scholarly journals Stress-Specific Spatiotemporal Responses of RNA-Binding Proteins in Human Stem Cell-Derived Motor Neurons

2020 ◽  
Vol 21 (21) ◽  
pp. 8346
Author(s):  
Jasmine Harley ◽  
Rickie Patani

RNA-binding proteins (RBPs) have been shown to play a key role in the pathogenesis of a variety of neurodegenerative disorders. Amyotrophic lateral sclerosis (ALS) is an exemplar neurodegenerative disease characterised by rapid progression and relatively selective motor neuron loss. Nuclear-to-cytoplasmic mislocalisation and accumulation of RBPs have been identified as a pathological hallmark of the disease, yet the spatiotemporal responses of RBPs to different extrinsic stressors in human neurons remain incompletely understood. Here, we used healthy induced pluripotent stem cell (iPSC)-derived motor neurons to model how different types of cellular stress affect the nucleocytoplasmic localisation of key ALS-linked RBPs. We found that osmotic stress robustly induced nuclear loss of TDP-43, SPFQ, FUS, hnRNPA1 and hnRNPK, with characteristic changes in nucleocytoplasmic localisation in an RBP-dependent manner. Interestingly, we found that RBPs displayed stress-dependent characteristics, with unique responses to both heat and oxidative stress. Alongside nucleocytoplasmic protein distribution changes, we identified the formation of stress- and RBP-specific nuclear and cytoplasmic foci. Furthermore, the kinetics of nuclear relocalisation upon recovery from extrinsic stressors was also found to be both stress- and RBP-specific. Importantly, these experiments specifically highlight TDP-43 and FUS, two of the most recognised RBPs in ALS pathogenesis, as exhibiting delayed nuclear relocalisation following stress in healthy human motor neurons as compared to SFPQ, hnRNPA1 and hnRNPK. Notably, ALS-causing valosin containing protein (VCP) mutations did not disrupt the relocalisation dynamics of TDP-43 or FUS in human motor neurons following stress. An increased duration of TDP-43 and FUS within the cytoplasm after stress may render the environment more aggregation-prone, which may be poorly tolerated in the context of ALS and related neurodegenerative disorders. In summary, our study addresses stress-specific spatiotemporal responses of neurodegeneration-related RBPs in human motor neurons. The insights into the nucleocytoplasmic dynamics of RBPs provided here may be informative for future studies examining both disease mechanisms and therapeutic strategy.

PLoS Genetics ◽  
2014 ◽  
Vol 10 (11) ◽  
pp. e1004797 ◽  
Author(s):  
Di Chen ◽  
Chan Wu ◽  
Shaowei Zhao ◽  
Qing Geng ◽  
Yu Gao ◽  
...  

2021 ◽  
Vol 15 ◽  
Author(s):  
Benjamin L. Zaepfel ◽  
Jeffrey D. Rothstein

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease that affects upper and lower motor neurons. Familial ALS accounts for a small subset of cases (<10–15%) and is caused by dominant mutations in one of more than 10 known genes. Multiple genes have been causally or pathologically linked to both ALS and frontotemporal dementia (FTD). Many of these genes encode RNA-binding proteins, so the role of dysregulated RNA metabolism in neurodegeneration is being actively investigated. In addition to defects in RNA metabolism, recent studies provide emerging evidence into how RNA itself can contribute to the degeneration of both motor and cortical neurons. In this review, we discuss the roles of altered RNA metabolism and RNA-mediated toxicity in the context of TARDBP, FUS, and C9ORF72 mutations. Specifically, we focus on recent studies that describe toxic RNA as the potential initiator of disease, disease-associated defects in specific RNA metabolism pathways, as well as how RNA-based approaches can be used as potential therapies. Altogether, we highlight the importance of RNA-based investigations into the molecular progression of ALS, as well as the need for RNA-dependent structural studies of disease-linked RNA-binding proteins to identify clear therapeutic targets.


2019 ◽  
Vol 97 (1) ◽  
pp. 10-20 ◽  
Author(s):  
Laura P.M.H. de Rooij ◽  
Derek C.H. Chan ◽  
Ava Keyvani Chahi ◽  
Kristin J. Hope

