bims-proned Biomed News
on Proteostasis in neurodegeneration
Issue of 2026–01–25
seventeen papers selected by
Verena Kohler, Umeå University
  1. Editorial: Cellular contributors and consequences of protein misfolding and aggregation.
  2. Heat shock protein 10 as a chaperone modulating α-synuclein amyloid fibril formation.
  3. Hidden faces of alpha-synuclein: Cryo-EM revelation of fibril polymorphs driven by disease, mutations, and PTMs.
  4. Heterotypic phase separation in aggregation: Driver or deterrent?
  5. Water Accelerates in the Hydration Shell of the N- and C-Terminal Domains of α-Synuclein in the Presence of NaCl.
  6. Concentration-dependent mutational scanning probes the cellular folding landscape of α-synuclein in yeast.
  7. ALS-related proteinopathies: From TDP-43 to mitochondrial proteinopathies.
  8. Small molecule JRMS modulating importin-β1 chaperone activity as a therapeutic strategy reducing TDP-43 pathology.
  9. Deletion of the Saccharomyces cerevisiae RACK1 homolog, ASC1, enhances autophagy which mitigates TDP-43 toxicity.
  10. Oligomers mediate the spatial transmission of Aβ peptide aggregation.
  11. Cytoplasmic TDP-43 leads to early behavioral impairments without neurodegeneration in a serotonergic neuron-specific C. elegans model.
  12. Glycerol 3-phosphate acyltransferase exacerbates α-synuclein-induced toxicity by increasing lipid peroxidation.
  13. Effects of different organic solvents on the structure of Aβ_{1-42} monomer.
  14. Mechanistic Insights Into Protein Aggregation Inhibition by Green-Synthesized Silver Nanoparticles: A Study on Human Lysozyme.
  15. Potential role of stress granules and myogranules in amyotrophic lateral sclerosis.
  16. Fluorescence from dual molecular rotors allows sensitive detection of widespread brain pathology in a mouse model of Alzheimer's disease.
  17. GFP-free live neuron quantitative imaging reveals compartmentalization and growth dynamics of polyQ aggregates.
  1. Front Mol Biosci. 2025 ;12 1759495
    Editorial: Cellular contributors and consequences of protein misfolding and aggregation.
    Anoop Arunagiri, Emily Sontag, Verena Kohler, Arunkumar Venkatesan.
      
    Keywords:  endoplasmic reticulum–mitochondria association; liquid–liquid phase separation; neurodegeneration; protein aggregation; proteostasis
    DOI:  https://doi.org/10.3389/fmolb.2025.1759495
  2. Protein Sci. 2026 Feb;35(2): e70452
    Heat shock protein 10 as a chaperone modulating α-synuclein amyloid fibril formation.
    Johan N K Larsson, Ranjeet Kumar, Fiamma Ayelen Buratti, Sofie Nyström, Pernilla Wittung-Stafshede, Per Hammarström.
      HSP10 is a well-known human co-chaperone that interacts with HSP60 to comprise the HSP60/10 chaperonin complex which upholds mitochondrial proteostasis. HSP10 also demonstrates independent roles in binding to misfolded proteins and interacts with several amyloidogenic client proteins. Using a variety of biophysical and biochemical methods, we studied the interactions of HSP10 with the amyloidogenic protein α-synuclein (α-syn) associated with Parkinson's disease. HSP10 efficiently inhibited fibril formation of wild type (WT) and disease-mutant A30P α-syn at sufficient concentrations of chaperone by both binding to α-syn monomers and by blocking secondary nucleation on fibril surfaces. However, under sub-stoichiometric conditions, below 1:5 (HSP10:α-syn), the chaperone sequestered multiple A30P α-syn monomers and thereby promoted nucleation of fibril formation with a magnitude comparable to the efficacy of seeding with preformed fibrils. The fibril formation acceleration effect of the HSP10 chaperone was client-specific as it was observed for A30P but not WT α-syn. Our results broaden the scope of HSP10 chaperone activity and can have implications for disease onset in synucleinopathies.
