TDP-43 oligomerization and RNA binding are codependent but their loss elicits distinct pathologies

Pérez‐Berlanga, Manuela; Wiersma, Vera I.; Zbinden, Aurélie; Vos, Laura De; Wagner, Ulrich; Foglieni, Chiara; Mallona, Izaskun; Betz, Katharina M.; Cléry, Antoine; Weber, Julien; Guo, Zhongning; Rigort, Ruben; Rossi, Pierre De; Manglunia, Ruchi; Tantardini, Elena; Sahadevan, Sonu; Stach, Oliver; Hruška-Plocháň, Marián; Allain, Frédéric; Paganetti, Paolo; Polymenidou, Magdalini

doi:10.1101/2022.05.23.493029

Cited by 4 publications

(5 citation statements)

References 101 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Introductionmentioning

confidence: 99%

“…RNA deficiency promotes TDP-43 instability [26,27], and aberrant liquid-liquid phase separation (LLPS), forming assemblies which may seed pathological aggregation [25,[28][29][30][31][32][33][34]. TDP-43 LLPS occurs physiologically, but can be enhanced in response to cellular stress or RNA dyshomeostasis, giving rise to diverse biomolecular condensates, characterised by 'liquid droplet-like' properties of subcellular mobility, fusion, fission, and dynamic exchange of comprising proteins with surrounding intracellular TDP-43 [25,28,30,32,33,[35][36][37][38]. The effects of RNA binding on TDP-43 assembly and aggregation, independent of other pathological modifications, have been studied using TDP-43 'FL' mutants in which 4 or 5 essential RNA-binding phenylalanine residues in the RRMs are mutated to leucine, preventing RNA interactions [21,25,31,39,40].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Aggregation-prone TDP-43 sequesters and drives pathological transitions of free nuclear TDP-43

Keating

Bademosi

Gil

et al. 2023

Cell. Mol. Life Sci.

View full text Add to dashboard Cite

Aggregation of the RNA-binding protein, TDP-43, is the unifying hallmark of amyotrophic lateral sclerosis and frontotemporal dementia. TDP-43-related neurodegeneration involves multiple changes to normal physiological TDP-43, which undergoes nuclear depletion, cytoplasmic mislocalisation, post-translational modification, and aberrant liquid–liquid phase separation, preceding inclusion formation. Along with toxic cytoplasmic aggregation, concurrent depletion and dysfunction of normal nuclear TDP-43 in cells with TDP-43 pathology is likely a key potentiator of neurodegeneration, but is not well understood. To define processes driving TDP-43 dysfunction, we used CRISPR/Cas9-mediated fluorescent tagging to investigate how disease-associated stressors and pathological TDP-43 alter abundance, localisation, self-assembly, aggregation, solubility, and mobility dynamics of normal nuclear TDP-43 over time in live cells. Oxidative stress stimulated liquid–liquid phase separation of endogenous TDP-43 into droplet-like puncta, or spherical shell-like anisosomes. Further, nuclear RNA-binding-ablated or acetylation-mimicking TDP-43 readily sequestered and depleted free normal nuclear TDP-43 into dynamic anisosomes, in which recruited endogenous TDP-43 proteins remained soluble and highly mobile. Large, phosphorylated inclusions formed by nuclear or cytoplasmic aggregation-prone TDP-43 mutants also caused sequestration, but rendered endogenous TDP-43 immobile and insoluble, indicating pathological transition. These findings suggest that RNA-binding deficiency and post-translational modifications including acetylation exacerbate TDP-43 aggregation and dysfunction by driving sequestration, mislocalisation, and depletion of normal nuclear TDP-43 in neurodegenerative diseases.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aggregation-prone TDP-43 sequesters and drives pathological transitions of free nuclear TDP-43

Keating

Bademosi

Gil

et al. 2023

Cell. Mol. Life Sci.

View full text Add to dashboard Cite

show abstract

“…Crucially, our unbiased quantitative image analysis demonstrated direct correlations between mutant TDP-43 aggregation and the sequestration and depletion of free normal nuclear endogenous TDP-43, which was amplified by acetylated or RNA-binding-ablated TDP-43 mutants. While previous studies indicate that loss of RNA-binding promotes aberrant TDP-43 self-assembly and aggregation (Pérez-Berlanga et al, 2022), others suggest that TDP-43-RNA interactions mediate such sequestration, as RNA-binding ablated 4FL mutants were shown to not co-precipitate with endogenous TDP-43 (Che et al, 2015; Jiang et al, 2022). However, our results indicate that RNA-binding function is not necessary for sequestration of normal TDP-43.…”