Normal hematopoiesis is sustained through a carefully orchestrated balance between hematopoietic stem cell (HSC) self-renewal and differentiation. The functional importance of this axis is underscored by the severity of disease phenotypes initiated by abnormal HSC function, including myelodysplastic syndromes and hematopoietic malignancies. Major advances in the understanding of transcriptional regulation of primitive hematopoietic cells have been achieved; however, the post-transcriptional regulatory layer that may impinge on their behavior remains underexplored by comparison. Key players at this level include RNA-binding proteins (RBPs), which execute precise and highly coordinated control of gene expression through modulation of RNA properties that include its splicing, polyadenylation, localization, degradation, or translation. With the recent identification of RBPs having essential roles in regulating proliferation and cell fate decisions in other systems, there has been an increasing appreciation of the importance of post-transcriptional control at the stem cell level. Here we discuss our current understanding of RBP-driven post-transcriptional regulation in HSCs, its implications for normal, perturbed, and malignant hematopoiesis, and the most recent technological innovations aimed at RBP–RNA network characterization at the systems level. Emerging evidence highlights RBP-driven control as an underappreciated feature of primitive hematopoiesis, the greater understanding of which has important clinical implications.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Barbara Celona ◽  
John von Dollen ◽  
Sarat C Vatsavayai ◽  
Risa Kashima ◽  
Jeffrey R Johnson ◽  
...  

Expanded GGGGCC repeats in the first intron of the C9orf72 gene represent the most common cause of familial amyotrophic lateral sclerosis (ALS), but the mechanisms underlying repeat-induced disease remain incompletely resolved. One proposed gain-of-function mechanism is that repeat-containing RNA forms aggregates that sequester RNA binding proteins, leading to altered RNA metabolism in motor neurons. Here, we identify the zinc finger protein Zfp106 as a specific GGGGCC RNA repeat-binding protein, and using affinity purification-mass spectrometry, we show that Zfp106 interacts with multiple other RNA binding proteins, including the ALS-associated factors TDP-43 and FUS. We also show that Zfp106 knockout mice develop severe motor neuron degeneration, which can be suppressed by transgenic restoration of Zfp106 specifically in motor neurons. Finally, we show that Zfp106 potently suppresses neurotoxicity in a Drosophila model of C9orf72 ALS. Thus, these studies identify Zfp106 as an RNA binding protein with important implications for ALS.


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Nandini Ramesh ◽  
Elizabeth L. Daley ◽  
Amanda M. Gleixner ◽  
Jacob R. Mann ◽  
Sukhleen Kour ◽  
...  

Abstract The most common genetic cause of amyotrophic lateral sclerosis (ALS) is a GGGGCC (G4C2) hexanucleotide repeat expansions in first intron of the C9orf72 gene. The accumulation of repetitive RNA sequences can mediate toxicity potentially through the formation of intranuclear RNA foci that sequester key RNA-binding proteins (RBPs), and non-ATG mediated translation into toxic dipeptide protein repeats. However, the contribution of RBP sequestration to the mechanisms underlying RNA-mediated toxicity remain unknown. Here we show that the ALS-associated RNA-binding protein, Matrin-3 (MATR3), colocalizes with G4C2 RNA foci in patient tissues as well as iPSC-derived motor neurons harboring the C9orf72 mutation. Hyperexpansion of C9 repeats perturbed subcellular distribution and levels of endogenous MATR3 in C9-ALS patient-derived motor neurons. Interestingly, we observed that ectopic expression of human MATR3 strongly mitigates G4C2-mediated neurodegeneration in vivo. MATR3-mediated suppression of C9 toxicity was dependent on the RNA-binding domain of MATR3. Importantly, we found that expression of MATR3 reduced the levels of RAN-translation products in mammalian cells in an RNA-dependent manner. Finally, we have shown that knocking down endogenous MATR3 in C9-ALS patient-derived iPSC neurons decreased the presence of G4C2 RNA foci in the nucleus. Overall, these studies suggest that MATR3 genetically modifies the neuropathological and the pathobiology of C9orf72 ALS through modulating the RNA foci and RAN translation.


2013 ◽  
Vol 201 (3) ◽  
pp. 361-372 ◽  
Author(s):  
Yun R. Li ◽  
Oliver D. King ◽  
James Shorter ◽  
Aaron D. Gitler

Amyotrophic lateral sclerosis (ALS) is a fatal human neurodegenerative disease affecting primarily motor neurons. Two RNA-binding proteins, TDP-43 and FUS, aggregate in the degenerating motor neurons of ALS patients, and mutations in the genes encoding these proteins cause some forms of ALS. TDP-43 and FUS and several related RNA-binding proteins harbor aggregation-promoting prion-like domains that allow them to rapidly self-associate. This property is critical for the formation and dynamics of cellular ribonucleoprotein granules, the crucibles of RNA metabolism and homeostasis. Recent work connecting TDP-43 and FUS to stress granules has suggested how this cellular pathway, which involves protein aggregation as part of its normal function, might be coopted during disease pathogenesis.


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