    Keywords:  alpha‐synuclein; amyloid fibril; atomic force microscopy; heat shock protein; molecular chaperone; small angle X‐ray scattering
    DOI:  https://doi.org/10.1002/pro.70452
  3. BBA Adv. 2026 ;9 100179
    Hidden faces of alpha-synuclein: Cryo-EM revelation of fibril polymorphs driven by disease, mutations, and PTMs.
    Mitra Pirhaghi, Fatemeh Mamashli, Bagher Davaeil, Mahya Mohammad-Zaheri, Zahra Mousavi-Jarrahi, Jörg Tatzelt, Ali Akbar Saboury.
      Alpha-synuclein (α-Syn) is a neuronal protein implicated in the pathogenesis of several neurodegenerative disorders collectively known as synucleinopathies, including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. This article provides a comprehensive overview of the structural characteristics of α-Syn, emphasizing its fibrillar aggregation and the resulting polymorphic fibril forms. Using advances in cryo-electron microscopy, a diverse range of α-Syn fibril polymorphs has been elucidated, both from in vitro preparations and patient-derived brain samples. We further explore the impact of mutation and post-translational modifications-such as truncation and phosphorylation -on α-Syn structure and the unique polymorphs they induce. The article underscores the biological and pathological relevance of α-Syn polymorphism, highlighting how different structural strains may underlie the structural and pathological heterogeneity observed in synucleinopathies. Understanding the mechanisms driving polymorph formation is critical for deciphering disease progression and developing targeted therapeutic strategies.
    Keywords:  Amyloid fibril; Cryo-EM; Fibril polymorphism; Parkinson's disease; α-Synuclein
    DOI:  https://doi.org/10.1016/j.bbadva.2025.100179
  4. Biophys Chem. 2026 Jan 12. pii: S0301-4622(26)00010-4. [Epub ahead of print]331 107577
    Heterotypic phase separation in aggregation: Driver or deterrent?
    Tina Jacob, Wolfgang Hoyer.
      Liquid-liquid phase separation (LLPS) of proteins implicated in neurodegenerative diseases has gained growing attention in recent years, due to its potential role in driving the transition from functional protein monomers to pathogenic aggregates. However, the mechanisms by which phase separation contributes to the loss of protein function and promotes aggregation remain poorly understood. Recent studies show that multiple proteins or other biomolecules can colocalize within the biomolecular condensates, creating a highly interactive microenvironment that can modulate aggregation. In this review we look into the heterotypic phase separation of tau and α-synuclein, the two key proteins responsible for critical neurodegenerative disorders. By compiling recent findings, this review highlights the modulatory role of heterotypic condensates in disease progression and aims to provide an alternative perspective on regulation of protein aggregation in neurodegeneration.
    Keywords:  Heterotypic condensates; Liquid–liquid phase separation (LLPS); Neurodegenerative diseases; Protein aggregation; Tau protein; α-Synuclein
    DOI:  https://doi.org/10.1016/j.bpc.2026.107577
  5. J Phys Chem B. 2026 Jan 21.
    Water Accelerates in the Hydration Shell of the N- and C-Terminal Domains of α-Synuclein in the Presence of NaCl.
    Stephen J Koehler, Valerie Vaissier Welborn.
      α-Synuclein (α-Syn) is an intrinsically disordered protein (IDP) whose aggregation into fibrils is implicated in Parkinson's disease (PD). While benign α-Syn aggregation frequently occurs, off-target aggregates are implicated in disease progression. Although most mechanisms of toxic α-Syn aggregate formation are unknown, high concentrations of salt ions have been shown to systematically result in faster aggregation. Previous work suggests that salt slows water in the hydration shell of α-Syn, promoting intermolecular interactions. Here, we use polarizable molecular dynamics (MD) to investigate the interactions between α-Syn and water in response to an increased NaCl concentration. While we also find that the water in the hydration shell of the nonamyloid-β component (NAC) domain slows down with increasing salt concentration, the water in the hydration shell of the N- and C-terminal domains accelerates. The segments of the N- and C-terminal domains that show faster water diffusion kinetics corroborate with truncation experiment results. Overall, our work suggests that α-Syn aggregation is related to partial salt-induced dehydration of the N- and C-terminal domains.
