Cell-specific Modulation of Feeding Behavior by Serotonin 2C Receptor RNA Processing

5-羟色胺 2C 受体 RNA 加工对摄食行为的细胞特异性调节

基本信息

批准号：
10438652
负责人：
Ronald B. Emeson
金额：
$ 38.76万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-22 至 2023-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10438652
关键词：
Ablation Adenosine Adult Alternative Splicing Amino Acids Animal Model Animals Anti-Obesity Agents Appetite Depressants Behavior Behavior Disorders Biological Models Body Composition Brain Brain region Cations Cell Separation Cell physiology Cells Characteristics Chromosome 15 Complement Coupling Data Desire for food Development Diagnosis Diet Disease Eating Endoplasmic Reticulum Engineering Etiology Event Exhibits Exons Failure to Thrive Feeding behaviors G-Protein-Coupled Receptors GTP-Binding Proteins Gene Cluster Gene Expression Profiling Genetic Transcription Glucose Health Heterodimerization Homeostasis Human Hyperphagia Hypothalamic structure Inosine Insulin Knockout Mice Length Mediating Melanocortin 4 Receptor Melanocyte stimulating hormone Mental disorders Metabolic Metabolism Methods Molecular Motor Activity Mus Muscle hypotonia Mutant Strains Mice Neurons Non-Insulin-Dependent Diabetes Mellitus Obesity Oligonucleotides Pathogenesis Pathology Pathway interactions Patients Pattern Pharmacology Phenotype Physiological Population Prader-Willi Syndrome Pro-Opiomelanocortin Production Protein Isoforms RNA RNA Editing RNA I RNA Processing RNA Splicing Receptor Signaling Regulation Research Role Satiation Serotonin Receptor 5-HT2C Serum Signal Transduction Small Nucleolar RNA Structure of nucleus infundibularis hypothalami Surface Testing Therapeutic Transcript Transmembrane Domain Weaning cell type combinatorial comorbidity diet and exercise experimental study extracellular feeding food consumption in vivo insight maternal imprint member metabolic rate mouse model mutant mutant mouse model novel paraventricular nucleus receptor receptor expression receptor function reduced food intake response serotonin receptor

项目摘要

The 2C-subtype of serotonin receptor (5HT2C) has been implicated in numerous human psychiatric and behavioral disorders. The best-characterized function for this receptor however, involves an anorectic response mediated by 5HT2C receptor expression in pro-opiomelanocortin (POMC)-producing neurons in the arcuate nucleus of the hypothalamus to modulate feeding behavior and energy homeostasis. Transcripts encoding the 5HT2C receptor can be modified differentially by RNA processing events that include alternative splicing and adenosine- to-inosine (A-to-I) editing. 5HT2C transcripts can undergo up to five A-to-I editing events to generate as many as 24 protein isoforms that differ in G-protein coupling efficacy and constitutive activity, while alternative splicing can produce a truncated version of the receptor (5HT2C-tr) which decreases receptor signaling by heterodimerization and sequestration of the full-length receptor within the endoplasmic reticulum. Thus, the processing of 5HT2C RNAs may represent a critical regulatory mechanism by which neurons can modulate their responsiveness to changing extracellular signals by altering the identity of functionally distinct 5HT2C isoforms expressed in specific neuronal cell types. Unfortunately, heterogeneous expression in many brain regions and within different neuronal populations has hampered efforts to understand how 5HT2C RNA processing contributes to the modulation of specific circuits or behaviors. The long-term objectives of the proposed research are to define the cellular mechanisms that regulate 5HT2C expression and signaling, as well as possible relationships between 5HT2C processing and feeding-related pathologies. Recent studies have identified alterations in both 5HT2C receptor expression and 5HT2C-mediated behaviors in mouse models and patients diagnosed with Prader-Willi Syndrome (PWS). Furthermore, mutant mice engineered solely to express the fully edited 5HT2C receptor isoform exhibit phenotypic characteristics of PWS including a failure to thrive and post-weaning hyperphagia. Thus, RNA editing and splicing have dramatic consequences on feeding behavior suggesting that improper processing of 5HT2C transcripts may represent a contributing factor to disorders of feeding and metabolism. In the current application, mutant mouse lines in which expression of the 5HT2C-tr can be induced in POMC neurons will be characterized to assess the functional importance of 5HT2C-tr modulation for 5HT2C signaling in vivo. To assess whether manipulation of 5HT2C RNA processing represents a physiological mechanism by which neuron-dependent feeding signals are modulated, three distinct model systems will be used to examine the effects of diet, exercise and pharmacologic manipulation on 5HT2C RNA processing in POMC neurons. Finally, we will test the ability of specific, edited isoforms of the 5HT2C receptor to rescue the hyperphagia, maturity-onset obesity and type II diabetes associated with the 5HT2C-null phenotype when inducibly expressed solely in POMC neurons. It is anticipated that the proposed studies will provide critical insights into molecular etiology of human disorders associated with alterations in feeding and energy homeostasis.

血清素受体 (5HT2C) 的 2C 亚型与许多人类精神和行为障碍有关。然而，该受体最典型的功能涉及由弓状核中产生阿片黑皮素原 (POMC) 的神经元中 5HT2C 受体表达介导的厌食反应下丘脑调节进食行为和能量稳态。编码 5HT2C 的转录本受体可以通过RNA加工事件进行差异性修饰，包括选择性剪接和腺苷- 肌苷（A-to-I）编辑。 5HT2C 转录本可以经历最多 5 次 A 到 I 编辑事件，以生成多达 24 种蛋白质亚型在 G 蛋白偶联功效和组成活性方面有所不同，而选择性剪接可以产生截短形式的受体 (5HT2C-tr)，通过异二聚化和在内质网内隔离全长受体来减少受体信号传导。因此，处理 5HT2C RNA 可能代表了一种关键的调节机制，通过该机制，神经元可以通过改变在功能上不同的 5HT2C 亚型的身份来调节其对变化的细胞外信号的反应。特定的神经元细胞类型。不幸的是，许多大脑区域和内部的异质表达不同的神经元群体阻碍了理解 5HT2C RNA 处理如何促进特定回路或行为的调节的努力。拟议研究的长期目标旨在定义调节 5HT2C 表达和信号传导的细胞机制，以及 5HT2C 加工和喂养相关病理之间可能的关系。最近的研究发现了变化小鼠模型和诊断患有 5HT2C 的患者中 5HT2C 受体表达和 5HT2C 介导的行为普瑞德威利综合症（PWS）。此外，突变小鼠经过专门改造以表达完全编辑的 5HT2C 受体同种型表现出 PWS 的表型特征，包括发育迟缓和断奶后食欲亢进。因此，RNA 编辑和剪接对摄食行为产生巨大影响，表明 5HT2C 转录物的不当处理可能是导致摄食和代谢紊乱的一个因素。在当前的应用中，可以在 POMC 中诱导表达 5HT2C-tr 的突变小鼠系将表征神经元以评估 5HT2C-tr 调节对体内 5HT2C 信号传导的功能重要性。评估 5HT2C RNA 加工的操纵是否代表了一种生理机制，通过该机制调节神经元依赖性喂养信号，将使用三个不同的模型系统来检查饮食、运动和药物操作对 POMC 神经元 5HT2C RNA 加工的影响。最后，我们将测试 5HT2C 受体的特定、编辑亚型拯救食欲过盛、成熟开始的能力当仅在 POMC 中诱导表达时，肥胖和 II 型糖尿病与 5HT2C 缺失表型相关神经元。预计所提出的研究将为人类的分子病因学提供重要的见解。与进食和能量稳态改变相关的疾病。