TDP-43 pathology disrupts nuclear pore complexes and nucleocytoplasmic transport in ALS/FTD

Chung Chuan Chou ,Maureen A Powers,Yu Han Chen,Nicholas T Seyfried,Rosa Rademakers,Leonard Petrucelli,Yong Jie Zhang ,Melissa Sayegh,Ileana Lorenzini,Rita Sattler,Thomas Kukar,Yi Zhang,Duc M Duong,Nigel J Cairns,Feilin Liu,Mfon Umoh ,Daniela C Zarnescu,Chadwick M Hales,Kevin B Boylan,Spencer Vaughan ,Paul G Donlin-Asp,Jonathan D Glass,Marla Gearing,Dennis W Dickson,Wilfried Rossoll

doi:10.1038/s41593-017-0047-3

Abstract

The cytoplasmic mislocalization and aggregation of TAR DNA-binding protein-43 (TDP-43) is a common histopathological hallmark of the amyotrophic lateral sclerosis and frontotemporal dementia disease spectrum (ALS/FTD). However, the composition of aggregates and their contribution to the disease process remain unknown. Here we used proximity-dependent biotin identification (BioID) to interrogate the interactome of detergent-insoluble TDP-43 aggregates and found them enriched for components of the nuclear pore complex and nucleocytoplasmic transport machinery. Aggregated and disease-linked mutant TDP-43 triggered the sequestration and/or mislocalization of nucleoporins and transport factors, and interfered with nuclear protein import and RNA export in mouse primary cortical neurons, human fibroblasts and induced pluripotent stem cell–derived neurons. Nuclear pore pathology is present in brain tissue in cases of sporadic ALS and those involving genetic mutations in TARDBP and C9orf72. Our data strongly implicate TDP-43-mediated nucleocytoplasmic transport defects as a common disease mechanism in ALS/FTD.

Highlights

The cytoplasmic mislocalization and aggregation of TAR DNA-binding protein-43 (TDP-43) is a common histopathological hallmark of the amyotrophic lateral sclerosis and frontotemporal dementia disease spectrum (ALS/FTD)
To characterize changes in the interaction partners of TDP-43 under normal and pathological conditions, we used the biotin identification (BioID) approach, which is based on the fusion of a promiscuous mutant of Escherichia coli biotin ligase (BirA*) to proteins of interest and catalyzes the biotinylation of proximate proteins in the natural cellular environment[12,13]
Biotinylated proteins colocalized with myc-BirA*TDP-43 in the nucleus and with myc-BirA*-TDP-C-terminal fragment (CTF) in cytoplasmic aggregates that were positive for hyperphosphorylated TDP-43, ubiquitin and p62/SQSTM1 (Fig. 1c and Supplementary Fig. 1c,d)

Summary

Introduction

The cytoplasmic mislocalization and aggregation of TAR DNA-binding protein-43 (TDP-43) is a common histopathological hallmark of the amyotrophic lateral sclerosis and frontotemporal dementia disease spectrum (ALS/FTD). A common histopathological hallmark in ALS/FTD patient brains is the cytoplasmic mislocalization of the predominately nuclear RNA-binding TDP-43 and the accumulation of its hyperphosphorylated and ubiquitinated C-terminal fragment (CTF) in detergent-insoluble aggregates[2,3]. This pathology is observed in ~97% of ALS and ~50% of FTD cases, and frequently present in other neurodegenerative diseases[1]. Our findings of Nup[205] pathology in brain tissue from sporadic ALS (sALS) and TARDBP mutation-associated ALS (TDP-ALS) point to nucleocytoplasmic transport defects caused by TDP-43 pathology as a common disease mechanism in ALS/FTD, and potentially other TDP-43 proteinopathies

Methods

Results

Conclusion