Project 5 Modulation and Function of 5HT2C Receptors

5-羟色胺受体2C亚型(5HT2CR)与许多人类精神疾病和 行为障碍，包括MOD、心境恶劣、强迫症、焦虑和精神分裂症。 来自Emeson实验室的研究首次证明5HT2CR的功能是 由一种被称为RNA编辑的新的RNA修饰过程调制。编辑5HT2CR文字记录是 负责多达24种5HT2CR亚型的细胞特异性表达，并被提议 代表一种调节机制，通过改变细胞对细胞外信号的反应 受体G蛋白相互作用的有效性和特异性。最近的研究表明，Altera- 精神障碍患者对抗抑郁药物反应的5HT2cR编辑反应 以及抗精神病药物治疗。拟议研究的长期目标是定义细胞 5HT2CR信号的调控机制，编辑后的5HT2CR等位基因的生理意义。 5HT2cR编辑和情感障碍之间的形式和可能的关系。项目5：调制 和5-HT2C受体的功能，Ron Emeson提出了三个目标来更全面地阐明该区域- 发育中神经系统中5HT2cR编辑的特定模式，以检查遗传和表观遗传学 调制5HT2CR编辑模式并利用转基因小鼠品系，这种品系唯一- Ly表达一个编辑过的5HT2CR亚型，以检测多个5HT2CR的生理相关性 在Aim I中，Emeson将使用焦磷酸测序、引物延伸和基于qRT-PCR的策略。 EGES确定脑内5HT2cR mRNAs的区域特异性表达谱 5HT2CR在成年期的表达，5HT2pR编辑的变化与5HT信号改变的小鼠品系 ING(如SERT多态、Pet-1基因敲除、重组近交系)，以及定义 5HT2CR编辑在已鉴定的基础状态下的下丘脑神经元以及对药物和 生理上的干扰。在AIM II中，Emeson建议进一步开发完全不同于其他基因的突变小鼠品系。 按下5HT2cR的未编辑(INI)或完全编辑(VGV)亚型，因为这些亚型表明 受体G蛋白偶联效率差异最大。这些研究将检验和描述 5HT2CRmRNA和蛋白表达的模式和水平并评估其分子基础 表达INI的小鼠5HT2CR表达减少可能代表适应性内环境平衡 机制。这些研究将扩展到检查突变小鼠信号的变化。 GTPy35S结合和5HT2CR介导的反应性的变化 卵皮质素的表达和随后的取食行为。在AIM III中，Emeson将检查表型 单一5HT2CR亚型单独表达的后果，关注观察到的 表达INI的小鼠的母性关怀，以及中脑边缘多巴胺介导的可能 这是这些行为改变的基础。

The 2C-subtype of serotonin receptor (5HT2CR) has been implicated in a number of human psychiatric and behavioral disorders, including MOD, dysthymia, obsessive-compulsive disease, anxiety, and schizophrenia. Studies from the Emeson laboratory were the first to demonstrate that that the function of the 5HT2CR is modulated by a novel RNA modification process referred to as RNA editing. Editing of 5HT2CR transcripts is responsible for the cell-specific expression of as many as twenty-four 5HT2CR isoforms and is proposed to represent a regulatory mechanism by which cells modulate their response to extracellular signals by altering the efficacy and specificity of receptorG-protein interactions. More recent studies have demonstrated altera- tions in 5HT2cR editing in patients diagnosed with psychiatric disorders and in response to antidepressant and antipsychotic treatment. The long term objectives of the proposed research are to define the cellular mechanisms involved in the regulation of 5HT2CR signaling, the physiologic relevance of edited 5HT2CR iso- forms and possible relationships between 5HT2cR editing and affective disorders. In Project 5: Modulation and Function of 5-HT2c Receptors, Ron Emeson proposes three Aims to more fully elucidate the region- specific pattern of 5HT2cR editing in the developing nervous system, to examine genetic and epigenetic modulation of 5HT2CR editing patterns and to take advantage of genetically-modified mouse strains that sole- ly express a single, edited isoform of the 5HT2CR to examine the physiologic relevance of multiple 5HT2CR species in the CNS.In Aim I, Emeson will use pyrosequencing, primer-extension, and qRT-PCR-based strat- egies to define the region-specific repertoire of 5HT2cR mRNAs expressed in the brain from the onset of 5HT2CR expression through adulthood, changes in 5HT2pR editing in mouse strains with altered 5HT signal- ing (e.g.SERT polymorphisms, Pet-1knockout, recombinant inbred strains), as well as define the pattern of 5HT2CR editing in identified hypothalamic neurons in the basal state and in response to pharmacologic and physiologic perturbations. In Aim II, Emeson proposes to further develop mutant mouse strains solely ex- pressing the non-edited (INI) or fully-edited (VGV) isoforms of the 5HT2cR, since these isoforms demonstrate the greatest differences in receptorG-protein coupling efficacy. These studies will examine and characterize ":he pattern and level of expression of 5HT2CR mRNA and protein expression and assess the molecular basis of a decrease in 5HT2CR expression in INI-expressing mice that may represent an adaptive homeostatic mechanism. These studies will be extended to examine alterations in signaling for mutant mice using GTPy35S binding and changes in 5HT2CR-mediated responsiveness by assessing alterations in both pro-opi- omelanocortin expression and subsequent feeding behavior. In Aim III, Emeson will examine the phenotypic consequences resulting from sole expression of a single 5HT2CR isoform, focusing upon observed deficits in maternal care in INI-expressing mice, as well as mesolimbic dopamine-mediated reward behaviors that may underlie such behavioral alterations.