Function and Regulation of ALDH1A1-positive Nigrostriatal Dopaminergic Neurons in Motor Control and Parkinson's disease

ALDH1A1 阳性黑质纹状体多巴胺能神经元在运动控制和帕金森病中的功能和调节

• 批准号: 10688870
• 负责人: Huaibin Cai
• 金额: $ 191.06万
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10688870
• 关键词: Area; Axon; Behavior; Behavior Control; Behavioral; Brain; Calcium; Calcium Signaling; Chemicals; Chloride Channels; Corpus striatum structure; Cues; Dopamine; Dorsal; Etiology; Failure; Feedback; Fiber Optics; GABA-B Receptor; Glutamates; Head; Image; Impairment; Implant; Knock-in Mouse; Lead; Learning; Light; Maps; Mediating; Memory; Methods; Molecular; Motivation; Motor; Motor Skills; Movement; Mus; NMDA receptor A1; Neurons; Outcome; Parkinson Disease; Pathogenesis; Patients; Pattern; Performance; Physiological; Population; Process; Regulation; Research; Resolution; Rewards; Role; Rotarod Performance Test; Sensory; Signal Transduction; Silicones; Slice; Source; Speed; Substantia nigra structure; Task Performances; Time; Viral Vector; Walking; aldehyde dehydrogenases; cytotoxic; designer receptors exclusively activated by designer drugs; dopaminergic neuron; experimental study; genetic manipulation; in vivo; insight; light gated; motor control; motor learning; motor skill learning; neuronal cell body; optogenetics; presynaptic; receptor; response; sample fixation; selective expression; temporal measurement; treadmill; two-photon; virtual

To reveal the activity pattern of ALDH1A1+ DANs during motor skill learning and sensorimotor behavioral control, we will record single-unit spiking activity from DANs in the ventral SNc of Aldh1a1CreERT2 mice, using optotrode equipped with either silicone laminar arrays or microwire bundles in an adaptive motor learning task, as head-fixed mice learn to walk on a spheric treadmill with head fixation. After learning the motor skill of adaptive walk, mice will proceed to a sensorimotor operant task of virtual navigation on the treadmill with precise sensory cues and feedback to forage for reward. Identification of ALDH1A1+ DANs during recording will be accomplished using the optogenetic tagging method. We will determine how activity of ALDH1A1+ and ALDH1A1-negative (ALDH1A1) DANs is modulated at different epochs and stages of motor learning. We will also investigate burst activity related to the classic reward prediction errors in these neurons in the presence of predictive sensory cues and various trial outcomes. The results will allow us to determine how DAN activity from molecularly defined classes contribute to motor learning and behavioral control. We would expect both burst and tonic activity of ALDH1A1+ DANs to show elevated spike rate during learning which correlates with behavioral improvement. We also expect ALDH1A1+ DANs display unique pause and rebound firing following transient inhibition from striatal inputs that could be essential for learning to avoid negative outcomes and motor errors. Recording spiking activity has the advantage of high temporal resolution when instantaneous timing of spikes is needed to convey critical behavioral information, such as spike timing in DAN bursts to track behavioral epochs. An alternative