Small heat shock protein HSPB8 interacts with a pre-fibrillar TDP43 low complexity domain species to delay fibril formation

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 30, 2025

The loss of cellular proteostasis through aberrant stress granule formation is implicated in neurodegenerative diseases. Stress granules are formed by biomolecular condensation involving protein-protein and protein-RNA interactions. These assemblies protective, but can rigidify, leading to amyloid-like fibril formation, a hallmark the disease pathology. Key proteins dictating disassembly, such as TDP43, contain low-complexity (LC) domains that drive formation. HSPB8, small heat shock protein, plays critical role modulating fluidity, preventing aggregation promoting degradation misfolded proteins. We examined interaction between HSPB8 TDP43 LC using thioflavin T (ThT) fluorescence polarization (FP) assays, microscopy photobleaching experiments, crosslinking mass spectrometry (XL-MS). Our results indicate delays domain-specific interactions with nucleating species, without affecting elongation rates. findings provide mechanistic insight into how ATP-independent chaperones mediate domain basis for investigating subverts chaperone activity disease. facilitate clearance aggregated autophagy. This study provides molecular mechanism which interact aggregation-prone low complexity protein RNA-binding linked pathologies. foundation designing improved therapeutics illustrate methodology identify regions targeted drug development context

Language: Английский

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TDP-43 seeding induces cytoplasmic aggregation heterogeneity and nuclear loss of function of TDP-43

Neuron, Journal Year: 2025, Volume and Issue: unknown

Published: March 1, 2025

Cytoplasmic aggregation and nuclear depletion of TAR DNA-binding protein 43 (TDP-43) are hallmarks several neurodegenerative disorders. Yet, recapitulating both features in cellular systems has been challenging. Here, we produced amyloid-like fibrils from recombinant TDP-43 low-complexity domain demonstrate that sonicated trigger pathology human cells, including induced pluripotent stem cell (iPSC)-derived neurons. Fibril-induced cytoplasmic inclusions acquire distinct biophysical properties, recapitulate pathological such as phosphorylation, ubiquitin, p62 accumulation, recruit endogenous TDP-43, leading to its loss function. A transcriptomic signature linked disease-specific cryptic splicing, is identified. aggregates exhibit time-dependent heterogeneous morphologies observed patients-including compacted, filamentous, or fragmented-which involve upregulation/recruitment clearance pathways. Ultimately, cell-specific progressive toxicity provoked by seeded These findings identify TDP-43-templated a key mechanism driving gain function function, offering valuable approach modifiers sporadic proteinopathies.

Language: Английский

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Membrane Charge Drives the Aggregation of TDP-43 Pathological Fragments

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: April 8, 2025

TDP-43 protein is an RNA-binding linked to amyotrophic lateral sclerosis, frontotemporal dementia, and Alzheimer disease. While normally a that shuttles between the nucleus cytoplasm, has recently been found also in extracellular vesicles. These are important medium for cell-cell communication allows transfer of lipids, proteins, genetic material among cells. An increasing concern neurodegenerative diseases, however, possibility vesicles can provide effective way spread misfolded proteins could "infect" other cells according "prion-like" mechanism. To characterize interaction with lipid membranes, we carried out systematic biophysical study using fragment lacking first 84 N-terminal residues, called M85, synthetic model phospholipid membranes. We utilized standard techniques, such as fluorescence microscopy, complemented by neutron reflectivity measurements. Our results show charge affects modality which M85 interacts membranes: higher negative induces bind bilayer surface, promoting aggregation decreasing damage this causes. Thus, speculate M85-lipid membrane play previously undefined role TDP-43-related diseases.

Language: Английский

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Inhibitor-based modulation of huntingtin aggregation mechanisms mitigates fibril-induced cellular stress

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: April 15, 2025

Abstract Huntington’s disease (HD) is a neurodegenerative disorder in which mutated fragments of the huntingtin protein (Htt) undergo misfolding and aggregation. Since aggregated proteins can cause cellular stress cytotoxicity, there an interest development small molecule aggregation inhibitors as potential modulators HD pathogenesis. Here, we study how polyphenol modulates mechanism exon 1 (HttEx1) even at sub-stoichiometric ratios. Sub-stoichiometric amounts curcumin impacted primary and/or secondary nucleation events, extending pre-aggregation lag phase. Remarkably, disrupted process changed both aggregate structure its cell metabolic properties. When administered to neuronal cells, ‘break-through’ aggregates induced significantly reduced compared formed absence inhibitors. Structural analysis by electron microscopy, angle X-ray scattering (SAXS), solid-state NMR spectroscopy identified changes fibril structures, probing flanking domains fuzzy coat core. We propose that latter relate presence or polyglutamine (polyQ) β-hairpin structures. Our findings highlight multifaceted consequences modulate landscape, with implications for treatment strategies other amyloid disorders.

