Control of serotonergic signaling by chimeric light aactivated receptors

描述（由申请人提供）：哺乳动物大脑中的多巴胺能递质系统在各种生理功能中起重要作用，如情绪、性行为、睡眠/觉醒周期、血压控制和呼吸。5-羟色胺通过5 HT受体介导其作用，5 HT受体是在脑内的5 HT神经元及其靶标内表达的G蛋白偶联受体。5 HT受体5 HT-1A与Gi/o信号通路偶联，已被描述为在焦虑和抑郁行为中起主要作用。它也是治疗许多神经精神疾病的重要药物靶点.因此，了解该受体通路如何在脑内和活体动物中调节肾上腺素能紧张度、功能和5-HT相关行为是非常重要的。在这里，我描述了一种方法来开发光激活GPCR，激活5 HT-1A特异性受体途径。我将通过将脊椎动物视紫红质的胞内结构域突变为5 HT-1A受体的胞内结构域来产生嵌合受体。然后，我将表征这种嵌合受体的功能，并评估其在异源表达系统中激活5 HT特异性信号传导的能力。最后，我将评估其拯救5 HT-1A受体敲除小鼠生理表型的能力。这种嵌合受体将能够精确表征神经元功能的受体途径，并且将是对药理学操作的重大进步，药理学操作受到其药代动力学的限制，并且在活的完整动物中使用可能很麻烦。这种光激活工具可用于精确操纵神经元群体中的多巴胺能信号级联，这将导致对正常生理学的更清晰理解，并可能导致新的治疗方法。 5-羟色胺在许多生理功能和许多精神疾病中起着关键作用，然而特异性5-羟色胺受体与功能和疾病的关系在很大程度上是未知的。为了解决这个问题，我建议开发和测试光激活分子，将激活神经元中的特定血清素途径。

DESCRIPTION (provided by applicant): The serotonergic transmitter system in the mammalian brain plays important roles in various physiological functions such as mood, sexual behavior, sleep/wake cycle, blood pressure control and breathing. Serotonin mediates its effect via 5HT receptors, which are G protein coupled receptors that are expressed within 5HT neurons and their targets within the brain. The 5HT receptor, 5HT-1 A, which couple to the Gi/o signaling pathway, has been described to play major roles for anxiety and depressive behaviors. It is also and important drug target for treating many neuropsychiatric disorders. It is therefore of great importance to understand how this receptor pathway acts to modulate serotonergic tone, function, and 5HT related behaviors within the brain and in the living animals. Here, I describe a method to develop light activated GPCRs that activates the 5HT-1A specific receptor pathway. I will generate a chimeric receptor by mutating the intracellular domains of vertebrate rhodopsin by exchanging them for those of the 5HT-1A receptor. I will then characterize the function of this chimeric receptor and assess its ability to activate 5HT specific signaling in a heterologous expression system. Finally, I will assess its ability to rescue physiological phenotypes in 5HT-1A receptor knock-out mice. This chimeric receptor will enable the precise characterization of receptor pathways on neuronal function and would be a significant advance over pharmacologic manipulations, which are limited by their pharmacokinetics and can be cumbersome to use in live, intact animals. This light activated tool could be used to precisely manipulate serotonergic signaling cascades in a defined population of neurons, which will lead to a clearer understanding of normal physiology and may lead to novel therapeutics. Serotonin plays a critical role in many physiological functions and many psychiatric disorders, however the involvement of specific serotonin receptors with function and disease is largely unknown. To address this problem, I propose to develop and test light activated molecules that will activate a specific serotonin pathway in neurons.