A genome-wide RNA interference screening reveals protectiveness of SNX5 knockdown in a Parkinson’s disease cell model

Abstract

AbstractBackgroundAlpha-synuclein is a major player in the pathophysiology of a group of diseases called synucleinopathies, which include Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy. To date, there is no disease-modifying therapy available for these synucleinopathies. Furthermore, the intracellular mechanisms by which alpha-synuclein confers toxicity are not yet fully understood. Therefore, it is of utmost importance to investigate the pathophysiology of alpha-synuclein-induced toxicity in order to identify novel molecular targets for the development of disease-modifying therapies.MethodsIn the present study, we performed the first genome-wide siRNA modifier screening in a human postmitotic neuronal cell model using alpha-synuclein-induced toxicity as read-out. In a multi-step approach, we identified several genes, whose knockdown protected from alpha-synuclein-induced toxicity. The main hit was further validated by different methods, including immunofluorescence microscopy, qPCR, and Western blot.ResultsThe highest protection was achieved by knockdown ofSNX5, which encodes the SNX5 protein, a component of the retromer complex. We confirmed the protective efficacy ofSNX5knockdown with an independent siRNA system. SNX5 protein is part of SNX-BAR heterodimers, which are part of the retromer complex. We found that extracellular and overexpressed intracellular alpha-synuclein led to fragmentation of the trans-Golgi network, which was prevented bySNX5knockdown by confining alpha-synuclein in early endosomes.ConclusionIn summary, our data suggest that SNX5 plays an important role in trafficking and toxicity of alpha-synuclein. Therefore, SNX5 appears to be a possible target for therapeutic interventions in synucleinopathies.