    DOI:  https://doi.org/10.1021/acs.jpcb.5c06647
  6. Protein Sci. 2026 Feb;35(2): e70456
    Concentration-dependent mutational scanning probes the cellular folding landscape of α-synuclein in yeast.
    Daeun Noh, Robert W Newberry.
      The misfolding and aggregation of α-synuclein is a central molecular event in the etiology of Parkinson's disease and related disorders. α-synuclein misfolding and pathology are both concentration-dependent, but it is not clear precisely how changes in concentration alter the folding landscape within cells. Whereas most conventional structural biology approaches offer limited resolution in living systems, deep mutational scanning can offer insight into the folding state of a protein in living cells, and we apply this method to probe concentration-dependent changes in the folding of α-synuclein in a popular yeast model of pathology. We discover that at a wide range of cellular concentrations, α-synuclein is highly biased toward formation of a membrane-bound amphiphilic helix that imparts toxicity. Population of this toxic state can be disrupted by mutations that reduce membrane affinity, which shift the folding equilibrium away from the membrane-bound state. Reduced-affinity variants exhibit distinct sensitivity to concentration relative to variants with WT-like affinity, likely because these variants are expressed at concentrations closer to their dissociation constant for membrane binding. These results show how mutational scanning can provide high-resolution insights into the folding landscape of proteins in living cells, which is likely to be of special utility for studying proteins that misfold and/or aggregate.
    Keywords:  concentration dependence; membrane binding; mutational scanning; protein misfolding; yeast; α‐synuclein
    DOI:  https://doi.org/10.1002/pro.70456
  7. Curr Opin Neurobiol. 2026 Jan 21. pii: S0959-4388(25)00194-1. [Epub ahead of print]97 103163
    ALS-related proteinopathies: From TDP-43 to mitochondrial proteinopathies.
    Emmanuelle C Genin, Véronique Paquis-Flucklinger.
      Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the progressive loss of motor neurons. ALS often overlaps clinically and pathologically with frontotemporal dementia (FTD), the second most common form of dementia. Like many neurodegenerative disorders, both ALS and FTD share a crucial pathological hallmark, the aggregation of misfolded proteins into insoluble inclusions in degenerating neurons. This process is referred to as proteinopathy. This review focuses on the proteinopathies associated with ALS, including aggregates of TDP-43, SOD1, FUS, and CHCHD10, which disrupt critical cellular processes such as RNA metabolism, mitochondrial function, and protein homeostasis. The review highlights to the identification of new types of mitochondrial and cytosolic aggregates linked to CHCHD10-related ALS. Although the precise pathological mechanisms remain to be fully elucidated, strategies aimed at restoring proteostasis and reducing protein aggregation may be promising therapeutic approaches for treating ALS, as they directly target fundamental pathogenic mechanisms.
    DOI:  https://doi.org/10.1016/j.conb.2025.103163
  8. Neurotherapeutics. 2026 Jan 17. pii: S1878-7479(26)00004-8. [Epub ahead of print] e00834
    Small molecule JRMS modulating importin-β1 chaperone activity as a therapeutic strategy reducing TDP-43 pathology.
    Marc Shenouda, Sandra Shenouda, Bryan Kartono, Shehab Eid, Cheryl Cheng, Janice Robertson.
