bims-proned 2025-07-06 papers

bims-proned

Biomed News

on Proteostasis in neurodegeneration

Issue of 2025–07–06
sixteen papers selected by
Verena Kohler, Umeå University

Heat shock proteins regulates Tau protein aggregation in Alzheimer's disease.
Alpha-synuclein aggregation in Parkinson's disease.
Proteostasis imbalance: Unraveling protein aggregation in neurodegenerative diseases and emerging therapeutic strategies.
Molecular dynamics simulation of the aggregation and folding mechanism of α-synuclein 47-56 in core peptide fragments induced by α-synuclein pentamer template.
Combining light-induced aggregation and biotin proximity labeling implicates endolysosomal proteins in early α-synuclein oligomerization.
Targeted degradation of α-synuclein by arginine-based PROTACs.
Tau protein aggregation: A therapeutic target for neurodegenerative diseases.
Small-diffusible aggregates, plaques, tangles, and dynamic equilibria: Untangling Alzheimer's disease.
Unravelling γD-crystallin aggregation pathway to understand cataract formation using fluorescence correlation spectroscopy.
The Neurotoxic Properties of α-synuclein Polymorphs.
Impact of Lysine Acetylation Mutations on the Structure of Full-Length Tau Fibrils.
Immunization targeting diseased proteins in synucleinopathy and tauopathy: insights from clinical trials.
Chaperone-Mediated Autophagy: A Critical Regulator of Neuroinflammation and Neurodegeneration.
The aggregation propensity of Tau and amyloid-β in Alzheimer's disease.
N-Homocysteinylation of lysine residues in α-Synuclein enhances aggregation propensity and cytotoxicity in SH-SY5Y cells.
Fisetin Attenuates Mutant SOD1 Aggregation in Amyotrophic Lateral Sclerosis via Nrf2-Mediated Autophagy Activation.

Adv Protein Chem Struct Biol. 2025 ;pii: S1876-1623(24)00084-1. [Epub ahead of print]146 161-178

Heat shock proteins regulates Tau protein aggregation in Alzheimer's disease.

Subashchandrabose Chinnathambi.

  Alzheimer's disease is one of the neurodegenerative diseases characterized by loss of integrity and function of the cell, leading to progressive neuronal loss and ultimately dementia. Tau is one of the most soluble protein mainly involved in assembly and disassembly of microtubules (MT) which helps in the anterograde and retrograde transport of cargos. However in AD conditions Tau is subjected to various insults such as hyperphosphorylation, glycation, glycosylation, truncation, acetylation, oxidation etc., which leads to the loss-of-function. Thus modified Tau loses its affinity for MT and aggregates to form toxic oligomers followed by matured neurofibrillary tangles (NFTs) which attains cross-β structure. The cellular machinery such as chaperones, ubiquitin-proteasome system (UPS) and lysosomes tries to resolve these aggregates and helps in its clearance. During AD pathology the cellular machinery fails to clear aggregates and leads to neuronal death. In this aspect several strategies have been employed to prevent Tau aggregation that includes inhibitors for kinases, activators for phosphatases, small molecule activators of heat shock protein response and small molecules that can prevent Tau aggregation and increases its association with chaperones.

Keywords:  Alzheimer’s disease; Chaperones; NFTs; Tau

DOI:  https://doi.org/10.1016/bs.apcsb.2024.08.003
Adv Protein Chem Struct Biol. 2025 ;pii: S1876-1623(24)00125-1. [Epub ahead of print]146 35-75

Alpha-synuclein aggregation in Parkinson's disease.

Igor José Siqueira da Silva, Manuele Figueiredo da Silva, Thiago Santos de Assis Dutra, Sheila Oliveira de Souza, João Xavier de Araújo-Júnior, Ana Catarina Rezende Leite, Érica Erlanny da Silva Rodrigues, Edeildo Ferreira da Silva-Júnior.