Language: Английский

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Optogenetic induction of TDP-43 aggregation impairs neuronal integrity and behavior in Caenorhabditis elegans

Translational Neurodegeneration, Journal Year: 2025, Volume and Issue: 14(1)

Published: April 16, 2025

Abstract Background Cytoplasmic aggregation of TAR DNA binding protein 43 (TDP-43) in neurons is one the hallmarks TDP-43 proteinopathy. Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are closely associated with proteinopathy; however, it remains uncertain whether initiates pathology or a consequence it. Methods To demonstrate aggregation, we applied optoDroplet technique Caenorhabditis elegans ( C. ), which allows spatiotemporal modulation phase separation assembly. Results We that optogenetically induced aggregates exhibited insolubility similar to observed These increased severity neurodegeneration, particularly GABAergic motor neurons, exacerbated sensorimotor dysfunction . Conclusions present an optogenetic model proteinopathy provides insight into neuropathological mechanisms aggregates. Our serves as promising tool for identifying therapeutic targets

Language: Английский

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Semi-synthesis of TDP-43 reveals the effects of phosphorylation in N-terminal domain on self-association

Communications Chemistry, Journal Year: 2025, Volume and Issue: 8(1)

Published: April 25, 2025

TDP-43, a nucleocytoplasmic shuttle protein consisting of 414 residues, forms self-association in the nucleus for physiological gene regulation, while aggregation into amyloid (consisting aberrant β-sheets) cytoplasm causes neurodegenerative diseases such as amyotrophic lateral sclerosis. Post-translational phosphorylation TDP-43 alters properties, which affects both function and amyloidogenic potential cytoplasm, thereby impacting upon disease progression. However, insight role per-residue remains limited due to difficulty obtaining site-specifically phosphorylated TDP-43. Here, we demonstrate semi-synthesis full-length that is uniformly at 48th serine residue (designated TDP1-414[pS48]). The synthetic scheme native chemical ligation followed by His-tag affinity chromatography efficiently gave TDP1-414(pS48) with high purity. Interestingly, unlike non-phosphorylated was found have weak property form aggregates were not typical fibrils. Furthermore, synthesis three-dimensional structure analysis N-terminal domain (NTD, corresponding TDP1-80) suggested phosphate ion Ser48 weakens inter-NTD interaction inducing electrostatic repulsion. It significantly advances understanding pathological mechanisms involved post-translational modifications associated diseases.

Language: Английский

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TDP-43 seeding activity in the olfactory mucosa of patients with amyotrophic lateral sclerosis

Molecular Neurodegeneration, Journal Year: 2025, Volume and Issue: 20(1)

Published: April 26, 2025

Abstract Background In recent years, the seed amplification assay (SAA) has enabled identification of pathological TDP-43 in cerebrospinal fluid (CSF) and olfactory mucosa (OM) patients with genetic forms frontotemporal dementia (FTD) amyotrophic lateral sclerosis (ALS). Here, we investigated seeding activity OM samples collected from sporadic ALS. Methods were (a) motor neuron diseases (MND), including spinal ALS ( n = 35), bulbar 18), primary 10), facial onset sensory neuronopathy 2); (b) MND, carriers C9orf72 exp 6), TARDBP 4), SQSTM1 3), + 1), OPTN GLE1 FUS 1) SOD1 4) mutations; (c) other neurodegenerative disorders (OND), Alzheimer’s disease Lewy bodies 8) multiple system atrophy 6); (d) control subjects 22). All subjected to SAA analysis for (TDP-43_SAA). Plasmatic levels neurofilament-light chain (NfL) also assessed a selected number patients. Results TDP-43_SAA was positive 29/65 9/21 6/17 OND 3/22 controls. Surprisingly, one presymptomatic individual tested positive. As expected, non-TDP-43-related MND negative. Interestingly, fluorescence values non-MND that consistently significantly lower than those obtained MND. Furthermore, among TDP-43-positive samples, lag phase observed longer Plasma higher compared controls decreased as progressed. Similarly, plasma NfL both positively correlated progression rate (ΔFS). No significant correlations detected between findings biological, clinical, or neuropsychological parameters considered. Conclusions The subset can trigger TDP-43, previously Thus, improve clinical characterization across different phenotypes enhance our understanding these diseases. Finally, could serve potential biomarker monitoring progression. However, further research is needed confirm expand findings.

Language: Английский

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Cryo-EM structures of functional and pathological amyloid ribonucleoprotein assemblies

Trends in Biochemical Sciences, Journal Year: 2023, Volume and Issue: 49(2), P. 119 - 133

Published: Nov. 3, 2023

Language: Английский

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Enhanced legumain activity links progranulin deficiency to TDP-43 pathology in frontotemporal lobar degeneration

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 16, 2024

Loss-of-function mutations in GRN are a major cause of frontotemporal lobar degeneration (FTLD) with TDP-43-positive inclusions. Progranulin (PGRN) loss leads to lysosomal dysfunction, microglial hyperactivation, and TDP-43 deposition, yet the underlying pathomechanism remains unknown. We demonstrate that PGRN slows maturation limits proteolytic activity protease legumain (LGMN). Accordingly, LGMN is strongly elevated Grn knockout (ko) mice, human induced pluripotent stem cell-derived ko microglia, FTLD- patients’ brain. Secreted internalized by neurons, where it mediates pathological processing TDP-43, which prevented selective inhibition. In contrast, AAV-mediated overexpression mouse brains promotes processing, aggregation phosphorylated increases plasma neurofilament light chain (NfL), marker for neuronal loss. Our findings identify as link between haploinsufficiency pathology suggest therapeutic target.

Language: Английский

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Single acetylation-mimetic mutation in TDP-43 Nuclear Localization Signal disrupts importin α1/β signaling

Journal of Molecular Biology, Journal Year: 2024, Volume and Issue: 436(20), P. 168751 - 168751

Published: Aug. 23, 2024

Language: Английский

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