      Neuronal cytoplasmic aggregation and nuclear depletion of the TAR DNA-binding protein 43 (TDP-43) is the most characteristic pathology of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), causing toxicity through cytoplasmic gain and nuclear loss of function mechanisms. In addition to its canonical role in nuclear cytoplasmic transport (NCT), the nuclear import receptor, importin-β1 (KPNB1) also acts as a molecular chaperone capable of preventing and reversing aberrant protein aggregation. Previous studies have demonstrated that increased expression of KPNB1 solubilizes TDP-43 aggregates and restores its nuclear localization. Here, we identify JRMS, a small molecule that enhances the chaperone activity of KPNB1 by increasing its cytoplasmic availability. JRMS treatment reduced cytoplasmic aggregation and promoted nuclear localization of full-length and pathological truncated TDP-43 variants across multiple experimental systems, including cell lines, primary neurons, iPSC-derived cortical neurons, organotypic brain slices and in vivo model. The effects of JRMS were KPNB1 dependent and occurred without inducing cytotoxicity or perturbing basal NCT. These findings identify JRMS as a promising therapeutic strategy for targeting TDP-43 pathology in ALS/FTD and other related TDP-43 proteinopathies.
    Keywords:  ALS; Chaperone; FTD; KPNB1; TDP-43; Therapeutic
    DOI:  https://doi.org/10.1016/j.neurot.2026.e00834
  9. Genetics. 2026 Jan 19. pii: iyag014. [Epub ahead of print]
    Deletion of the Saccharomyces cerevisiae RACK1 homolog, ASC1, enhances autophagy which mitigates TDP-43 toxicity.
    Sei-Kyoung Park, Sangeun Park, Susan W Liebman.
      Cytoplasmic aggregation of nuclear proteins such as TDP-43 (TAR DNA-binding protein 43) and FUS (fused in sarcoma) is associated with several neurodegenerative diseases. Studies in higher cells suggest that aggregates of TDP-43 and FUS sequester polysomes by binding RACK1 (receptor for activated C kinase 1), a ribosomal protein, thereby inhibiting global translation and contributing to toxicity. However, RACK1 is also a scaffold protein with a role in many other cellular processes including autophagy. Using yeast, we find that deletion of the RACK1 ortholog, ribosomal protein ASC1, reduces TDP-43 toxicity, but not FUS toxicity. TDP-43 foci remain liquid like in the absence of ASC1 but they become smaller. This is consistent with findings in mammalian cells. However, using double label fluorescent tags and co-immunoprecipitation we establish that ASC1 does not co-localize with TDP-43 foci, challenging the polysome sequestration hypothesis. Instead, ASC1 appears to influence toxicity through regulation of autophagy. We previously showed that TDP-43 expression inhibits autophagy and TOROID (TORC1 Organized in Inhibited Domains) formation and that genetic modifiers that rescue yeast from TDP-43 toxicity reverse these effects. Here we show that FUS does not inhibit autophagy. Deletion of ASC1 enhances a non-canonical form of autophagy that effectively counteracts TDP-43 induced autophagy inhibition despite reduced TOROID formation. Our findings highlight autophagy-not polysome sequestration-as a key mechanism underlying ASC1-mediated modulation of TDP-43 toxicity and suggest autophagy as a promising therapeutic target.
    Keywords:  ASC1/RACK1; FUS (fused in sarcoma); TDP-43 (TAR DNA-binding protein 43); TOROID; autophagy
    DOI:  https://doi.org/10.1093/genetics/iyag014
  10. Commun Chem. 2026 Jan 20. 9(1): 35
    Oligomers mediate the spatial transmission of Aβ peptide aggregation.
    Quentin Peter, Chris Taylor, Urszula Lapinska, Jiapeng Wei, Thomas C T Michaels, Paolo Arosio, Sara Linse, Tuomas P J Knowles.
      Alzheimer's disease (AD) is marked by the abnormal aggregation of amyloid-beta peptides within the central nervous system. The formation of amyloid fibrils from amyloid-beta peptides is a hallmark of AD Here, we demonstrate that the aggregation of amyloid-beta 42 spreads both spatially and temporally. By measuring the spatial propagation of amyloid-beta in macroscopic capillaries and performing Monte Carlo simulations, we show that this spreading occurs through a diffusion mechanism involving oligomers in solution. These species, catalytically produced through spontaneous secondary nucleation, significantly accelerate the propagation velocity of the reaction wavefront. Our findings suggest that, in addition to their potential role in toxicity, these oligomers in solution are key drivers of the spatial spreading of aggregation and can therefore be considered key targets for therapeutic intervention.
