TDP-43 self-interaction is modulated by redox-active compounds Auranofin, Chelerythrine and Riluzole

David Larbi Simpong,Michael Schaefer,Nicole Urban,Max Holzer,Jens Stieler,Moritz Oberstadt,Ute Römuß,Thomas Arendt

doi:10.1038/s41598-018-20565-0

David Larbi Simpong, Michael Schaefer + Show 6 more

Open Access

https://doi.org/10.1038/s41598-018-20565-0

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Journal: Scientific Reports	Publication Date: Feb 2, 2018
Citations: 25	License type: open-access

Affiliation: Leipzig University

Abstract

Amyotrophic lateral sclerosis (ALS) represents a fatal neurodegenerative disease, which is characterized by a rapid loss of lower and upper motor neurons. As a major neuropathological hallmark, protein aggregates containing the Transactivating Response Region (TAR) DNA Binding Protein (TDP-43) are detectable in about 95% of sporadic ALS patients. TDP-43 interacts with itself physiologically to form liquid droplets, which may progress to pathological aggregates. In this study, we established the NanoBit luciferase complementation assay to measure TDP-43 self-interaction and found the fusion of the split luciferase subunits to the N-terminus of the protein as the strongest interacting partners. A screen of pharmacologically active compounds from the LOPAC®1280 library identified auranofin, chelerythrine and riluzole as dose-dependent inhibitors of TDP-43 self-interaction. Further analysis of drug action of the gold-containing thioredoxin reductase inhibitor auranofin revealed a redistribution from insoluble TDP-43 protein pool to PBS-soluble protein pool in N2a cells. In addition, auranofin treatment diminished reduced glutathione as a sign for oxidative modulation.

Highlights

A screen of pharmacologically active compounds from the LOPAC®1280 library identified auranofin, chelerythrine and riluzole as dose-dependent inhibitors of TDP-43 self-interaction
TDP-43 is a major component of cytoplasmic proteinaceous aggregates and detectable in about 95% of sporadic Amyotrophic lateral sclerosis (ALS) patients[6,7]
TDP-43 aggregation is seen as a neuropathological hallmark of ALS4

Summary

Introduction

A screen of pharmacologically active compounds from the LOPAC®1280 library identified auranofin, chelerythrine and riluzole as dose-dependent inhibitors of TDP-43 self-interaction. As a neuropathological hallmark of ALS, protein aggregates have been found in motor neurons of ALS patients which contain a variety of proteins like profilin 1 or peripherin involved in different cellular functions like the intracellular transport or the cytoskeleton architecture[4,5]. TDP-43 is a multidomain protein containing a folded, multimer-forming N-terminal domain[8,9], tandem RNA recognition motif (RRM) domains that bind (UG)-rich sequences[10], and a C-terminal domain (CTD) that is essential for heterogeneous ribonucleoprotein particle (hnRNP) interactions and splicing activity[11]. Several protein regions of TDP-43 like N-terminus, RNA recognition motif (RRM) domains and C-terminus are involved in the aggregation process[11,16,17]. We found the highest self-interaction potential of constructs pFN33_TDP-43 and pFN35_TDP43 with each of the NanoBit subunits fused to the N-terminal site of TDP-43 having a parallel TDP-43 orientation and allowing an undisturbed self-interaction of other regions like RRM domains or C–terminus of

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