  Alpha-synuclein (α-Syn) aggregation is closely linked to the pathogenesis of Parkinson's disease, where misfolded monomers form toxic oligomers and amyloid fibrils, which accumulate as Lewy bodies. Several factors, such as genetic mutations, interactions with lipids and proteins such as p62 and ubiquitin, as well as, environmental conditions, e. g. the presence of toxic metals that lead to oxidative stress. Advances in understanding the molecular mechanisms of Parkinson's disease have driven the search for novel therapies, including strategies to inhibit α-Syn aggregation and reduce its cytotoxicity consequently. Natural compounds, such as Skullcapflavone II, and synthetic ones, such 4-triazole phenylamides and phenethylamides, have demonstrated to reduce α-Syn fibrillation and aggregation. This chapter discusses the most recent therapeutic strategies in the treatment of Parkinson's disease concerning the implications of α-Syn.

Keywords:  Aggregation promoter; Alpha-synuclein; Natural compounds; Synthetic compounds

DOI:  https://doi.org/10.1016/bs.apcsb.2024.11.002
Adv Protein Chem Struct Biol. 2025 ;pii: S1876-1623(24)00131-7. [Epub ahead of print]146 1-34

Proteostasis imbalance: Unraveling protein aggregation in neurodegenerative diseases and emerging therapeutic strategies.

Chandrabose Selvaraj, Periyasamy Vijayalakshmi, Dipali Desai, Jayakumar Manoharan.

  Neurodegenerative diseases such as Alzheimer's, Parkinson's, Huntington's, and ALS are defined by the accumulation of misfolded and aggregated proteins, which impair cellular function and result in progressive neuronal death. This chapter examines the critical function of proteostasis-cellular protein homeostasis-in sustaining neuronal health and its disruption as a key factor in disease progression. Proteostasis is upheld by a complex array of mechanisms, which encompass molecular chaperones, the ubiquitin-proteasome system, autophagy-lysosomal pathways, and mitochondrial quality control. Impairment of these systems leads to protein misfolding and aggregation, resulting in toxic cellular environments that promote neurodegeneration. Novel therapeutic approaches focus on restoring proteostasis through the enhancement of cellular protein folding, degradation, and clearance mechanisms. This encompasses small molecule chaperones, gene therapy, RNA-based treatments, immunotherapy, autophagy inducers, and stem cell-based approaches, each addressing distinct components of the proteostasis network to mitigate or prevent disease progression. While these therapies show potential, challenges persist, such as possible side effects, selective targeting, and the efficacy of blood-brain barrier penetration. Personalized medicine and combination therapies customized to specific disease profiles are increasingly recognized for their potential to improve efficacy and safety. This chapter consolidates recent developments in therapies aimed at proteostasis, addresses the challenges encountered in clinical applications, and outlines potential future directions for transformative treatments. Ongoing research indicates that proteostasis modulation may significantly alter the course of neurodegenerative disease treatment, potentially enhancing patient outcomes and quality of life.

Keywords:  Alzheimer’s and Parkinson’s therapies; Autophagy induction; Gene therapy; Molecular chaperones; Neurodegenerative diseases; Protein aggregation; Proteostasis

DOI:  https://doi.org/10.1016/bs.apcsb.2024.11.008
J Biomol Struct Dyn. 2025 Jul 03. 1-13

Molecular dynamics simulation of the aggregation and folding mechanism of α-synuclein 47-56 in core peptide fragments induced by α-synuclein pentamer template.

Ruijuan Liu, Xuewei Liu.

  The misfolding of intrinsically disordered α-synuclein protein, which can form β-sheet-rich fibrillar amyloid structures, is closely associated with Parkinson's disease (PD). The peptide α-synuclein 47-56 has been identified as the toxic core of α-synuclein and plays a pivotal role in the aggregation and misfolding processes of this protein. Investigating the template induction behavior of this peptide is crucial for elucidating the molecular mechanisms underlying α-synuclein misfolding and aggregation. To explore the molecular mechanism of the peptide α-synuclein 47-56, guided by the α-synuclein pentamer template, we conducted a 400 ns molecular dynamics simulation. In this simulation, the peptide α-synuclein 47-56 was positioned on both sides of the α-synuclein pentamers. Our results demonstrate distinct elongation characteristics of the peptide α-synuclein 47-56 on the two sides of the pentamer. The β-sheet structure readily formed on the left side of the α-synuclein pentamer, facilitating template induction. In contrast, the formation of β-sheet secondary structures was hindered on the right side of the α-synuclein pentamer. Furthermore, our analysis reveals that hydrogen bonding, electrostatic interactions, and van der Waals forces between the α-synuclein pentamer and monomer are crucial for β-sheet extension. Notably, we identified the α-synuclein 49-53 region as a key peptide segment in this process.