    DOI:  https://doi.org/10.1038/s42004-025-01837-z
  11. Sci Rep. 2026 Jan 23.
    Cytoplasmic TDP-43 leads to early behavioral impairments without neurodegeneration in a serotonergic neuron-specific C. elegans model.
    Ailín Lacour, Florencia Vassallu, Stefano Romussi, Diego Rayes, Lionel Muller Igaz.
      TDP-43 proteinopathies, such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), are marked by the pathological cytoplasmic accumulation of TAR DNA-binding protein 43 (TDP-43), leading to progressive neuronal dysfunction and degeneration. To investigate the early functional consequences of TDP-43 mislocalization, we generated Caenorhabditis elegans models expressing either wild-type human TDP-43 or a variant with a mutated nuclear localization signal (ΔNLS), specifically in serotonergic neurons. These neurons were chosen because in C. elegans they regulate well-characterized behaviors, providing a straightforward readout of neuronal function. We found that expression of either TDP-43 variant impaired serotonin-dependent behaviors-including pharyngeal pumping, egg-laying, and locomotion slowing upon food encounter-with the cytoplasmic ΔNLS form causing more severe deficits. These behavioral impairments are evident even while the serotonergic neurons remain apparently normal in structure, suggesting that neuronal dysfunction precedes overt neurodegeneration. Moreover, the serotonergic HSN neurons that control egg-laying were also partially responsive to the selective serotonin reuptake inhibitor fluoxetine, suggesting that neurotransmitter release remains functional to some extent. Altogether, our findings demonstrate that TDP-43 expression causes neuronal dysfunction leading to behavioral deficits, even in the absence of detectable structural pathology and that its mislocalization to the cytoplasm results in more severe behavioral impairments. This C. elegans model provides a genetically tractable system to dissect early mechanisms of TDP-43-mediated neuronal dysfunction and to identify therapeutic strategies targeting predegenerative stages of ALS/FTD.
    Keywords:  C. elegans; Neurodegeneration; Proteinopathies; Serotonergic neurons; TDP-43
    DOI:  https://doi.org/10.1038/s41598-026-36138-5
  12. Nat Commun. 2026 Jan 19.
    Glycerol 3-phosphate acyltransferase exacerbates α-synuclein-induced toxicity by increasing lipid peroxidation.
    Mengda Ren, Grace G Y Lim, Willcyn Tang, Kah-Leong Lim.
      Although multiple cellular pathways have been implicated in α-Synuclein (α-syn)-associated Parkinson's disease (PD), the role of lipid metabolism remains elusive. In this study, we identify Drosophila mino, which encodes the mitochondrial isoform of the lipid synthesis enzyme glycerol 3-phosphate acyltransferase (GPAT), as a potent modifier of α-syn. Silencing the expression of mino significantly suppresses α-syn-induced PD phenotypes in Drosophila, including dopaminergic neuronal loss and locomotion defects as well as circadian rhythm-related activities, whereas mino overexpression yields opposite effects. Mechanistically, we find that mino modulates the levels of mitochondrial reactive oxygen species and lipid peroxidation. Importantly, treatment of α-syn-expressing flies with FSG67, a GPAT inhibitor of glycerol 3-phosphate acyltransferase, reproduces the benefits of mino knockdown. FSG67 also inhibits α-syn aggregation and lipid peroxidation in mouse primary neurons treated with α-syn preformed fibrils. Our study elucidates an important factor contributing to α-syn toxicity and offers a therapeutic direction for PD.
    DOI:  https://doi.org/10.1038/s41467-026-68325-3
  13. Phys Rev E. 2025 Dec;112(6-1): 064409
    Effects of different organic solvents on the structure of Aβ_{1-42} monomer.
    Chen Chen, Huxuan Chen, Yousheng Yu, Rongri Tan.