method for recording DAN activity is using our recently acquired deep brain calcium two-photon imaging, which also allows us to investigate plasticity of DANs in learning by following the activity of the same ALDH1A1+ DAN ensemble over the entire course of learning. The capacity of subcellular spatial resolution in imaging could also help to identify sources of learning related signals to these neurons by visualizing changes in specific input strength in dendritic compartments during learning and task performance. The calcium signals have slower dynamics than spikes, but certain aspects of DAN activity in sub-second scale might be sufficient for behavioral control, such as changes of tonic spike rate or magnitude of their axonal dopamine release. To establish the causality between ALDH1A1+ DAN activity and motor learning performance, we will manipulate somatic spiking activity and axonal dopamine release of ALDH1A1+ DANs with different timescales during the same motor skill and sensorimotor learning tasks described in the recording experiments, using optogenetics and chemogenetics methods. Light-gated chloride channels, such as JAWS, will be expressed in these neurons using Cre-dependent viral vectors to allow transient inhibition of their somatic activity via light delivered through implanted optic fibers in the SNc. Timing of the optogenetic inhibition of soma will be time-locked to specific behavioral epochs to determine how precise temporal patterns of ALDH1A1+ DAN spiking activity, particularly the burst firing, causally contributes to learning. To determine how the longer time scale ALDH1A1+ DAN excitability contribute to learning, facilitatory or inhibitory chemogenetic receptor DREADDs will be expressed in these neurons to allow bidirectional control of their excitability during the task performance. Axonal dopamine release often has region-specific regulation mechanisms independent from somatic spiking. To investigate how dopamine released by these neurons in specific target areas contribute to learning, we will transiently suppress axonal dopamine release of ALDH1A1+ DANs in one of their projected areas. Light activated Gi/ocoupled receptors will be expressed in ALDH1A1+ DAN axons, where their dopamine release can be inhibited by light delivered through an implanted optic fiber at various subregions of the dorsal striatum. The resulting learning efficacy and behavioral changes from all these manipulations will be compared with corresponding sham control mice to draw conclusions. The results will allow us to determine the causal roles of specific aspects of ALDH1A1+ DAN neuronal activity in motor learning and behavioral control. If overall dopamine release resulted from ALDH1A1+ DAN activity over the extended behavioral period contributes to learning, we would expect that reduced excitability of these neurons delays motor learning, while increased excitability could speed the learning. If timing of burst activity of ALDH1A1+ DANs is pivotal in learning, we would expect inhibiting these neurons at the movement initiation causes more motor errors, while inhibiting them at the presence of sensory cues may lead to failure in reward