Keywords:  Molecular dynamics simulation; aggregation; mechanism; seeding; α-synuclein

DOI:  https://doi.org/10.1080/07391102.2025.2528927
iScience. 2025 Jul 18. 28(7): 112823

Combining light-induced aggregation and biotin proximity labeling implicates endolysosomal proteins in early α-synuclein oligomerization.

Maxime Teixeira, Razan Sheta, Dylan Musiol, Vetso Ranjakasoa, Jérémy Loehr, Jean-Philippe Lambert, Abid Oueslati.

  Alpha-synuclein (α-syn) aggregation is a defining feature of Parkinson's disease (PD) and related synucleinopathies. Despite significant research efforts focused on understanding α-syn aggregation mechanisms, the early stages of this process remain elusive, largely due to limitations in experimental tools that lack the temporal resolution to capture these dynamic events. Here, we introduce UltraID-LIPA, an innovative platform that combines the light-inducible protein aggregation (LIPA) system with the UltraID proximity-dependent biotinylation assay to identify α-syn-interacting proteins and uncover key mechanisms driving its oligomerization. UltraID-LIPA successfully identified 38 α-syn-interacting proteins, including both established and previously unreported candidates, highlighting the accuracy and robustness of the approach. Notably, a strong interaction with endolysosomal and membrane-associated proteins was observed, supporting the hypothesis that interactions with membrane-bound organelles are pivotal in the early stages of α-syn aggregation. This powerful platform provides new insights into dynamic protein aggregation events, enhancing our understanding of synucleinopathies and other proteinopathies.

Keywords:  Biochemistry; Biological sciences; Molecular neuroscience; Natural sciences; Neuroscience

DOI:  https://doi.org/10.1016/j.isci.2025.112823
J Biol Chem. 2025 Jul 02. pii: S0021-9258(25)02299-9. [Epub ahead of print] 110449

Targeted degradation of α-synuclein by arginine-based PROTACs.

Linjing Shen, Jianchao Zhang, Zhaoran Wang, Yaxuan Liu, Shengjin Cui, Hai Rao.

  Parkinson's disease (PD), the second most prevalent neurodegenerative disorder, is associated with α-synuclein (α-syn) overexpression or mutation, leading to harmful aggregates and neuronal apoptosis. Effective drugs that inhibit or reduce α-syn accumulation remain challenging. Targeted protein degradation (TPD) technology offers a novel solution by utilizing the ubiquitin-proteasome pathway to target specific proteins for destruction. Here, we have developed Proteolysis Targeting Chimera (PROTAC) to target α-syn for degradation. Specifically, our PROTACs employ the amino acid arginine (Arg) as the E3 ligase ligand, and a benzothiazole-aniline variant as the warhead for α-syn. The efficacy of these PROTACs in degrading α-syn and its aggregates was tested in mammalian cells and Caenorhabditis elegans (C. elegans) models. Arg-PEG1-Tα-syn shows the highest degradation effect in mammalian cells for both wild-type α-syn and the α-syn (A53T) mutant. UBR1 is the ubiquitin E3 ligase responsible for PROTAC-mediated degradation. Furthermore, Arg-PEG1-Tα-syn significantly reduces α-syn aggregates and associated toxicities in both mammalian cells and C. elegans. These findings highlight the potential of a single amino acid-based PROTAC targeting α-syn for degradation, representing a possible therapeutic approach for PD and other synucleinopathies.

Keywords:  AATac; N-end rule; PROTAC; Parkinson's disease; amino acid; arginine; α-synuclein

DOI:  https://doi.org/10.1016/j.jbc.2025.110449
Adv Protein Chem Struct Biol. 2025 ;pii: S1876-1623(24)00135-4. [Epub ahead of print]146 77-136

Tau protein aggregation: A therapeutic target for neurodegenerative diseases.

Aryan Duggal, Drishti Mahindru, Kirti Baghel, Sanjana Mehrotra, Vijay Kumar Prajapati.

