Dusonchet Julien, Bensadoun Jean-Charles, Schneider Bernard L, Aebischer Patrick
Ecole Polytechnique Fédérale de Lausanne, Brain Mind Institute, EPFL SV BMI LEN, AI 1207, Lausanne, Switzerland.
Neurobiol Dis. 2009 Jul;35(1):32-41. doi: 10.1016/j.nbd.2009.03.013. Epub 2009 Apr 5.
Loss of function of parkin, an ubiquitin ligase, is responsible for autosomal recessive juvenile parkinsonism (AR-JP). Parkin-associated endothelin receptor-like receptor (Pael-R) was identified as an authentic substrate of parkin and is thought to accumulate abnormally following loss of parkin activity, causing neurodegeneration of nigral dopaminergic neurons in AR-JP patients. Our aim is therefore to generate a model of AR-JP through overexpression of Pael-R in the nigrostriatal system of adult rats. Using recombinant adeno-associated virus pseudotyped with the serotype 6 capsid (rAAV2/6) as a gene delivery tool, we achieved targeted and robust overexpression of rat Pael-R in nigral neurons and their striatal terminals. Overexpressed Pael-R was shown to accumulate very rapidly in an insoluble form. Accumulation of the receptor triggered a rapid and severe loss of nigral neurons and nigrostriatal fibers and terminals. No cell recovery was observed for up to 6 months post-injection. GABAergic neurons of the globus pallidus were unaffected by Pael-R overexpression, highlighting the selective vulnerability of nigral dopaminergic neurons to abnormal levels of Pael-R. Pael-R-induced degeneration also led to a depletion of striatal dopamine resulting in spontaneous motor impairments, as measured in the cylinder and stepping tests for forelimb akinesia. Interestingly, behavioral deficits of individual animals were correlated with the extent of the nigrostriatal lesion. Insoluble accumulation of Pael-R in the nigrostriatal system of adult rats represents, therefore, a chronic, rapidly progressing and specific model of AR-JP, which recapitulates major pathological hallmarks of the disease.
泛素连接酶帕金蛋白功能缺失会导致常染色体隐性遗传性少年帕金森病（AR-JP）。帕金蛋白相关内皮素受体样受体（Pael-R）被确定为帕金蛋白的一个真正底物，并且人们认为在帕金蛋白活性丧失后它会异常积聚，从而导致AR-JP患者黑质多巴胺能神经元发生神经退行性变。因此，我们的目标是通过在成年大鼠黑质纹状体系统中过表达Pael-R来建立AR-JP模型。我们使用血清型6衣壳假型化的重组腺相关病毒（rAAV2/6）作为基因传递工具，在黑质神经元及其纹状体终末实现了大鼠Pael-R的靶向且高效过表达。结果显示，过表达的Pael-R会以不溶性形式迅速积聚。该受体的积聚引发了黑质神经元以及黑质纹状体纤维和终末的快速且严重丧失。注射后长达6个月未观察到细胞恢复。苍白球的GABA能神经元未受Pael-R过表达的影响，这突出了黑质多巴胺能神经元对Pael-R异常水平的选择性易损性。Pael-R诱导的变性还导致纹状体多巴胺耗竭，从而导致自发运动障碍，这在前肢运动不能的圆筒试验和阶梯试验中得到了测量。有趣的是，个体动物的行为缺陷与黑质纹状体损伤程度相关。因此，成年大鼠黑质纹状体系统中Pael-R的不溶性积聚代表了一种慢性、快速进展且特异的AR-JP模型，该模型概括了该疾病的主要病理特征。
