Signaling regulation in the striatum in Parkinson's disease

描述（由申请人提供）：G蛋白偶联受体激酶（GRK）和抑制因子协同作用，确保G蛋白偶联受体介导的G蛋白介导的信号传导的快速终止。通过纹状体多巴胺受体的多巴胺能信号传导在控制正常和病变大脑的多种形式的行为中起关键作用。多巴胺受体信号异常与帕金森病（PD）和多巴胺替代疗法引起的运动并发症（如左旋多巴诱导的运动障碍）密切相关。多巴胺受体经历GRK依赖性和抑制蛋白依赖性脱敏，这一过程中的缺陷可能是PD患者多巴胺缺失或多巴胺能药物引起的信号异常的基础。慢病毒介导的GRK6在多巴胺缺失纹状体中的过表达使啮齿动物和灵长类动物PD模型中的行为和多巴胺受体信号正常化，表明grk在大脑多巴胺受体的调节中起关键作用。本项目旨在探索GRK和arrest在活体动物多巴胺能行为调节中的作用，以及GRK在体内功能的精细分子机制。第一目的将研究GRK亚型在对抗左旋多巴诱导的旋转和对左旋多巴的行为致敏中的特定作用。我们将注射编码野生型GRK异构体、具有不同功能的突变型GRK或GRK microrna的慢病毒，将选择的异构体敲低到多巴胺枯竭纹状体中，并测试重复左旋多巴给药后的旋转行为。Aim 2旨在测试同时过表达一种停搏蛋白和一种GRK是否比单独过表达同一种GRK在抑制左旋多巴诱导的运动症状方面更有效。在Aim 3中，我们将研究GRK表达或功能紊乱引起的下游信号通路的改变。在Aim 4中，将研究利用受体脱敏过程改善帕金森病治疗的可行性。这些实验结果将有助于梳理GRK和阻滞素同工型在体内调节大脑多巴胺能信号传导中的具体作用。这些研究将为开发新的治疗方法铺平道路，以控制帕金森病的运动缺陷和左旋多巴治疗的并发症。公共卫生相关性：帕金森病是一种引起运动问题的神经退行性疾病，用左旋多巴治疗，左旋多巴是一种有效的药物，但随着时间的推移会失去效果，并有严重的副作用。我们不知道左旋多巴治疗产生问题的原因，也不知道它是如何产生副作用的。该项目旨在探索被称为阻滞蛋白和G蛋白偶联受体激酶的蛋白质是否在左旋多巴治疗的并发症中发挥作用。

DESCRIPTION (provided by applicant): G protein-coupled receptor kinases (GRK) and arrestins act in concert to ensure rapid termination of G protein-mediated signaling by G protein-coupled receptors. Dopaminergic signaling via striatal dopamine receptors play a critical role in controlling multiple forms of behavior in the normal and diseased brain. Abnormalities of signaling by dopamine receptors have been strongly implicated in Parkinson's disease (PD) and motor complications caused by dopamine replacement therapy such as L-DOPA-induced dyskinesia. Dopamine receptors undergo GRK- and arrestin-dependent desensitization, and deficits in this process may underlie signaling abnormalities caused by the loss of dopamine or by dopaminergic drugs in PD. The lentivirus-mediated overexpression of GRK6 in the dopamine-depleted striatum normalizes behavior and dopamine receptor signaling in the rodent and primate animal models of PD, suggesting a critical role for GRKs in the regulation of dopamine receptors in the brain. This project is designed to explore the role of GRKs and arrestins in the dopaminergic regulation of behavior in live animals as well as fine molecular mechanisms of the GRK function in vivo. First Aim will examine specific roles of GRK isoforms in antagonizing L-DOPA- induced rotations and behavioral sensitization to L-DOPA in hemiparkinsonian rats. We will inject lentiviruses encoding wild type GRK isoforms, mutant GRKs with different functions selectively disabled, or GRK microRNAs to knockdown select isoforms into the dopamine-depleted striatum and test for rotational behavior following repeated L-DOPA administration. The Aim 2 is designed to test whether simultaneous overexpression of an arrestin and a GRK is more potent than overexpression of the same GRK alone in suppressing L-DOPA-induced motor symptoms. In Aim 3, we will examine the alterations in down-stream signaling pathways caused by perturbations in the GRK expression or function. In Aim 4, the feasibility of harnessing the receptor desensitization process to improve therapy in Parkinson's disease will be examined. The results of these experiments will help to sort out specific roles of GRK and arrestin isoforms in regulating dopaminergic signaling in the brain in vivo. The studies will pave the way to development of novel therapeutic approaches to control motor deficits in Parkinsons' disease and complications of L-DOPA therapy. PUBLIC HEALTH RELEVANCE: Parkinson's disease is a neurodegenerative disorder that causes movement problems treated with levodopa, which is an effective drug but looses effectiveness in time and has severe side effects. We do not know what causes problems with levodopa therapy or how its produces its side effects. This project is designed to explore whether the proteins called arrestins and G protein-coupled receptor kinases play a role in complications of the levodopa therapy.