      The aggregation of amyloid-β42 (Aβ42) peptide, a key pathological event in Alzheimer's disease, is strongly influenced by its solvent environment. While cosolvents are often used in experimental studies, their specific role in modulating the conformational stability and aggregation propensity of Aβ42 remains poorly understood. We perform molecular dynamics simulations to investigate the effects of three organic solvents-ethanol (EtOH), dimethyl sulfoxide (DMSO), and acetonitrile (ACN)-on the structural dynamics of Aβ42. Our results reveal a distinct dichotomy: EtOH and DMSO exert a stabilizing effect by promoting the α-helical content, reducing Coil formation, and extending the lifetime of intramolecular hydrogen bonds. In contrast, ACN destabilizes the native state and accelerates the formation of aggregation-prone β-sheet structures. We attribute these opposing effects to the solvents' differential disruption of the peptide's hydrophobic core and their specific interactions with the protein backbone. This work elucidates the microscopic mechanisms by which solvent environment directs Aβ42 conformational sampling, with implications for understanding aggregation pathways and designing modulating agents.
    DOI:  https://doi.org/10.1103/6c4s-bgyx
  14. IET Nanobiotechnol. 2026 ;2026 2694374
    Mechanistic Insights Into Protein Aggregation Inhibition by Green-Synthesized Silver Nanoparticles: A Study on Human Lysozyme.
    Md Tauqir Alam, Mohd Ahmar Rauf, Arman Khan, Rizwan Hussain.
      A characteristic of many neurodegenerative disorders, such as Parkinson's and Alzheimer's, is amyloidogenic protein aggregation, for which there are currently no proven cures. Aging, mutation, and physiological stress can cause proteins to deviate from their natural folding patterns, potentially leading to the formation of hazardous protein aggregates. Noble metal nanoparticles (NPs), due to their unique physicochemical properties, have emerged as promising tools in biomedicine, with applications ranging from tissue engineering to drug delivery and diagnostics. Although concerns regarding cytotoxicity exist, small-sized silver (Ag) NPs (AgNPs) have demonstrated potential in antiviral, anticancer, and antibacterial therapies. This study investigated the development of biocompatible AgNPs using a green synthesis approach and examined their chaperone-like activity against protein aggregation, emphasizing the role of meticulous in vitro design. Human lysozyme (HLZ) served as a model protein for aggregation inhibition assays. Biogenic AgNPs exhibited a concentration-dependent effect on HLZ aggregation, demonstrating an optimal inhibitory concentration, followed by a decrease in efficacy at higher concentrations. Furthermore, astrocytes treated with AgNPs displayed reduced protein aggregation, suggesting a chaperone-like behavior. The initial phase focused on the detailed characterization of AgNPs synthesized using orange juice extract. Subsequently, this study explored the mechanistic understanding of AgNP-mediated inhibition of protein aggregation under controlled conditions. A battery of biophysical techniques, including circular dichroism (CD), 8-anilino-1-naphthalene-sulfonic acid (ANS) fluorescence, thioflavin T (ThT) fluorescence, Congo red (CR) assay, and turbidity measurements, was employed to meticulously assess the inhibitory effect on HLZ aggregation in vitro.
    Keywords:  Congo red; human lysozyme; protein aggregation; silver nanoparticles; thioflavin T
    DOI:  https://doi.org/10.1049/nbt2/2694374
  15. Front Mol Neurosci. 2025 ;18 1686230
    Potential role of stress granules and myogranules in amyotrophic lateral sclerosis.
    Saddam Muhammad Ishaq, Aaron P Russell.
      Amyotrophic lateral sclerosis (ALS) is characterized by the progressive loss of upper and lower motor neurones, leading to muscle wasting, paralysis and respiratory failure. Pathological cytoplasmic aggregation of the RNA-binding protein transactive response DNA-binding protein 43 (TDP-43) protein occurs in neural tissues in ~97% of all ALS cases, and is also observed in skeletal muscle. Cytoplasmic aggregation of TDP-43 is believed to contribute to ALS pathogenesis; however, its precise mechanistic role/s continues to elude the field. This mini review explores the potential role and regulation of two TDP-43-associated RNA-protein assemblies, stress granules (SGs) and myogranules (MGs). We review the current understanding of SG and MG formation and their potential role in ALS-related neurodegeneration and muscle pathology. We also highlight limitations and strengths and suggest future directions for research.