Section: Discussionmentioning

confidence: 97%

“…Loss of TDP-43 RNA-binding capacity, through RRM mutation or acetylation, thereby promotes aberrant self-assembly and pathological aggregation (Chen et al, 2019; Gasset-Rosa et al, 2019; Hallegger et al, 2021; Maharana et al, 2018; Mann et al, 2019; McGurk et al, 2018; Pérez-Berlanga et al, 2022; Yu et al, 2021). This is further supported by findings that TDP-43 species lacking RRMs, or containing ALS-associated RRM mutations, demonstrate high aggregation propensity and toxicity (Shenoy et al, 2020; Wei et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

RNA-deficient TDP-43 causes loss of free nuclear TDP-43 by sequestration

Keating

Bademosi

Gil

et al. 2022

Preprint

View full text Add to dashboard Cite

Dysfunction and aggregation of the RNA-binding protein, TDP-43, is the unifying hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Mechanisms and relative contributions of concurrent TDP-43 nuclear depletion, cytoplasmic accumulation, and post-translational modification to neurodegeneration remain unresolved. We employed CRISPR/Cas9-mediated fluorescent tagging to investigate how disease-associated stressors and pathological TDP-43 alter abundance, localisation, self-assembly, aggregation, solubility, and mobility dynamics of endogenous TDP-43 over time. Oxidative stress stimulated TDP-43 liquid-liquid phase separation into droplets or spherical shell-like 'anisosomes', which were not formed by over-expressed wild-type TDP-43. Further, nuclear RNA-binding-ablated or acetylation-mimicking TDP-43 rapidly formed anisosomes and inclusions that readily sequestered and depleted free normal nuclear TDP-43. The majority of total endogenous TDP-43 was sequestered into anisosomes, but retained high protein mobility and solubility. However, cytoplasmic RNA-deficient TDP-43 formed large phosphorylated inclusions that occasionally sequestered endogenous TDP-43, rendering it insoluble and immobile, indicating irreversible pathological transition. These findings suggest that post-translational modification and RNA-binding deficiency exacerbate TDP-43 aggregation and dysfunction by driving sequestration, mislocalisation, and depletion of normal nuclear TDP-43 in ALS and FTD.

show abstract

“…In HD, TDP-43 can co-localize with HTT EM48 positive intracellular inclusions 20 , and was found to promote somatic CAG repeat expansion in HD mouse model 18 . Loss of nuclear TDP-43 results in abnormal splicing events 23,32,33 including the aberrant inclusion of cryptic exons [34][35][36][37][38] . It is not known whether HD-associated expression and splicing alterations are related to TDP-43 disruption in HD.…”

Section: Main Textmentioning

confidence: 99%

Aberrant splicing in Huntington’s disease via disrupted TDP-43 activity accompanied by altered m6A RNA modification

Nguyen,

Miramontes,

Chillon-Marinas

et al. 2023

Preprint

View full text Add to dashboard Cite

Huntington’s disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the first exon of theHTTgene encoding huntingtin. Prior reports have established a correlation between CAG expandedHTTand altered gene expression. However, the mechanisms leading to disruption of RNA processing in HD remain unclear. Here, our analysis of the reported HTT protein interactome identifies interactions with known RNA-binding proteins (RBPs). Total, long-read sequencing and targeted RASL-seq of RNAs from cortex and striatum of the HD mouse model R6/2 reveals increased exon skipping which is confirmed in Q150 and Q175 knock-in mice and in HD human brain. We identify the RBP TDP-43 and the N6-methyladenosine (m6A) writer protein methyltransferase 3 (METTL3) to be upstream regulators of exon skipping in HD. Along with this novel mechanistic insight, we observe decreased nuclear localization of TDP-43 and cytoplasmic accumulation of phosphorylated TDP-43 in HD mice and human brain. In addition, TDP-43 co-localizes with HTT in human HD brain forming novel nuclear aggregate-like bodies distinct from mutant HTT inclusions or previously observed TDP-43 pathologies. Binding of TDP-43 onto RNAs encoding HD-associated differentially expressed and aberrantly spliced genes is decreased. Finally, m6A RNA modification is reduced on RNAs abnormally expressed in striatum from HD R6/2 mouse brain, including at clustered sites adjacent to TDP-43 binding sites. Our evidence supports TDP-43 loss of function coupled with altered m6A modification as a novel mechanism underlying alternative splicing/unannotated exon usage in HD and highlights the critical nature of TDP-43 function across multiple neurodegenerative diseases.

show abstract

TDP-43 oligomerization and RNA binding are codependent but their loss elicits distinct pathologies

Cited by 4 publications

References 101 publications

Aggregation-prone TDP-43 sequesters and drives pathological transitions of free nuclear TDP-43

Aggregation-prone TDP-43 sequesters and drives pathological transitions of free nuclear TDP-43

RNA-deficient TDP-43 causes loss of free nuclear TDP-43 by sequestration

Aberrant splicing in Huntington’s disease via disrupted TDP-43 activity accompanied by altered m6A RNA modification

Contact Info

Product

Resources

About