Neural substrates of elevated striatal dopamine synthesis and release in schizophrenia

精神分裂症纹状体多巴胺合成和释放升高的神经基质

• 批准号: 10409842
• 负责人: JILL RENEE' Glausier
• 金额: $ 19.85万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10409842
• 关键词: Affect; Anatomy; Antipsychotic Agents; Autopsy; Axon; Back; Biological Models; Brain; Characteristics; Choline O-Acetyltransferase; Chronic; Clinical; Confocal Microscopy; Corpus striatum structure; Data; Development; Disease; Dopamine; Dopamine D2 Receptor; Dorsal; Drug Exposure; Electron Microscopy; Electrons; Enzymes; Exhibits; Exposure to; Foundations; Functional disorder; Future; Human; Immunofluorescence Microscopy; Individual; Interneurons; Label; Measures; Midbrain structure; Molecular; Monkeys; Nicotinic Receptors; Onset of illness; Proteins; Psychiatry; Psychoses; Psychotic Disorders; Resolution; Role; Schizophrenia; Signal Transduction; Site; Specificity; Synapses; Testing; Therapeutic Effect; Transferase; Transmission Electron Microscopy; Tyrosine 3-Monooxygenase; Vesicle; atypical antipsychotic; brain tissue; cholinergic; cohort; density; design; dopamine transporter; dopaminergic neuron; evidence base; in vivo; neural circuit; neuroimaging; novel; postsynaptic; presynaptic; relating to nervous system; reuptake; transmission process; vesicular monoamine transporter 2; vesicular release

7. PROJECT SUMMARY/ABSTRACT Psychosis is a core clinical feature of schizophrenia (SZ) associated with elevated dopamine (DA) synthesis and release in the associative striatum (AST), but not the limbic striatum (LST). Determining the molecular and subcellular substrates of this region-specific presynaptic pathophysiology of psychosis in the disease state requires studies at the site of DA release, DA axonal boutons. This level of resolution in humans can only be achieved in postmortem brain studies. Elevated presynaptic DA signaling in the AST in SZ could be due to molecular changes within DA boutons. Specifically, greater protein levels of tyrosine hydroxylase (TH), vesicular monoamine transporter 2 (VMAT2) or the DA transporter (DAT), which govern DA synthesis, packaging for vesicular release and reuptake into the bouton, respectively, could represent molecular substrates of this pathophysiology. These molecular changes would be accompanied by ultrastructural alterations reflecting greater DA vesicular release. Alternately, or additionally, a greater density of DA boutons could be the substrate for elevated presynaptic DA signaling. Thus, in Aim 1 we test each of these possibilities by using triple-label immunofluorescence and confocal microscopy in SZ and unaffected comparison (CON) subjects to simultaneously quantify the abundance of TH, VMAT2 and DAT within DA boutons and the density of DA boutons in the AST and LST (Exp 1.1), and DA vesicle density is quantified via serial section transmission electron microscopy (Exp 1.2). Studies are repeated in monkeys chronically exposed to antipsychotic drugs (Exp 1.3). The findings in Aim 1 may result from alterations to local striatal cholinergic interneurons (ChIs) that affect DA boutons. Indeed, because markers of presynaptic DA signaling are normally greater in the AST than LST, an exaggeration of the factors that contribute to this regional specificity might underlie the AST-specific finding in SZ. ChIs are a compelling candidate as they exhibit greater functional and anatomical measures in the AST than LST and potently regulate DA synthesis and release by providing direct axo-axonic inputs to DA boutons. Activation of nicotinic acetylcholine receptors containing the β2 subunit (nAChRβ2) located on DA boutons induces DA release independent of DA neuron firing in the midbrain. Measures reflecting elevated presynaptic DA signaling in the AST in SZ might be the consequence of a greater proportion of DA boutons receiving ChI inputs and/or higher levels of molecular determinants of ChI synaptic strength, such as levels of ACh transferase (ChAT) and/or nAChRβ2. Thus, in Aim 2 we utilize quadruple-label immunofluorescence and confocal microscopy to simultaneously quantify the proportion of DA boutons receiving a ChI axo-axonic input and the abundance of ChAT and nAChRβ2 at these inputs in the AST and LST. As in Aim 1, studies are repeated in monkeys chronically exposed to antipsychotic drugs. These subcellular, molecular and ultrastructural analyses will provide the first comprehensive, region-specific analysis of the neural substrates and upstream factors of elevated presynaptic DA signaling in the AST of SZ and form the foundation of a future R01 application.

7。项目摘要/摘要 精神病是与多巴胺升高（DA）合成相关的精神分裂症（SZ）的核心临床特征 在关联纹状体（AST）中释放，但没有边缘纹状体（LST）。确定分子和 该疾病状态下精神病的该区域特异性前病理生理学的亚细胞底物 需要在DA释放的DA Axonal Boutons的地点进行研究。人类的这种分辨率只能是 在死后脑研究中实现。 SZ中AST中的突触前DA信号升高可能是由于 DA胸子内的分子变化。具体而言，较高的蛋白质水平的酪氨酸羟化酶（Th），水泡 单胺转运蛋白2（VMAT2）或DA转运蛋白（DAT），该转运蛋白（DAT）控制DA合成，包装的包装 囊泡释放和重新摄取分别可以代表这一点的分子底物 病理生理学。这些分子变化将通过反映的超微结构改变来实现 更大的DA囊泡释放。或者，另外，更大密度的da胸部可能是基板 用于升高的突触前DA信号传导。在AIM 1中，我们使用三标签来测试这些可能性 SZ中的免疫荧光和共聚焦显微镜以及未受影响的比较（CON）受试者 类似地量化了da胸子内Th，VMAT2和DAT的抽象以及DA胸子的密度 在AST和LST（EXP 1.1）和DA蔬菜密度通过串行部分透射电子 显微镜（EXP 1.2）。长期暴露于抗精神病药的猴子中重复研究（EXP 1.3）。 AIM 1中的发现可能是由于影响DA的局部纹状体胆碱能中间神经元（CHI）而导致的 胸衣。实际上，由于突触前DA信号的标记通常在AST中大于LST 夸大导致这种区域特异性的因素可能是AST特定发现的基础 SZ。 CHI是一个引人注目的候选人，因为他们在AST中暴露了更大的功能和解剖措施 LST并可能通过向DA胸子提供直接的Axo轴突输入来调节DA综合并释放。 含有β2亚基（NACHRβ2）的烟碱乙酰胆碱受体的激活 诱导DA释放独立于中脑的DA神经元射击。反映突触前升高的措施 SZ中AST中的DA信号传导可能是接收CHI的DA胸部的比例更大的结果 CHI合成强度的输入和/或更高水平的分子确定剂，例如ACH转移酶的水平 （CHAT）和/或NACHRβ2。在AIM 2中，我们利用了四标签标签的免疫荧光和共焦 显微镜，可以轻松量化接收卡轴轴承输入的DA胎子的比例和 在AST和LST中这些输入中聊天和NACHRβ2的抽象。与AIM 1一样，在 长期暴露于抗精神病药的猴子。这些亚细胞，分子和超微结构分析 将提供对神经底物的首次全面，特定于区域的分析和上游因素 SZ AST中的突触前DA信号升高，并构成了未来R01应用的基础。