CB2 Cannabinoid Receptors and Cocaine Action: Studies with Conditional Knock Outs

CB2 大麻素受体和可卡因作用：条件敲除研究

• 批准号: 9250114
• 负责人: Cecilia J Hillard
• 金额: $ 19.25万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9250114
• 关键词: Affect; Agonist; Alcohol or Other Drugs use; Antibodies; Behavior; Behavioral; Brain; CNR1 gene; CNR2 gene; Cannabinoids; Cannabis; Cells; Chronic; Cocaine; Corpus striatum structure; Coupled; Data; Detection; FDA approved; Financial compensation; Flow Cytometry; Grant; Immune; Immunohistochemistry; Inflammatory; Innate Immune System; Intake; Intervention; Intravenous; Knock-out; LoxP-flanked allele; Mediating; Microglia; Morphology; Motor Activity; Mus; Neurons; Pharmaceutical Preparations; Pharmacology; Pharmacotherapy; Phenotype; Play; Principal Investigator; Psychopathology; Receptor Activation; Receptor Gene; Receptor Signaling; Reporter; Reporting; Research Personnel; Rewards; Rodent Model; Role; Self Administration; Site; Source; Substance Use Disorder; Synapses; Synaptic plasticity; Testing; Transgenic Mice; Tyrosine 3-Monooxygenase; Ventral Tegmental Area; behavioral response; cannabinoid receptor; cell type; cocaine exposure; cocaine use; cytokine; dopaminergic neuron; effective therapy; emotional abuse; experimental study; inflammatory marker; male; mouse model; neuroinflammation; novel; physical abuse; preclinical study; public health relevance; receptor; receptor expression; tool

 DESCRIPTION (provided by applicant): Substance use disorder (SUD) is a devastating psychopathology that is without FDA-approved drug therapies. One promising target for pharmacological intervention are CB2 cannabinoid receptors (CB2R). Previous studies have demonstrated that CB2R agonists reduce intravenous self-administration (SA) of cocaine and inhibit cocaine-induced hyperlocomotion. Since CB2R agonists have very few overt behavioral effects, they represent a promising new avenue for the treatment of SUD. Unfortunately, a lack of good experimental tools for their study inhibits further progress in uncovering the potential fo manipulation of CB2R signaling to treat SUDs. We have recently developed a transgenic mouse in which CB2R expression is coupled to eGFP expression and the CB2R gene is "floxed", thus can be conditionally deleted (CB2Rtg). This mouse model allows for enhanced detection and enables conditional deletion of the CB2R. Exposure to cocaine is accompanied by microglial activation and reduced microglial activation is associated with reduced cocaine seeking. Microglia express CB2R, which is increased upon microglial activation. Microglial CB2R promote a neuroprotective phenotype, including suppressed release of pro-inflammatory cytokines. Recent studies also demonstrate that CB2R are expressed in DA neurons and function to inhibit DA release. We will test two hypotheses with the experiments in this proposal: that chronic cocaine exposure increases expression of microglial CB2R and that CB2R agonists act via microglial and DA neuronal CB2R to reduce cocaine SA. We will test these hypotheses with two aims. In aim one, we will use the eGFP reporter feature of the CB2Rtg to determine the effects of cocaine on CB2R expression. In aim two, we will use the floxed feature of the CB2Rtg to specifically delete CB2R from microglia and DA neurons; then apply a subtraction approach to explore the cellular site of action of CB2R agonists to reduce locomotor activity and cocaine SA. Successful completion of these studies will impact understanding of the effects of cocaine on neuroinflammation and CB2R expression; and the roles of CB2R in regulating cocaine intake through clarification of the cell types(s) that are involved in the inhibitory actions of CB2R agonists. We will also establish conditional CB2R-/- mouse lines for further studies of the role of this very interesting receptor in brain function. Thus, these studies will impact mechanistic examination of cocaine effects on the brain and provide important new tools for the study of the CB2R in the brain.

 描述（由申请人提供）：物质使用障碍（SUD）是一种毁灭性的精神病理学，没有FDA批准的药物治疗。药理学干预的一个有希望的靶点是CB2大麻素受体（CB2R）。先前的研究已经证明，CB2R激动剂减少可卡因的静脉内自我给药（SA）并抑制可卡因诱导的过度运动。由于CB2R激动剂几乎没有明显的行为效应，因此它们代表了治疗SUD的有希望的新途径。不幸的是，缺乏良好的实验工具，他们的研究抑制了进一步的进展，揭示了潜在的操纵CB2R信号治疗SUD。我们最近开发了一种转基因小鼠，其中CB2R表达与eGFP表达偶联，并且CB2R基因是"floxed"的，因此可以有条件地缺失（CB2Rtg）。该小鼠模型允许增强的检测，并能够有条件地删除CB2R。暴露于可卡因伴随着小胶质细胞活化，并且减少的小胶质细胞活化与减少的可卡因寻求相关。小胶质细胞表达CB2R，其在小胶质细胞活化后增加。小胶质细胞CB2R促进神经保护表型，包括抑制促炎细胞因子的释放。最近的研究还表明，CB2R在DA神经元中表达，并具有抑制DA释放的功能。我们将测试两个假设的实验在这个建议：慢性可卡因暴露增加表达的小胶质细胞CB2R和CB2R激动剂通过小胶质细胞和DA神经元CB2R，以减少可卡因SA。我们将以两个目标来检验这些假设。在目的一中，我们将使用CB2Rtg的eGFP报告基因特征来确定可卡因对CB2R表达的影响。在目标二中，我们将使用CB2Rtg的floxed特征来特异性地从小胶质细胞和DA神经元中删除CB2R;然后应用减法方法来探索CB2R激动剂的细胞作用位点以减少运动活性和可卡因SA。这些研究的成功完成将影响对可卡因对神经炎症和CB2R表达的影响的理解;以及通过澄清参与CB2R激动剂抑制作用的细胞类型，CB2R在调节可卡因摄入中的作用。我们还将建立条件性CB2R-/-小鼠系，为进一步研究CB2R在小鼠体内的作用奠定基础。 大脑功能中一个非常有趣的受体。因此，这些研究将影响可卡因对大脑作用的机制检查，并为研究大脑中的CB2R提供重要的新工具。