CaMKII, endocannabinoids, synaptic plasticity and motor function

CaMKII、内源性大麻素、突触可塑性和运动功能

基本信息

批准号：
8885927
负责人：
ROGER J COLBRAN
金额：
$ 38.22万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-09-01 至 2016-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8885927
关键词：
2-arachidonylglycerol Ataxia Basal Ganglia Behavior Binding Biological Assay Brain Brain region Ca(2+)-Calmodulin Dependent Protein Kinase Calcium/calmodulin-dependent protein kinase Cells Cerebellum Complex Corpus striatum structure Depressed mood Dopamine Dopamine D2 Receptor Endocannabinoids Enzymes Equilibrium Excitatory Synapse Exhibits Follow-Up Studies Functional disorder Glutamates Goals Health Hippocampus (Brain)Home environment Huntington Disease Hyperactive behavior Knock-in Mouse Learning Link Memory Metabolism Molecular Monitor Motor Motor Activity Motor Cortex Movement Movement Disorders Mus Mutant Strains Mice Mutation Neurons Output Parkinson Disease Pathway interactions Peptides Phosphorylation Phosphorylation Site Physiological Play Property Proteins Regulation Reporter Role Signal Transduction Site Slice Synapses Synaptic plasticity Testing Thalamic structure Tracer Transgenic Organisms base calmodulin-dependent protein kinase II gamma-Aminobutyric Acid in vivo inhibitor/antagonist lipoprotein lipase motor deficit motor learning nervous system disorder new therapeutic target novel postsynaptic selective expression synaptic depression synaptic function tool

项目摘要

DESCRIPTION (provided by applicant): The striatum plays a key role in motor activity/coordination and goal-directed, habitual learning. Normal striatal drive of motor activity requires precisely balanced opposing outputs from two types of striatal medium spiny neurons (MSNs) that express D1- and D2-dopamine(DA) receptors. A complex signaling cross-talk between glutamate and DA in D1- and D2-MSNs involves "on demand" Ca2+-dependent endocannabinoid (eCB) synthesis. Thus, DA, glutamate and eCBs collaborate to balance short- and long-term control of the two striatal output pathways by engaging distinct signaling mechanisms in the two MSN subtypes. Disruption of these mechanisms can induce motor deficits (e.g., Parkinson's Disease) or other abnormal striatal-based behaviors. Ca2+/calmodulin-dependent protein kinase II (CaMKII) has diverse bidirectional roles controlling excitatory synapses in hippocampus, cortex and cerebellum. While CaMKII is expressed in both striatal MSN subtypes, suggesting that it regulates excitatory inputs to striatal MSNs and motor activity, the precise functions of striatal CaMKII are poorly understood. Our analyses of knockin mutant mice with the Thr286 autophosphorylation site in CaMKIIα replaced by Ala (T286A-KI mice) revealed specific roles for CaMKII in long- and short term eCB- dependent control of excitatory inputs to D1- and D2-MSNs. We also found that CaMKIIα associates with and phosphorylates diacylglycerol lipase α (DGLα), the rate-limiting enzyme for Ca2+-dependent synthesis of the most abundant brain eCB, 2-arachidonyl glycerol (2-AG). In addition, baseline hyperactivity of T286A-KI mice can be rescued by inhibiting 2-AG breakdown. These initial findings strongly support a novel hypothesis that CaMKII is a critical link between postsynaptic Ca2+ and the initiation of 2-AG signaling that controls striatal synapses and striatal based-behaviors. We also created novel transgenic eAC3I mice that selectively express a short CaMKII inhibitor peptide fused to eGFP in striatal MSNs. Three specific aims will exploit unique features of T286A-KI and eAC3I mice to test specific hypotheses about the roles of striatal CaMKII autophosphorylation and activity. 1. Test the hypothesis that Ca2+-dependent 2-AG synthesis is modulated by CaMKII. We will identify sites of phosphorylation and CaMKII-binding domains in DGLα. DGLα phosphorylation, DGLα activity and 2-AG synthesis will be investigated in heterologous cells and in striatal slices from WT, T286A-KI and eAC3I mice. 2. Test the hypothesis that CaMKII modulates eCB-dependent synaptic regulation in striatal MSNs. Short and long-term roles of CaMKII will be determined by comparing the properties of excitatory synaptic inputs to D1- and D2-MSNs in striatal slices from WT, T286A-KI and eAC3I mice, and by using CaMKII inhibitor peptides. 3. Test the hypothesis that CaMKII modulates eCB-dependent motor activity. We will evaluate motor activity and coordination under basal conditions and following pharmacological modulation of 2-AG metabolism in WT, T286A-KI and eAC3I mice.

描述（由申请人提供）：纹状体在运动活动/协调和目标导向的习惯性学习中发挥着关键作用。需要精确平衡表达 D1- 和 D2- 多巴胺 (DA) 受体的两种类型纹状体中型多巴胺 (DA) 受体的相反输出，D1- 和 D2-MSN 中谷氨酸和 DA 之间的复杂信号串扰涉及“按需”。 “Ca2+ 依赖性内源性大麻素 (eCB) 合成。因此，DA、谷氨酸和 eCB 通过参与不同的纹状体输出途径来协作平衡两个纹状体输出途径的短期和长期控制。两种 MSN 亚型中的信号传导机制的破坏可引起运动缺陷（例如帕金森病）或其他异常的纹状体行为，Ca2+/钙调蛋白依赖性蛋白激酶 II (CaMKII) 具有控制海马兴奋性突触的多种双向作用。而 CaMKII 在两种纹状体 MSN 亚型中表达，表明它调节兴奋性输入我们对纹状体 MSN 和运动活动的了解甚少，我们对 CaMKIIα 中 Thr286 自磷酸化位点被 Ala 取代的敲入突变小鼠（T286A-KI 小鼠）的分析揭示了 CaMKII 在长期和短期 eCB 中的特定作用。 - 对 D1- 和 D2-MSN 的兴奋性输入的依赖性控制我们还发现 CaMKIIα 与磷酸化相关。二酰基甘油脂肪酶 α (DGLα) 是最丰富的脑 eCB、2-花生四烯酸甘油 (2-AG) 的 Ca2+ 依赖性合成的限速酶。此外，可以通过抑制 2 来挽救 T286A-KI 小鼠的基线过度活跃。 -AG 分解。这些初步发现有力地支持了一项新假设，即 CaMKII 是突触后 Ca2+ 与控制 2-AG 信号传导启动之间的关键环节。我们还创建了新型转基因 eAC3I 小鼠，其在纹状体 MSN 中选择性表达与 eGFP 融合的短 CaMKII 抑制肽，将独特地利用 T286A-KI 和 eAC3I 小鼠的特征来测试有关纹状体突触和纹状体行为的特定假设。纹状体 CaMKII 自磷酸化和活性的作用 1. 检验 Ca2+ 依赖性 2-AG 合成受到调节的假设。我们将在异源细胞和 WT、T286A-KI 和 eAC3I 小鼠的纹状体切片中研究 DGLα 磷酸化和 CaMKII 结合域的位点。 CaMKII 调节纹状体 MSN 中 eCB 依赖性突触调节的假设。 CaMKII 将通过比较 WT、T286A-KI 和 eAC3I 小鼠纹状体切片中 D1- 和 D2-MSN 的兴奋性突触输入特性并使用 CaMKII 抑制剂肽来确定。 3. 检验 CaMKII 调节 eCB 依赖性的假设。我们将评估 WT 中的运动活动和协调基础条件以及 2-AG 代谢的逻辑药物调节， T286A-KI 和 eAC3I 小鼠。