    Keywords:  TDP-43; amyotrophic lateral sclerosis; brain; myogranule; skeletal muscle; spinal cord; stress granules
    DOI:  https://doi.org/10.3389/fnmol.2025.1686230
  16. Photochem Photobiol Sci. 2026 Jan 19.
    Fluorescence from dual molecular rotors allows sensitive detection of widespread brain pathology in a mouse model of Alzheimer's disease.
    Paula J Brandt, Olha Pototska, Peter K Stys.
      Amyloid fibrils formed by the misfolding and aggregation of proteins are a pathological hallmark of many neurodegenerative conditions including Alzheimer's disease (AD). Although recent studies have shown that pre-fibrillar species including low molecular-weight oligomers are more toxic in vitro than mature fibrils, and correlate better with cognitive decline in AD patients, techniques to study this subtle pathology remain limited. Here, we describe the use of the dye pair 9-(dicyanovinyl)julolidine (DCVJ) and crystal violet (CV), two fluorescent molecular rotors, to detect widespread pathology in the 5xFAD mouse model of AD via fluorescence spectroscopy. DCVJ and CV individually displayed a limited ability to detect spectral differences between WT and non-plaque areas of 5xFAD brain samples. However, when used in combination, the two probes discerned subtle but significant differences in a much higher proportion of tissue compared to either dye alone. These spectral differences were eliminated after treatment to disaggregate macromolecular protein assemblies, providing evidence that the dye pair was able to detect subtle pathology present in the parenchyma of the 5xFAD mouse brain. These findings demonstrate that the combined use of DCVJ and CV could be a valuable addition to the tools currently available to study the early stages of protein misfolding, which is essential for advancing therapeutics and diagnostic technologies in many neurodegenerative diseases.
    Keywords:  Alzheimer’s disease; Amyloid; Fluorescence; Machine learning; Protein misfolding; Spectral microscopy
    DOI:  https://doi.org/10.1007/s43630-025-00848-y
  17. Proc Natl Acad Sci U S A. 2026 Jan 27. 123(4): e2505321123
    GFP-free live neuron quantitative imaging reveals compartmentalization and growth dynamics of polyQ aggregates.
    Xiaotian Bi, Berea Suen, Li-En Lin, Kun Miao, Lu Wei.
      Huntington's Disease (HD), the most prevalent polyglutamine (polyQ) neurodegenerative disorder, features brain aggregates induced by mutant huntingtin (mHtt) proteins harboring expanded polyQ tracts. Despite extensive efforts, molecular mechanisms of polyQ aggregates remain elusive. Here, we establish quantitative stimulated Raman scattering imaging of polyQ aggregates (q-aggSRS) for noninvasive investigations in live neuronal cocultures using deuterated glutamine labeling. Q-aggSRS allows for specific visualization by targeting the distinct Raman peak from carbon-deuterium bonds, eliminating the need for bulky fluorescent protein tagging (e.g., EGFP). Coupled with analysis from aggregate-tailored expansion microscopy, newly designed two-color imaging, and pulse-chase visualization, we comprehensively quantified the mHtt and non-mHtt proteins within the same aggregates across varying sizes, cell types, mHtt constructs, and subcellular locations. Our findings demonstrate a two-phase aggregate model with a distinct core-shell spatial organization, reveal significant heterogeneity in nucleus/cytoplasm compartmentalization specific to neurons, and identify previously unrecognized loosely packed aggregates specifically in neuronal nuclei. These insights should advance our understanding of native polyQ aggregates, and our proposed interaction coefficients may offer quantitative parameters for developing effective HD therapies.
    Keywords:  live-neuronal imaging; protein aggregation; stimulated Raman scattering microscopy
    DOI:  https://doi.org/10.1073/pnas.2505321123
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