Pallidus; Glutamates; Heterogeneity; Image; Immunohistochemistry; Impairment; Knowledge; Label; Lesion; Maps; Membrane Potentials; Midbrain structure; Mission; Modeling; Molecular; Motor; Motor Pathways; Motor output; Movement; Mus; Nerve Degeneration; Neurons; Optics; Outcome; Output; Parkinson Disease; Pathway interactions; Patients; Pattern; Posture; Property; Proteins; Rest Tremor; Rodent; Rodent Model; Role; Sensory; Severities; Severity of illness; Signal Transduction; Structure; Subgroup; Substantia nigra structure; Synapses; Testing; Thalamic Nuclei; United States National Institutes of Health; behavioral outcome; cholinergic; cholinergic neuron; clinically relevant; confocal imaging; differential expression; dopaminergic neuron; experimental study; improved; interest; molecular marker; motor deficit; motor disorder; motor impairment; nephronectin; neural circuit; new therapeutic target; optogenetics; patch clamp; pharmacologic; postsynaptic; posture instability; protein expression; response; selective expression; tool

Abstract The pedunculopontine nucleus (PPN) interacts with the basal ganglia to enable smooth movement and is a target for deep brain stimulation (DBS) in Parkinson's disease (PD). PD is the most common neurodegenerative motor disorder, characterized by resting tremor, rigidity, slow movement, and postural instability. Caudal-targeted DBS stimulation improves gait impairment in both patients and rodent PD models whereas rostral-targeted DBS worsens it in rodent PD models. Effective PPN-targeted DBS may be attributed to increasing alpha oscillations in the caudal PPN generated by closed-loop circuits and increasing neuronal activity across the PPN. Contradictory outcomes of PPN-targeted DBS in both patients and rodent models suggest functional heterogeneity within the PPN and differences between its rostral and caudal subregions. To understand how DBS differentially modulates movement within the PPN, it is critical to dissect the functional subpopulations within the PPN and determine how they communicate with the basal ganglia. In this proposal, I focus on the cholinergic PPN neurons whose selective degeneration in PD also correlates with gait impairment. I will use ex vivo whole-cell patch clamp electrophysiology, optogenetics, calcium imaging, and retro bead labeling (1) to characterize the intrinsic electrophysiological properties and identify a molecular marker that differentiates rostral and caudal cholinergic PPN neurons in adult mice, (2) to characterize and comprehensively map the regional connectivity of inhibitory synaptic inputs to the PPN, and (3) to identify closed-loop circuits between the inhibitory basal ganglia nuclei and the PPN. Our preliminary data show that the two major inhibitory basal ganglia nuclei, the substantia nigra pars reticulata (SNr) and globus pallidus externus (GPe), differentially project to the rostral and caudal PPN in axon imaging. Using optogenetics with whole cell patch clamp and calcium imaging, we can confirm the functional connectivity of these anatomical axonal projections and characterize inhibitory currents from the SNr and GPe on the PPN. Using immunostaining, I will test the differential expression of five proteins selectively expressed in the PPN compared to other brain regions to identify a molecular marker that can be used as a tool to genetically access the rostral and caudal PPN. Using optogenetics and retrobead-labeling, I will determine whether SNr- and GPe-projecting PPN neurons also receive inhibitory input from the respective basal ganglia nuclei, forming a closed-loop circuit. This proposal will comprehensively characterize and map the regional connectivity of the SNr and GPe to the cholinergic PPN and identify closed-loop circuits that can help us understand how the PPN interacts with the basal ganglia to modulate movement and how its degeneration underlies motor deficits in PD. These findings will guide new pharmacological targets and DBS-targeting of the PPN circuit in PD patients.

抽象的 花梗核核（PPN）与基底神经节相互作用，使运动能够平滑运动，并且是一个 帕金森氏病（PD）中深脑刺激（DBS）的靶标。 PD是最常见的 神经退行性运动障碍，其特征是静止震颤，僵化，运动缓慢和姿势 不稳定。尾靶DBS刺激可改善患者和啮齿动物PD模型的步态障碍 而靶向恒定的DBS在啮齿动物的PD模型中使其恶化。有效的PPN靶向DB可能归因于 增加闭环电路产生的尾状PPN的α振荡并增加了神经元 跨PPN的活动。患者和啮齿动物模型中PPN靶向DBS的矛盾结果 建议在PPN内的功能异质性及其尾部和尾端区域之间的差异。到 了解DBS如何差异调节PPN内的运动，剖析功能至关重要 PPN内的亚群，并确定它们如何与基底神经节通信。在这个建议中，我 专注于胆碱能PPN神经元，其在PD中的选择性变性也与步态相关 损害。我将使用离体全细胞贴片夹电生理学，光遗传学，钙成像和 复古珠标记（1）以表征内在的电生理特性并识别分子 在成年小鼠中区分鼻链和尾胆碱能PPN神经元的标记，（2）表征和 全面绘制抑制性突触输入的区域连通性与PPN，（3）识别 抑制性基底神经节核与PPN之间的闭环电路。我们的初步数据表明 两个主要的抑制性基底神经节核，黑质nigra pars enticulata（SNR）和Globus pallidus Externus（GPE），在轴突成像中差异地投射到尾部和尾骨PPN。与光遗传学一起使用 全细胞斑块夹和钙成像，我们可以确认这些解剖学的功能连通性 轴突投影并表征PPN上SNR和GPE的抑制电流。使用 免疫染色，我将在PPN中选择性地测试五种蛋白的差异表达 与其他大脑区域相比，可以识别可以用作基因访问工具的分子标记物 尾the和尾ppn。使用光遗传学和后磁标记，我将确定SNR-和SNR和 GPE投射PPN神经元也从相应的基底神经节核中接收抑制性输入，形成A 闭环电路。该建议将全面表征并映射 SNR和GPE到胆碱能PPN并确定可以帮助我们了解PPN的闭环电路 与基底神经节相互作用以调节运动以及其退化如何构成运动不足 PD。这些发现将指导PD中PPN电路的新药理目标和DBS靶向 患者。