Control of serotonergic signaling by chimeric light aactivated receptors

描述(申请人提供)：哺乳动物大脑中的5-羟色胺能递质系统在情绪、性行为、睡眠/醒来周期、血压控制和呼吸等各种生理功能中发挥着重要作用。5-羟色胺通过5-羟色胺受体介导其作用，5-羟色胺受体是一种G蛋白偶联受体，表达在5-羟色胺神经元及其大脑内的靶标上。5-羟色胺受体，5-羟色胺-1 A，耦合到Gi/o信号通路，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，了解这一受体通路如何在脑内和活体动物中调节5-羟色胺能张力、功能和5-羟色胺相关行为是非常重要的。在这里，我描述了一种开发光激活GPCRs的方法，该GPCRs激活5HT-1a特异性受体途径。我将通过突变脊椎动物视紫红质的细胞内结构域来产生嵌合受体，方法是将它们交换为5HT-1A受体的结构域。然后，我将描述这种嵌合受体的功能，并评估它在异源表达系统中激活5HT特异性信号的能力。最后，我将评估其挽救5HT-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描述神经元功能上的受体途径，并将是相对于药物操作的重大进步，药物操作受到药代动力学的限制，在活的、完整的动物身上使用可能会很麻烦。这种光激活的工具可以用来精确地操纵特定神经元群体中的5-羟色胺能信号级联，这将导致对正常生理的更清晰的理解，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，特异性的5-羟色胺受体与功能和疾病的关系尚不清楚。为了解决这个问题，我建议开发和测试光激活分子，它将激活神经元中特定的5-羟色胺途径。

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.