  Tau protein, a critical element for neuronal structure, becomes pathogenic in numerous neurodegenerative diseases, particularly Alzheimer's disease and other tauopathies. Under normal conditions, tau stabilizes microtubules and supports essential cellular transport systems. However, in disease states, tau undergoes abnormal modifications-most notably hyperphosphorylation-causing it to detach from microtubules and aggregate into neurofibrillary tangles. These aggregates disrupt neuronal function, leading to progressive cognitive and motor deficits. This chapter provides a comprehensive overview of tau's structural properties, normal cellular roles, and the cascade of pathological changes that transform it into a neurotoxic agent. We examine current therapeutic strategies targeting tau, including efforts to inhibit its phosphorylation, prevent aggregation, and enhance its clearance from cells. Approaches such as kinase inhibitors, immunotherapies, and gene-based therapies are discussed in the context of their potential to halt or slow disease progression. Additionally, recent advancements in diagnostic tools-such as tau-specific PET imaging and blood biomarkers-are highlighted as transformative for early detection of the disease .

Keywords:  Microtubule; Neurogenerative diseases; Protein aggregation; Tauopathies

DOI:  https://doi.org/10.1016/bs.apcsb.2024.11.012
Alzheimers Dement. 2025 Jul;21(7): e70462

Small-diffusible aggregates, plaques, tangles, and dynamic equilibria: Untangling Alzheimer's disease.

Emre Fertan, Georg Meisl, David Klenerman.

   INTRODUCTION: Beta-amyloid plaques and hyperphosphorylated tau tangles are the neuropathological hallmarks of Alzheimer's disease; however, their relevance in the pathophysiology is not fully understood. It has been suggested that these larger and insoluble aggregates may not be the most toxic forms of beta-amyloid and tau in Alzheimer's disease, and the disease progression may actually be promoted by the small-diffusible aggregates.
METHODS AND RESULTS: We combine the recent findings from our group and other key research to put forward the hypotheses that the formation of the small-diffusible aggregates of beta-amyloid and tau and their larger insoluble counterparts is not a linear process.
DISCUSSION: While the small-diffusible aggregate formation of beta-amyloid and tau is a passive process, regulated by thermodynamic equilibria, the formation of large-insoluble aggregates is an active process, regulated by microglia and neurons, which to an extent is a protective mechanism against the toxicity of the smaller aggregates.
HIGHLIGHTS: Plaques and tangles may be made by active processes in Alzheimer's disease. The small-soluble aggregates may be the more toxic species in Alzheimer's disease. Pathology may be caused by the imbalance of production and clearance of aggregates. Plaques and tangle formation may be attempts to restore the homeostatic equilibrium.

Keywords:  Alzheimer's disease; beta‐amyloid; caspase; microglia; oligomer; plaque; post‐translational modification; small‐diffusible aggregate; tangle; tau; truncation

DOI:  https://doi.org/10.1002/alz.70462
Mol Vis. 2025 ;31 190-202

Unravelling γD-crystallin aggregation pathway to understand cataract formation using fluorescence correlation spectroscopy.

Mangesh Bawankar, Bhaswati Sengupta, Sujata Malik, Pratik Sen, Ashwani K Thakur.

Purpose: To characterize the aggregation behavior of the γD-crystallin protein in an acidic environment with a focus on the formation of intermediate species. The research employs fluorescence correlation spectroscopy to unravel the intricate molecular events leading to aggregation, contributing to a comprehensive understanding of cataract formation.
Methods: The kinetics of γD-crystallin protein aggregation were studied with a reversed-phase high-performance liquid chromatography sedimentation assay, a ThT binding assay, and light scattering. We used fluorescence correlation spectroscopy (FCS) to recognize intermediate aggregate species and characterized them with Fourier transform infrared spectroscopy (FTIR). Further, the morphologic characterization of aggregates was done by transmission electron microscopy (TEM), and their hydrophobic characteristics were analyzed using the 8-anilino-1-naphthalenesulfonic acid binding assay.
Results: A negligible lag phase was observed in the aggregation kinetic experiments of the γD-crystallin protein. Pentamer, 25-mer, and higher oligomer intermediates were formed on the aggregation pathway. Conformation studies by FCS and FTIR have shown that oligomers are rich in cross-β sheet and random coil structure; however, they constitute more α-helix and less cross-β sheet structure than fibrils. TEM analysis revealed the approximate size of oligomers (diameter ~10 nm), protofibrils (~15 nm), and fibrils (~15 to ~35 nm).
Conclusions: In this study, we reported the presence of various intermediate aggregate species formed on the aggregation pathway of γD-crystallin protein at low pH. This will open new areas of research in understanding the detailed aggregation mechanism and aggregation hotspot within unfolded γD-crystallin monomers. The insights gained will also pave the way for future research in the realm of amyloid formation in cataract.
Exp Neurobiol. 2025 Jun 30. 34(3): 87-94

