Microglia mediated suppression of dopamine induced neuronal responses and behavior

小胶质细胞介导的多巴胺诱导的神经元反应和行为的抑制

• 批准号: 10294243
• 负责人: Anne Schaefer
• 金额: $ 42.25万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2023-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10294243
• 关键词: Ablation; Address; Adult; Animal Model; Attenuated; Basal Ganglia; Behavior; Binding; Brain; Brain region; Bromodomain; Cell Separation; Cell surface; Cellularity; ChIP-seq; Characteristics; Chromatin; Cognition; Corpus striatum structure; Coupled; Cyclic AMP-Dependent Protein Kinases; Data; Development; Dopamine; Dopamine D1 Receptor; Dopamine D2 Receptor; Feedback; Gene Expression; Gene Expression Profiling; Genes; Genetic; Genetic Models; Genetic Transcription; Goals; Golf; Human; Lead; Mediating; Mediator of activation protein; Mental disorders; Methodology; Microglia; Modeling; Molecular; Moods; Morphology; Motor Activity; Mus; Nature; Neurodevelopmental Disorder; Neurons; Neurotransmitters; Outcome; Play; Population; Procedures; Production; Proteins; RNA; Receptor Activation; Regulation; Regulator Genes; Research Proposals; Rewards; Role; Seizures; Signal Transduction; Synapses; Techniques; Testing; Transgenic Mice; Untranslated RNA; base; behavioral outcome; brain tissue; cell type; dopamine system; experimental study; gene network; gray matter; in vivo; innovation; motor behavior; neuronal survival; novel; novel therapeutic intervention; receptor; regional difference; response; white matter

Project Summary The proposal's objective is to identify the mechanisms that support microglia-mediated suppression of dopamine responses. Microglia contribute to normal brain development by supporting neuronal survival and brain tissue clearance from non-functional neurons and synapses. We identified a novel function of microglia that involves the suppression of dopamine-induced behaviors in the adult brain. We found that mice with a pan-brain or striatum-specific ablation of microglia display exaggerated dopamine- induced motor activity and a propensity to seizures. These findings suggest a suppressive effect of microglia on striatal neuron activation. Our preliminary data suggest that this effect could be elicited directly by dopamine-induced microglia activation. We found that 10-15% of microglia in the striatum but not in other brain regions express the dopamine D1 receptor. The expression of the dopamine D1 receptor by a subpopulation of striatal microglia suggests a potential novel negative feedback mechanism where microglia tune neuronal response to dopamine after directly sensing/responding to changes in the neurotransmitter level. Our proposal aims to elucidate the mechanism underlying microglia-mediated suppression of dopamine responses and revolves around the following major questions: Is there a specific subpopulation of striatal microglia that controls neuronal suppression, and if yes, is it based on direct microglia triggering by dopamine? Does the suppressive activity of microglia target a specific subpopulation of striatal neurons? What is the nature of the microglia-produced mediators that impact neuronal responsiveness to dopamine? Our proposal relies heavily on in vivo animal models, and we plan to generate new strains of transgenic mice that enable the manipulation of microglia in the striatum. One of the innovative methodological aspects of the proposal involves state of the art cell type-specific gene expression analysis in different neurons and microglia populations using techniques developed by us that minimize aberrant changes in gene expression caused by cell isolation procedures. In addition to elucidating the specific striatal microglia and neuron subpopulations mediating the suppressive effect, our proposal aims to identify the microglia-produced regulators of neuronal responses to dopamine. We found that the suppressive activity of microglia requires the expression of the bromodomain-containing protein Brd4, which functions as a regulator of gene transcription. Our data suggest that Brd4-bound microglia genes, especially those that are upregulated by dopamine, may encode microglial suppressors of dopamine responses. Identification of these genes is one of the major goals of the proposal, which we plan to achieve by using microglia-specific RNA and chromatin analysis developed by us. Overall, our proposal has the potential to identify novel microglia- based mechanisms that regulate neuronal responses to dopamine.

项目概要 该提案的目标是确定支持小胶质细胞介导的抑制的机制 多巴胺反应。小胶质细胞通过支持神经元存活来促进正常的大脑发育 以及脑组织从非功能性神经元和突触中的清除。我们发现了一个新功能 小胶质细胞涉及抑制成人大脑中多巴胺诱导的行为。我们发现 具有全脑或纹状体特异性小胶质细胞消融的小鼠表现出过度的多巴胺- 诱发运动活动和癫痫发作倾向。这些发现表明有抑制作用 小胶质细胞对纹状体神经元激活的影响。我们的初步数据表明可以引发这种效应 直接通过多巴胺诱导的小胶质细胞激活。我们发现纹状体中有 10-15% 的小胶质细胞 但在其他大脑区域不表达多巴胺D1受体。多巴胺D1的表达 纹状体小胶质细胞亚群的受体表明潜在的新型负反馈 小胶质细胞在直接感知/响应多巴胺后调节神经元对多巴胺的反应的机制 神经递质水平的变化。我们的建议旨在阐明潜在的机制 小胶质细胞介导的多巴胺反应抑制主要围绕以下几个方面 问题：是否存在控制神经元抑制的特定纹状体小胶质细胞亚群，以及 如果是，它是基于多巴胺直接触发小胶质细胞吗？小胶质细胞有抑制活性吗 针对纹状体神经元的特定亚群？小胶质细胞产生的性质是什么 影响神经元对多巴胺反应的介质？我们的建议很大程度上依赖于体内 动物模型，我们计划培育新的转基因小鼠品系，从而能够操纵 纹状体中的小胶质细胞。该提案的创新方法论方面之一涉及以下方面： 使用不同神经元和小胶质细胞群体的艺术细胞类型特异性基因表达分析 我们开发的技术可最大限度地减少细胞引起的基因表达异常变化 隔离程序。除了阐明特定的纹状体小胶质细胞和神经元亚群 调节抑制作用，我们的建议旨在确定小胶质细胞产生的调节因子 神经元对多巴胺的反应。我们发现小胶质细胞的抑制活性需要 含溴结构域蛋白 Brd4 的表达，该蛋白作为基因的调节因子 转录。我们的数据表明，Brd4 结合的小胶质细胞基因，尤其是那些上调的小胶质细胞基因 通过多巴胺，可能编码多巴胺反应的小胶质细胞抑制因子。这些基因的鉴定 是该提案的主要目标之一，我们计划通过使用小胶质细胞特异性 RNA 来实现 我们开发的染色质分析。总的来说，我们的建议有可能识别新型小胶质细胞 调节神经元对多巴胺反应的机制。