a-Synuclein in Transgenic Models of MSA

多系统萎缩(MSA)是一种进行性退行性神经系统疾病，以帕金森病、共济失调和自主神经功能障碍为特征。MSA的主要病理特征是在少突胶质细胞中存在由α-突触核蛋白(SYN)组成的胶质细胞质内含物。最近的研究表明，SYN在神经元和神经胶质细胞中的异常积聚会导致细胞功能障碍和神经变性。在之前的资助期间，我们建立了MSA的体外和体内模型，表明线粒体损伤和过度磷酸化的SYN聚集体的产生可能参与了MSA的发病。然而，这些通路促进少突胶质细胞功能障碍和神经变性的机制尚不清楚。 在这次更新中，我们将研究线粒体功能障碍在SYN磷酸化和毒性中的作用。我们的中心假设是，线粒体功能障碍引起的氧化应激可能促进G蛋白偶联受体激酶(GRK)的激活和毒性SYN的磷酸化。主要目的是调查 在类似MSA的SYN转基因(TG)模型中进行神经退行性变，以确定减少SYN积聚是否代表MSA的治疗策略。目的1.为了探讨SYN过度磷酸化在神经毒性机制中的作用，我们分析了髓鞘碱性蛋白(MBP)-表达野生型(Wt)人SYN或非磷酸化SYN突变体(S129A)的SYN TG小鼠的SYN蓄积和神经变性。MBP-SYNwt TG小鼠将与GRK2或GRKS缺陷小鼠杂交，MBP-SYNwt TG小鼠和MBP-SYN(S129A)TG小鼠将在少突胶质细胞特异性启动子(MBP)下接受表达GRK2或GRK5的慢病毒脑内感染。目的2.用3-硝基丙酸刺激MBP-SYN(wt和S129A)小鼠和少突胶质细胞，探讨线粒体功能障碍和氧化应激在GRK激活和SYN磷酸化中的作用。目的：为了确定是否可以通过减少SYN聚集或抑制GRKs来改善MSA模型中的神经元损伤，我们将用利福平或GRK阻滞剂来治疗MBP-SYN wt TG小鼠。将评估行为表现、神经退行性变、SYN寡聚和磷酸化以及GRK活性。

Multiple system atrophy (MSA) is a progressive, degenerative neurological disorder characterized by parkinsonism, ataxia & dysautonomia. The cardinal pathological feature of MSA is the presence of glial cytoplasmic inclusions composed of alpha-synuclein (SYN) in oligodendrocytes. Recent studies suggest that abnormal SYN accumulation in neurons & glia leads to cellular dysfunction & neurodegeneration. During the previous funding period we developed in vitro & in vivo models of MSA showing that mitochondrial damage & hyperphosphorylated SYN aggregate generation may contribute to the pathogensis of MSA. However, mechanisms by which these pathways promote oligodendrogial dysfunction & neurodegeneration are unclear. In this renewal we will investigate the role of mitochondrial dysfunction in SYN phosphorylation & toxicity. Our central hypothesis is that oxidative stress due to mitochondrial dysfuntion may promote G-protein coupled receptor kinase (GRK) activation & toxic SYN phosphorylation. The main objective is to investigate neurodegeneration in MSA-like SYN transgenic (tg) models to determine if reducing SYN accumulation represents a therapeutic strategy for MSA. Aim 1. In order to determine the role of hyperphosphorylated SYN accumulation in oligodendrocytes in the mechanisms of neurotoxicity, we will analyze SYN accumulation & neurodegeneration in myelin basic protein (MBP)-SYN tg mice expressing wild-type (wt) human SYN or a nonphosphorylatable SYN mutant (S129A). MBP-SYNwt tg mice will be crossed with GRK2- or GRKS-deficient mice & MBP-SYNwt tg mice & MBP-SYN(S129A) tg mice will receive intra-cerebral infections with lentivirus expressing GRK2 or GRK5 under a oligodendroglial specific promoter (MBP). Aim 2. In order to determine the role of mitochondrial dysfunction & oxidative stress on GRK activation & SYN phosphorylation, MBP-SYN (wt and S129A) mice & oligodendroglial cells will be challenged with 3- nitropropionic acid. Aim 3. In order to determine if neuronal impairments in MSA models can be ameliorated by reducing SYN aggregation or inhibiting GRKs, MBP-SYN wt tg mice will be treated with rifampicin or GRK blockers. Behavioral performance, neurodegeneration, SYN oligomerization & phosphorylation & GRK activity will be assessed.