The Neurotoxic Properties of α-synuclein Polymorphs.

Katherine Chang, Zulfeqhar Syed, Valentina Baena, Mark R Cookson, Changyoun Kim.

  Progressive neurodegeneration is a common pathological feature of synucleinopathies, which include dementia with Lewy bodies (DLB), Parkinson's disease (PD), and multiple system atrophy (MSA). Among mechanisms known to induce neurodegeneration, the presence of aggregated forms of α-synuclein (α-syn) has been extensively considered as a causal factor for cell death. These aggregates exist in multiple different physical forms, which might yield different disease phenotypes and explain the heterogeneity among these diseases. Here, we investigated the neurotoxic properties of structurally distinct and exogenous α-syn polymorphs. Most of the polymorphs at the concentrations we studied are neurotoxic, but dopamine stabilized α-syn oligomer induced greater levels of neurotoxicity at lower concentrations compared to other polymorphs. In addition, polymorphs commonly induced apoptotic neuronal death through autophagic impairment. Our results suggest that neurons have different sensitivities to different α-syn aggregates, which should be a consideration when developing disease markers and therapeutics.

Keywords:  Autophagy; Neurotoxicity; Polymorphs; Synucleinopathy; α-Synuclein

DOI:  https://doi.org/10.5607/en25016
ACS Chem Neurosci. 2025 Jul 02.

Impact of Lysine Acetylation Mutations on the Structure of Full-Length Tau Fibrils.

Aurelio J Dregni, Mei Hong.

  The tau protein aggregates into amyloid fibrils in Alzheimer's disease and other neurodegenerative diseases. In these tauopathies, tau is decorated with posttranslational modifications, including phosphorylation and acetylation, suggesting that these modifications may cause tau to aggregate into specific pathological structures. Here, we investigate how pseudoacetylation of three lysine residues, K311Q, K321Q, and K369Q, affects the fibrilization and fibril structure of full-length four-repeat tau. These acetyl mimics are in addition to four phospho-mimetic glutamate mutations at the PHF1 epitope (4E tau). The joint mutant 4E3Q tau formed well-ordered amyloid fibrils without anionic cofactors. The 4E3Q tau fibrils lack twists, preventing structure determination by cryoelectron microscopy and necessitating characterization by solid-state NMR. 13C and 15N chemical shifts indicate that pseudoacetylation caused the protein to adopt a distinct fold from the parent 4E tau fibrils: the rigid core contains β-strands between R2 and R4 repeats and near the end of the C-terminal domain. Importantly, the C-terminal half of the R3 repeat containing the K321Q mutation is disordered, in qualitative contrast with 4E tau. Chemical shifts indicate that these structural changes likely result from the disruption of salt bridges between lysine and aspartate residues. 4E3Q tau contains an immobilized R2, which differs from that of AD tau. These results provide insights into the impact of acetylation on tau fibrilization and fibril structure and suggest that acetylation of these three lysine residues in AD may occur after the formation of the paired-helical filament structure.

Keywords:  Alzheimer’s disease; cryoEM; posttranslational modification; protein aggregation; salt bridge; solid-state NMR

DOI:  https://doi.org/10.1021/acschemneuro.5c00149
Transl Neurodegener. 2025 Jul 01. 14(1): 33

Immunization targeting diseased proteins in synucleinopathy and tauopathy: insights from clinical trials.

Xiaoni Zhan, Gehua Wen, Xu Wu, Jia-Yi Li.

