a-Synuclein in Transgenic Models of MSA

多系统萎缩症是一种进行性、退行性神经系统疾病，以帕金森综合征、共济失调和自主神经功能障碍为特征。MSA的主要病理特征是少突胶质细胞中存在由α-突触核蛋白（SYN）组成的胶质细胞胞浆内含物。最近的研究表明，SYN在神经元和胶质细胞中的异常积累导致细胞功能障碍和神经变性。在之前的资助期间，我们开发了MSA的体外和体内模型，表明线粒体损伤和过度磷酸化的SYN聚集体的产生可能有助于MSA的发病机制。然而，这些途径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，由于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）活化和毒性SYN磷酸化。主要目的是调查 在MSA样SYN转基因（tg）模型中观察神经变性，以确定减少SYN积累是否代表MSA的治疗策略。目标1。为了确定过度磷酸化的SYN在少突胶质细胞中积累在神经毒性机制中的作用，我们将分析表达野生型（wt）人SYN或不可磷酸化的SYN突变体（S129 A）的髓鞘碱性蛋白（MBP）-SYN tg小鼠中的SYN积累和神经变性。将MBP-SYNwt tg小鼠与GRK 2或GRKS缺陷小鼠杂交，MBP-SYNwt tg小鼠和MBP-SYN（S129 A）tg小鼠将接受在少突胶质细胞特异性启动子（MBP）下表达GRK 2或GRK 5的慢病毒的脑内感染。目标2.为了确定线粒体功能障碍和氧化应激对GRK活化和SYN磷酸化的作用，将用3-硝基丙酸攻击MBP-SYN（wt和S129 A）小鼠和少突胶质细胞。目标3.为了确定MSA模型中的神经元损伤是否可以通过减少SYN聚集或抑制GRK来改善，将用利福平或GRK阻断剂处理MBP-SYN wt tg小鼠。将评估行为表现、神经变性、SYN寡聚化和磷酸化以及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 oligodendrocj^es 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