Lost in Nucleocytoplasmic Transportation: New Insights Into FUS-Mediated Neurodegeneration

• Main Author: Lin, Yen-Chen
• Format: Others
• Published: eScholarship@UMMS 2020
• Subjects: ALS; nuclear pore; RNA-binding protein; neurodegeneration; nucleocytoplasmic transport; FUS; Molecular and Cellular Neuroscience
• Online Access: https://escholarship.umassmed.edu/gsbs_diss/1107; https://escholarship.umassmed.edu/cgi/viewcontent.cgi?article=2116&context=gsbs_diss

Nucleocytoplasmic transport (NCT) declines during aging and in the context of age-dependent neurodegenerative diseases. However, the mechanisms underlying NCT decline in the disease are poorly understood. FUS is an RNA binding protein that shuttles between the nucleus and cytoplasm and is actively involved in NCT. Mutations in FUS cause amyotrophic lateral sclerosis (ALS), a fatal and incurable motor neuron disorder. We sought to understand the disease mechanism underlying FUS-induced NCT decline in ALS. Here, I uncovered NCT-related defects in motor neurons derived from human induced pluripotent stem cells (iPSCs) harboring an ALS-linked FUS mutation. Importantly, these NCT defects were rescued by genetically correcting the FUS mutation in iPSCs. To gain insight into how expression of mutant FUS causes nuclear pore defects, I demonstrated an altered localization where FUS and nucleoporins (Nups) interact in situ within patient-derived human neurons. Moreover, FUS became aggregation-prone when interacting with Nup62 in vitro, and RNA further alleviated their aggregation propensity. Importantly, NCT-related defects and neuronal toxicity induced by ALS-FUS were ameliorated by modulating Nup expression in vivo. Collectively, these findings implicate aberrant Nup interactions in the pathogenic mechanism of ALS-FUS, and direct targeting the gain-of-function protein interactions could be therapeutic for multiple causes of neurodegeneration.