association. Suppression of their dopamine release in the striatum is also expected to impair learning that maybe learning-stage dependent. To gain more circuit insight, an alternative strategy to investigate causal roles of ALDH1A1+ DAN neuronal activity in motor learning is genetically manipulate specific inputs to these neurons. Toward this direction, we had crossbred Aldh1a1CreERT2 mice with Grin1-LoxP KI mice to selectively disrupt the glutamate-mediated excitatory inputs to the ALDH1A1+ DANs. The resulting Grin1 cKO mice performed normally in the rotarod test, suggesting the glutamatergic afferent activity at ALDH1A1+ DANs is not required for the motor skill learning, but may still be involved in other aspects of learning. As the ALDH1A1+ SNc DANs display distinct rebound activity in response to the GABA-B receptor (Gabbr1)-mediated inhibitory inputs from dSPNs, we are in the middle of developing Gabbr1 cKO mice to selectively disrupt the expression of Gabbr1 in ALDH1A1+ DANs. This line of Gabbr1 cKO mice will allow us to critically evaluate the contribution of Gabbr1-mediated rebound and burst activity in ALDH1A1+ DAN-dependent motor skill learning.

为了揭示 ALDH1A1+ DAN 在运动技能学习和感觉运动行为控制过程中的活动模式，我们将使用在自适应运动中配备硅胶层状阵列或微丝束的光极记录 Aldh1a1CreERT2 小鼠腹侧 SNc 中 DAN 的单单元尖峰活动学习任务，头部固定的小鼠学习在头部固定的球形跑步机上行走。在学习了适应性行走的运动技能后，小鼠将在跑步机上进行虚拟导航的感觉运动操作任务，并根据精确的感觉线索和反馈来寻找奖励。记录过程中 ALDH1A1+ DAN 的识别将使用光遗传学标记方法来完成。我们将确定 ALDH1A1+ 和 ALDH1A1-阴性 (ALDH1A1) DAN 的活性如何在运动学习的不同时期和阶段进行调节。我们还将研究在存在预测性感觉线索和各种试验结果的情况下与这些神经元中的经典奖励预测错误相关的突发活动。结果将使我们能够确定分子定义类别的 DAN 活性如何促进运动学习和行为控制。我们预计 ALDH1A1+ DAN 的突发活性和强直活性在学习过程中都会表现出升高的峰值速率，这与行为改善相关。我们还预计 ALDH1A1+ DAN 在纹状体输入短暂抑制后表现出独特的暂停和反弹放电，这对于学习避免负面结果和运动错误可能至关重要。 当需要瞬时尖峰计时来传达关键行为信息时，例如 DAN 突发中的尖峰计时以跟踪行为时期，记录尖峰活动具有高时间分辨率的优势。记录 DAN 活动的另一种方法是使用我们最近获得的深部脑钙双光子成像，这也使我们能够通过在整个学习过程中跟踪相同 ALDH1A1+ DAN 整体的活动来研究 DAN 在学习中的可塑性。成像中的亚细胞空间分辨率能力还可以通过可视化学习和任务执行过程中树突区室中特定输入强度的变化来帮助识别这些神经元的学习相关信号的来源。钙信号的动态比尖峰慢，但亚秒级 DAN 活动的某些方面可能足以进行行为控制，例如强直尖峰速率的变化或其轴突多巴胺释放的幅度。 为了建立 ALDH1A1+ DAN 活动与运动学习表现之间的因果关系，我们将使用光遗传学和化学遗传学方法，在记录实验中描述的相同运动技能和感觉运动学习任务中，以不同的时间尺度操纵 ALDH1A1+ DAN 的体细胞尖峰活动和轴突多巴胺释放。光门控氯离子通道（例如 JAWS）将使用 Cre 依赖性病毒载体在这些神经元中表达，通过植入 SNc 中的光纤传递光来暂时抑制其体细胞活动。体细胞光遗传学抑制的时间将被锁定在特定的行为时期，以确定 ALDH1A1+ DAN 尖峰活动的精确时间模式，特别是突发放电，如何因果地促进学习。为了确定较长时间尺度 ALDH1A1+ DAN 兴奋性如何促进学习，促进或抑制性化学遗传受体 DREADD 将在这些神经元中表达，以允许在任务执行过程中双向控制其兴奋性。轴突多巴胺释放通常具有独立于体细胞尖峰的区域特​​异性调节机制。为了研究这些神经元在特定目标区域释放的多巴胺如何有助于学习，我们将暂时抑制 ALDH1A1+ DAN 在其投影区域之一的轴突多巴胺释放。光激活的 Gi/o 耦合受体将在 ALDH1A1+ DAN 轴突中表达，其中通过植入背侧纹状体各个亚区域的光纤传递的光可以抑制其多巴胺释放。所有这些操作所产生的学习效率和行为变化将与相应的假对照组小鼠进行比较，以得出结论。这些结果将使我们能够确定 ALDH1A1+ DAN 神经元活动的特定方面在运动学习和行为控制中的因果作用。如果在延长的行为期内 ALDH1A1+ DAN 活动导致的总体多巴胺释放有助于学习，我们预计这些神经元的兴奋性降低会延迟运动学习，而兴奋性增加则可以加速学习。如果 ALDH1A1+ DAN 爆发活动的时间对于学习至关重要，我们预计在运动开始时抑制这些神经元会导致更多的运动错误，而在存在感觉提示时抑制它们可能会导致奖励关联失败。抑制纹状体中多巴胺的释放预计也会损害学习能力，这可能与学习阶段有关。 为了获得更多的回路洞察力，研究 ALDH1A1+ DAN 神经元活动在运动学习中的因果作用的另一种策略是通过基因操纵这些神经元的特定输入。朝着这个方向，我们将 Aldh1a1CreERT2 小鼠与 Grin1-LoxP KI 小鼠杂交，以选择性破坏谷氨酸介导的 ALDH1A1+ DAN 的兴奋性输入。由此产生的 Grin1 cKO 小鼠在转棒测试中表现正常，表明 ALDH1A1+ DAN 的谷氨酸传入活动不是运动技能学习所必需的，但仍可能参与学习的其他方面。由于 ALDH1A1+ SNc DAN 对 dSPN 的 GABA-B 受体 (Gabbr1) 介导的抑制输入做出反应，表现出明显的反弹活性，因此我们正在开发 Gabbr1 cKO 小鼠，以选择性破坏 ALDH1A1+ DAN 中 Gabbr1 的表达。该 Gabbr1 cKO 小鼠品系将使我们能够批判性地评估 Gabbr1 介导的反弹和爆发活动在 ALDH1A1+ DAN 依赖性运动技能学习中的贡献。