RANBP17 Overexpression Restores Nucleocytoplasmic Transport and Ameliorates Neurodevelopment in Induced DYT1 Dystonia Motor Neurons.

DYT1 dystonia is a debilitating neurological movement disorder, and it represents the most frequent and severe form of hereditary primary dystonia. There is currently no cure for this disease due to its unclear pathogenesis. In our previous study utilizing patient-specific motor neurons (MNs), we identified distinct cellular deficits associated with the disease, including a deformed nucleus, disrupted neurodevelopment, and compromised nucleocytoplasmic transport (NCT) functions. However, the precise molecular mechanisms underlying these cellular impairments have remained elusive. In this study, we revealed the genome-wide changes in gene expression in DYT1 MNs through transcriptomic analysis. We found that those dysregulated genes are intricately involved in neurodevelopment and various biological processes. Interestingly, we identified that the expression level of RANBP17, a RAN-binding protein crucial for NCT regulation, exhibited a significant reduction in DYT1 MNs. By manipulating RANBP17 expression, we further demonstrated that RANBP17 plays an important role in facilitating the nuclear transport of both protein and transcript cargos in induced human neurons. Excitingly, the overexpression of RANBP17 emerged as a substantial mitigating factor, effectively restoring impaired NCT activity and rescuing neurodevelopmental deficits observed in DYT1 MNs. These findings shed light on the intricate molecular underpinnings of impaired NCT in DYT1 neurons and provide novel insights into the pathophysiology of DYT1 dystonia, potentially leading to the development of innovative treatment strategies.

Protocol to image and quantify nucleocytoplasmic transport in cultured cells using fluorescent in situ hybridization and a dual reporter system.

Nucleocytoplasmic transport (NCT) plays critical roles in maintaining cellular homeostasis. Here, we present a protocol to measure NCT for both transcript and protein cargos in cultured cells. We first describe the fluorescent in situ hybridization (FISH) assay to measure the nuclear mRNA export. We then detail a dual reporter system to measure the protein NCT. This protocol also includes image analysis and data output using CellProfiler™. The combined approach can be used to unbiasedly analyze NCT activities in cultured cells. For complete details on the use and execution of this protocol, please refer to Ding et al. (2020, 2021).

Generation of highly pure motor neurons from human induced pluripotent stem cells.

Generation of human motor neurons (MNs) overcomes the inaccessibility to patient brain tissues and greatly facilitates the research in MN-related diseases. Here, we describe a protocol for generation of neural progenitor cells (NPCs) from human induced pluripotent stem cells (hiPSCs), followed by preparation of functional MNs. The optimized induction condition with the expression of three transcription factors in a single lentiviral vector significantly improved the yield and purity, making it possible to biochemically identify dysregulated factors in diseased neurons. For complete details on the use and execution of this protocol, please refer to Ding (2021), Ding et al. (2021), and Sepehrimanesh and Ding (2020).