  Synucleinopathies and tauopathies are neurodegenerative disorders characterized by the pathological accumulation of α-synuclein (α-syn) and tau proteins, respectively. These disorders are traditionally managed with symptomatic treatments without addressing the underlying pathologies. Recent advancements in passive immunotherapies, notably the FDA approval of the amyloid-beta (Aβ)-targeting antibody lecanemab, have sparked new hope in directly targeting pathological proteins. However, unlike the extracellular Aβ pathology, immunotherapies aimed at α-syn and tau, which predominantly form intracellular inclusions, face substantial challenges. To date, the therapeutic efficacy of five α-syn and 14 tau antibodies has been assessed in patients with synucleinopathies and tauopathies. These immunizations have demonstrated promising preclinical outcomes in alleviating pathological and behavioral deficits, but have not yielded significant clinical improvements in symptoms or measurable biomarkers. Therefore, a clear understanding of potential causes for the discrepancies between preclinical successes and clinical outcomes is critical for the successful translation of immunotherapy in the future. In this review, we examine existing passive immunotherapeutic strategies targeting α-syn and tau, specifically in patients with Alzheimer's disease and Parkinson's disease. Lessons learned from initial trial failures are also discussed, including refinement of animal models, inclusion and stratification of participants, improvement of clinical evaluations, and development of biomarkers. Given the overlapping pathologies and clinical manifestations of synucleinopathies and tauopathies, we further explore the potential of combined therapies targeting co-pathologies, offering novel insights for future therapeutic development against these neurodegenerative disorders.

Keywords:  Co-pathology; Passive immunotherapy; Synucleinopathy; Tau; Tauopathy; α‑Synuclein

DOI:  https://doi.org/10.1186/s40035-025-00490-9
Adv Biol (Weinh). 2025 Jul 02. e00191

Chaperone-Mediated Autophagy: A Critical Regulator of Neuroinflammation and Neurodegeneration.

Ying-Ying Han, Xin-Yue Huang, Ying Su, Jing-Jing Ma, Jin Wu.

  Neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD), are characterized by hallmark pathological features such as the accumulation of misfolded proteins and neuroinflammation. Chaperone-mediated autophagy (CMA), a selective lysosomal pathway, facilitates the degradation of proteins containing KFERQ-like motifs via the receptor lysosome-associated membrane protein type 2A (LAMP2A). In the recent review, the pivotal role of CMA in regulating proteostasis and modulating inflammatory responses is highlighted. This commentary explores the multifaceted roles of CMA in neurodegenerative disease progression, emphasizing its involvement in age-related decline, feedback loops between CMA dysregulation and neurodegeneration, and potential as a therapeutic target. Emerging CMA activators and the challenges of modulating CMA for clinical use are also discussed.

Keywords:  aging; chaperone‐mediated autophagy; neurodegenerative diseases; neuroinflammation; therapeutic potential

DOI:  https://doi.org/10.1002/adbi.202500191
Adv Protein Chem Struct Biol. 2025 ;pii: S1876-1623(24)00105-6. [Epub ahead of print]146 179-199

The aggregation propensity of Tau and amyloid-β in Alzheimer's disease.

Subashchandrabose Chinnathambi, Murugappan Kumarappan, Madhura Chandrashekar, Sneha Malik.

  Alzheimer disease is a multifactorial disease and can be due to many factors which includes gene mutation, cellular stress, toxicity, neuroinflammation, biomolecules dyshomeostasis, organelle stress and dysfunction, age, gender, ethnicity and other medical conditions are correlate with AD. Alzheimer disease, a progressive neurodegenerative disease characterized by presence of amyloid plaques and neurofibrillary tangles. These protein aggregates cause neurodegeneration, leading to cognition decline, finally memory loss. During disease progression, cross talk between the factors one with each other making disease condition worsen. Cross-talk leads to several cellular changes mainly functional change in both neural and neuro-glial cells. The neuronal changes are mitochondrial dysfunction, endoplasmic reticulum stress and synaptic loss. The neuro-glial changes include demyelination, neuroinflammation and phagocytosis. This change releases few proteins in CSF and blood which can be used as biomarker.

Keywords:  Alzheimer’s disease; Amyloid plaques; Biomarker; Neurofibrillary tangles; Risk factor; Tau

DOI:  https://doi.org/10.1016/bs.apcsb.2024.10.004
Sci Rep. 2025 Jul 02. 15(1): 23028

N-Homocysteinylation of lysine residues in α-Synuclein enhances aggregation propensity and cytotoxicity in SH-SY5Y cells.

