Linhart Radek, Wong Sarah Anne, Cao Jieyun, Tran Melody, Huynh Anne, Ardrey Casey, Park Jong Min, Hsu Christine, Taha Saher, Peterson Rentia, Shea Shannon, Kurian Jason, Venderova Katerina
Department of Physiology and Pharmacology, Thomas J, Long School of Pharmacy and Health Sciences, University of the Pacific, 751 Brookside Rd, Stockton, CA 95211, USA.
Mol Neurodegener. 2014 Jun 11;9:23. doi: 10.1186/1750-1326-9-23.
Parkinson's disease (PD) is the most common movement neurodegenerative movement disorder. An incomplete understanding of the molecular pathways involved in its pathogenesis impedes the development of effective disease-modifying treatments. To address this gap, we have previously generated a Drosophila model of PD that overexpresses PD pathogenic mutant form of the second most common causative gene of PD, Leucine-Rich Repeat Kinase 2 (LRRK2).
We employed this model in a genetic modifier screen and identified a gene that encodes for a core subunit of retromer - a complex essential for the sorting and recycling of specific cargo proteins from endosomes to the trans-Golgi network and cell surface. We present evidence that overexpression of the Vps35 or Vps26 component of the cargo-recognition subunit of the retromer complex ameliorates the pathogenic mutant LRRK2 eye phenotype. Furthermore, overexpression of Vps35 or Vps26 significantly protects from the locomotor deficits observed in mutant LRRK2 flies, as assessed by the negative geotaxis assay, and rescues their shortened lifespan. Strikingly, overexpressing Vps35 alone protects from toxicity of rotenone, a neurotoxin commonly used to model parkinsonism, both in terms of lifespan and locomotor activity of the flies, and this protection is sustained and even augmented in the presence of mutant LRRK2. Finally, we demonstrate that knocking down expression of Vps35 in dopaminergic neurons causes a significant locomotor impairment.
From these results we conclude that LRRK2 plays a role in the retromer pathway and that this pathway is involved in PD pathogenesis.
帕金森病（PD）是最常见的运动性神经退行性运动障碍。对其发病机制中涉及的分子途径的不完全理解阻碍了有效的疾病修饰治疗的发展。为了填补这一空白，我们之前构建了一种PD果蝇模型，该模型过表达PD第二常见致病基因富含亮氨酸重复激酶2（LRRK2）的致病突变形式。
我们在基因修饰筛选中使用了该模型，并鉴定出一个编码逆转录酶核心亚基的基因，逆转录酶是一种将特定货物蛋白从内体分类并循环至反式高尔基体网络和细胞表面所必需的复合物。我们提供的证据表明，逆转录酶复合物货物识别亚基的Vps35或Vps26组分的过表达改善了致病突变型LRRK2的眼部表型。此外，通过负趋地性试验评估，Vps35或Vps26的过表达显著保护突变型LRRK2果蝇免受运动功能缺陷的影响，并挽救它们缩短的寿命。引人注目的是，单独过表达Vps35可保护果蝇免受鱼藤酮（一种常用于模拟帕金森症的神经毒素）的毒性影响，无论是在寿命还是运动活性方面，并且在存在突变型LRRK2的情况下这种保护作用持续存在甚至增强。最后，我们证明在多巴胺能神经元中敲低Vps35的表达会导致显著的运动功能障碍。
从这些结果我们得出结论，LRRK2在逆转录酶途径中起作用，并且该途径参与PD发病机制。
