New Drosophila Model of VPS35 Parkinsonism

描述(由申请人提供)：帕金森氏病(PD)的更好治疗有越来越多的未得到满足的需求。我们的目标是提高对参与这一神经退行性过程发病机制的分子通路的了解，最终为疾病修改治疗干预找到新的药理靶点。空泡蛋白分选35(VPS35)基因是最新的常染色体显性遗传性帕金森病的致病基因，它强调了逆转录和逆转录依赖运输在帕金森病中的作用。然而，VPS35在帕金森病发病机制中的具体作用尚不清楚，目前还没有VPS35帕金森综合征的动物模型。因此，这项资助申请的目标是开发第一个VPS35帕金森症动物模型。具体地说，我们计划产生一个新的转基因果蝇株，它将允许表达果蝇VPS35的D647N突变(相当于在PD患者中发现的致病D620N突变)。我们预计，在多巴胺能神经元中表达VPS35(D647N)将导致神经元死亡、运动障碍、对鱼藤酮的敏感性增加以及自噬功能受损--这一细胞过程最近参与了包括帕金森病在内的几种神经退行性疾病的发病机制。具体来说，我们假设VPS35是有效的自噬所必需的，并且表达VPS35(D647N)会削弱自噬反应。此外，我们假设VPS35(D647N)突变果蝇将呈现眼睛表型，类似于许多其他神经退行性疾病模型，包括我们的LRRK2转基因果蝇。对眼睛表型的表征将使这种动物模型在未来的基因筛查或药物筛查中具有价值。这一建议将为研究帕金森病的体内发病机制提供新的有价值的工具，有助于阐明这一新发现的逆转录依赖途径在帕金森病发病中的作用机制。这可能会显著推进帕金森病和其他神经退行性疾病的领域，并可能为更好的治疗发现新的药理靶点。

DESCRIPTION (provided by applicant): There is a growing unmet need for a better treatment of Parkinson's disease (PD). Our goal is to improve the understanding of molecular pathways involved in the pathogenesis of this neurodegenerative process, to ultimately find new pharmacological targets for a disease-modifying therapeutic intervention. Identification of Vacuolar protein sorting 35 (VPS35) as the latest autosomal dominant causative gene of PD highlighted the role of retromer and retromer-dependent trafficking in PD. However how exactly VPS35 contributes to PD pathogenesis is entirely unknown, and at present there is no animal model of VPS35 parkinsonism. Therefore the goal of this grant application is to develop the first animal model of VPS35 parkinsonism. Specifically, we are planning to generate a new transgenic Drosophila line that will allow expressing the D647N mutant of Drosophila Vps35 (equivalent to the pathogenic D620N mutation identified in PD patients). We anticipate that expressing Vps35(D647N) in dopaminergic neurons will lead to neuronal death, locomotor deficits, increased sensitivity to rotenone, and impaired autophagy - a cellular process recently implicated in the pathogenesis of several neurodegenerative disorders, including PD. Specifically, we postulate that Vps35 is required for efficient autophagy, and that expressing Vps35(D647N) will impair the autophagic response. In addition, we hypothesize that Vps35(D647N) mutant flies will present with an eye phenotype, similar to many other models of neurodegenerative disorders, including our LRRK2 transgenic fly. Characterization of an eye phenotype would make this animal model valuable in future genetic screens or drug screens. This proposal will provide a new valuable tool to study PD pathogenesis in vivo, one that will help elucidate the mechanisms by which this newly discovered retromer-dependent pathway contributes to PD pathology. This may significantly advance the field of PD and other neurodegenerative disorders, and may uncover new pharmacological targets for a better treatment.