Mohsen Masoumian Hosseini, Manhal Abdulameer, Roya Altafi, Dina Morshedi, Ali Es-Haghi, Seyyed Hossein Khatami, Farzaneh Salmani, Hessam Sepasi Tehrani, Sajad Ehtiati, Marziyeh Goudarzi, Bahram Gholamali Yaghmaei, Saeed Karima.

  In the current study, the effects of N-homocysteine thiolactone (HcyT) modification on expressed α-synuclein and the SH-SY5Y cell line were investigated. Various fluorometric, cell viability, and flow cytometry assays were employed to analyze the extent and impacts of modification under reducing/non-reducing conditions and different incubation durations. Our results confirmed that under non-reducing conditions, protofibrils exhibited a heightened propensity for aggregation with longer incubation periods. The increased tendency for aggregates following modification could be attributed to intermolecular forces, notably the establishment of π-stacking and hydrophobic interactions, consequent to the disruption of electrostatic charges due to lysine residues. Furthermore, our findings corroborated that N-homocysteinylation of α-synuclein by HcyT induces apoptosis in SH-SY5Y cells, suggesting that such a modification may indeed contribute to the onset and progression of Parkinson's disease (PD) in patients. Deciphering the underlying mechanisms using enhanced resolution techniques at the molecular level can pave the way to unraveling the pathogenesis associated with PD, as well as proposing effective strategies and countermeasures to mitigate the onset and progression of the disease. In light of the discoveries reported herein, N-homocysteinylation can be considered a risk factor and a potential biomarker in structural diseases, such as neurodegenerative disorders. Additionally, we propose that inhibiting N-homocysteinylation may impede protein aggregates and prevent the progression of neurodegeneration associated with these aggregates.

Keywords:   N-homocysteinylation; Apoptosis; Homocysteine Thiolactone (HcyT); Parkinson’s disease; SH-SY5 cell line

DOI:  https://doi.org/10.1038/s41598-025-08186-w
J Mol Neurosci. 2025 Jun 28. 75(3): 84

Fisetin Attenuates Mutant SOD1 Aggregation in Amyotrophic Lateral Sclerosis via Nrf2-Mediated Autophagy Activation.

Tianhang Wang, Ying Wang, Yueqing Yang, Shuyu Wang, Xudong Wang, Honglin Feng.

  Dysregulated autophagy and copper/zinc superoxide dismutase (SOD1) protein aggregation play a crucial role in amyotrophic lateral sclerosis (ALS). Here, we used stably transfected NSC34 motor neuron-like cells: (1) SOD1G93A mutants (G93A), (2) wild-type SOD1 (WT) controls, and (3) empty vector (EV) controls to observe the effects of fisetin. Pharmacological autophagy inhibition (Bafilomycin A1, 40 nM) and nuclear factor erythroid 2-related factor 2 (Nrf2) gene silencing (siRNA transfection) were employed to dissect molecular pathways. Protein aggregation dynamics and autophagy markers (LC3, p62/SQSTM1) were quantified through immunofluorescence and immunoblotting. SOD1G93A models exhibited impaired autophagic flux evidenced by elevated LC3-II and p62 levels, correlating with increased detergent-insoluble SOD1 aggregates. Fisetin treatment (1-10 μ M) dose-dependently reduced both soluble and aggregated SOD1G93A protein, concomitantly with restored autophagic flux. Mechanistically, fisetin promoted nuclear translocation while decreasing cytoplasmic Nrf2. After administration of an autophagy inhibitor and interference with Nrf2, the regulation of fisetin on p62 and mutant hSOD1 protein was inhibited. Our findings demonstrate that fisetin ameliorates mutant SOD1 proteotoxicity through coordinated activation of Nrf2-mediated autophagy pathways, suggesting therapeutic potential for SOD1-associated ALS pathologies.

Keywords:  Amyotrophic lateral sclerosis; Antioxidant; Autophagy; Copper/zinc superoxide dismutase; Fisetin; Neurodegenerative disease

DOI:  https://doi.org/10.1007/s12031-025-02376-x