Correlation of astrocyte Ca2+ microdomain activity with motor learning and neuronal function

星形胶质细胞 Ca2 微区活性与运动学习和神经元功能的相关性

• 批准号: 9816573
• 负责人: Jennifer Shih
• 金额: $ 6.12万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-10-01 至 2021-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9816573
• 关键词: Affect; Animal Behavior; Animals; Astrocytes; Behavior; Behavioral Paradigm; Brain; Calcium; Calcium Signaling; Cells; Characteristics; Chronic; Coupled; Data; Development; Epilepsy; Functional disorder; Goals; Halorhodopsins; Image; Injections; Knowledge; Learning; Light; Mediating; Membrane; Mental Depression; Morphology; Motor; Motor Cortex; Movement; Mus; Neuroglia; Neurologic; Neurons; Neurotransmitters; Pattern; Performance; Population; Positioning Attribute; Process; Research; Resolution; Schizophrenia; Shapes; Signal Transduction; Stereotyping; Structure; Synapses; Synaptic Transmission; System; Techniques; Testing; Training; Transgenic Mice; Viral; Virus; Work; calcium indicator; classical conditioning; designer receptors exclusively activated by designer drugs; excitatory neuron; experimental study; in vivo; insight; learned behavior; motor learning; nervous system disorder; neuronal circuitry; neuropsychiatric disorder; neurotransmission; novel therapeutics; optogenetics; promoter; receptor; response; spatiotemporal; synaptic function; trial comparing; two-photon

The goal of the proposed research is to understand how astrocytes, a type of glial cell in the brain, work together with motor cortex neurons to mediate motor learning. Previous studies have shown that a stable ensemble of neurons emerges as an animal becomes expert at a stereotyped movement. It has also been shown that astrocyte calcium signaling, particularly in microdomains of the fine processes surrounding synapses, responds to and correlates with neuronal activity. Astrocyte microdomains are considered to reflect synaptic activity and in turn, influence synaptic function. We hypothesize that a stable pattern of motor cortex astrocyte Ca2+ activity in microdomains develops during acquisition of a stereotyped motor movement in mice, is correlated with neuronal activation and learning, and together with intracellular Ca2+, is potentially causal for learning. We will utilize a range of cutting edge techniques to test this hypothesis, as well as a lever push task, which is a motor learning paradigm that features both associative learning and acquisition of a stereotyped motor movement. We will utilize transgenic mice expressing membrane-bound genetically encoded calcium indicators in astrocytes, combined with high-resolution two-photon imaging, to chronically image calcium microdomain activity as the animal learns to perform the task. These experiments will determine whether unique microdomain activation patterns emerge with motor learning. We then propose to optogenetically disrupt neuronal signaling in the motor cortex using expression of light-activated halorhodopsin or channelrhodopsin in excitatory neurons to inactivate or activate neuronal activity, respectively, in order to determine if patterns of astrocyte calcium activity in microdomains are disrupted along with motor learning. Finally, we will disrupt intracellular calcium signaling in astrocytes using designer receptors exclusively activated by designer drugs (DREADDs) to determine whether there is an effect on motor learning when astrocyte calcium signals, including microdomains, are disrupted. Together, these studies will not only identify an astrocyte “signature” encoded by microdomains which is associated with motor learning, but also provide mechanistic insight into how this activity structure is regulated by neuronal activation, and how, alongside intracellular Ca2+ signaling, it influences motor learning. Given that astrocyte dysfunction has been implicated in a number of neurological conditions that involve aberrant neuronal circuit function, including schizophrenia, depression, and epilepsy, advancing our understanding of astrocyte-neuron interactions will fill critical gaps in knowledge and potentially contribute to novel therapeutics.

拟议研究的目标是了解星形胶质细胞（大脑中的一种神经胶质细胞）如何与运动皮层神经元一起工作来介导运动学习。先前的研究表明，当动物成为刻板运动的专家时，就会出现稳定的神经元集合。研究还表明，星形胶质细胞钙信号传导，特别是在突触周围精细突起的微域中，对神经元活动做出反应并与之相关。星形胶质细胞微区被认为反映突触活动，进而影响突触功能。我们假设，在小鼠获得定型运动运动过程中，微区中运动皮层星形胶质细胞 Ca2+ 活性的稳定模式形成，与神经元激活和学习相关，并且与细胞内 Ca2+ 一起，可能是学习的原因。我们将利用一系列尖端技术以及杠杆推动任务来检验这一假设，这是一种运动学习范式，具有联想学习和刻板运动运动的习得功能。我们将利用在星形胶质细胞中表达膜结合基因编码钙指示剂的转基因小鼠，结合高分辨率双光子成像，在动物学习执行任务时对钙微域活动进行长期成像。这些实验将确定运动学习是否会出现独特的微域激活模式。然后，我们建议使用光激活的盐视紫红质或通道视紫红质在兴奋性神经元中的表达来以光遗传学方式破坏运动皮层中的神经元信号传导，以分别失活或激活神经元活动，以确定微域中星形胶质细胞钙活动的模式是否随着运动学习而被破坏。最后，我们将使用专门由设计药物（DREADD）激活的设计受体来破坏星形胶质细胞中的细胞内钙信号传导，以确定当星形胶质细胞钙信号（包括微区）被破坏时是否会对运动学习产生影响。 总之，这些研究不仅将鉴定出与运动学习相关的微结构域编码的星形胶质细胞“特征”，而且还将提供关于这种活动结构如何受神经元激活调节，以及它如何与细胞内 Ca2+ 信号传导一起影响运动学习的机制见解。鉴于星形胶质细胞功能障碍与许多涉及神经元回路功能异常的神经系统疾病有关，包括精神分裂症、抑郁症和癫痫，提高我们对星形胶质细胞-神经元相互作用的理解将填补关键的知识空白，并可能有助于新的治疗方法。