bims-proned 2025-06-08 papers

bims-proned

Biomed News

on Proteostasis in neurodegeneration

Issue of 2025–06–08
sixteen papers selected by
Verena Kohler, Umeå University

Regulation of polyamine interconversion enzymes affects α-Synuclein levels and toxicity in a Drosophila model of Parkinson's Disease.
RNA-binding proteins in ALS and FTD: from pathogenic mechanisms to therapeutic insights.
Multiscale simulations elucidate the mechanism of polyglutamine aggregation and the role of flanking domains in fibril polymorphism.
Clearance of protein aggregates during cell division.
Engineered sequestrins inhibit aggregation of pathogenic alpha-synuclein mutants.
The Role of Kinases in Neurodegenerative Diseases: From Pathogenesis to Treatment.
The a-type domain of protein disulfide isomerase suppresses amyloid-β aggregation and cytotoxicity.
Lowering pathological α-synuclein.
Genetic Code Expansion and Enzymatic Modifications as Accessible Methods for Studying Site-Specific Post-Translational Modifications of Alpha-Synuclein and Tau.
Synaptic proteins that aggregate and degrade slower with aging accumulate in microglia.
Inhibitory effect of Fisetin against the aggregation process of SOD1 E100K mutant: computer-based drug design as a potential therapeutic for ALS disease.
TDP-43 dysregulation of polyadenylation site selection is a defining feature of RNA misprocessing in amyotrophic lateral sclerosis and frontotemporal dementia.
Effect of pyrimethanil on aβ42 aggregation mechanisms revealed at single entity level and molecular dynamic simulations.
Generation of iPSC lines with tagged α-synuclein for visualization of endogenous protein in human cellular models of neurodegenerative disorders.
The many connections of UFMylation with Alzheimer's disease: a comprehensive review.
Shedding light on the α-synuclein fibril fuzzy coat.

Res Sq. 2025 May 15. pii: rs.3.rs-6648986. [Epub ahead of print]

Regulation of polyamine interconversion enzymes affects α-Synuclein levels and toxicity in a Drosophila model of Parkinson's Disease.

Bedri Ranxhi, Zoya R Bangash, Zachary M Chbihi, Zaina Qadri, Nazin N Islam, Sokol V Todi, Peter A LeWitt, Wei-Ling Tsou.

Parkinson's Disease (PD) is a prevalent neurodegenerative disorder characterized by the accumulation and aggregation of α-synuclein as a defining pathological hallmark. Misfolding and aggregation of α-synuclein disrupt cellular homeostasis, hinder mitochondrial function, and activate neuroinflammatory responses, ultimately resulting in neuronal death. Recent biomarker studies have reported a significant increase in the serum concentrations of three L-ornithine-derived polyamines, correlating with PD progression and its clinical subtypes. However, the precise role of polyamine pathways in PD pathology remains poorly understood. In this study, we explored the impact of modifying polyamine-interconversion enzymes (PAIE) on the α-synucleinopathy phenotype in a Drosophila melanogaster model of Parkinson's Disease (PD). We assessed key degenerative features, including lifespan, locomotor function, tissue integrity, and α-synuclein accumulation. We found that PAIEs play a critical role in modulating α-synuclein toxicity in the PD model. Knockdown of ornithine decarboxylase 1 (ODC1), spermidine synthase (SRM), and spermine oxidase (SMOX) mitigates α-synuclein toxicity, whereas suppression of spermidine/spermine N1-acetyltransferase 1 (SAT1) and spermine synthase (SMS) exacerbates it. Furthermore, the overexpression of SAT1 or SMOX significantly lowers α-synuclein toxicity, emphasizing their potential involvement in PD. These results highlight the importance of polyamine pathways in PD, where PAIEs are essential in managing α-synuclein toxicity, providing a new perspective on targeting PD's fundamental pathology.

DOI: https://doi.org/10.21203/rs.3.rs-6648986/v1
Mol Neurodegener. 2025 Jun 04. 20(1): 64

RNA-binding proteins in ALS and FTD: from pathogenic mechanisms to therapeutic insights.

Jens Rummens, Sandrine Da Cruz.

  Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are devastating neurodegenerative disorders with overlapping clinical, genetic and pathological features. A large body of evidence highlights the critical role of RNA-binding proteins (RBPs) - in particular TAR DNA-binding protein 43 (TDP-43) and Fused in sarcoma (FUS) - in the pathogenesis of these diseases. These RBPs normally regulate various key aspects of RNA metabolism in the nervous system (by assembling into transient biomolecular condensates), but undergo cytoplasmic mislocalization and pathological aggregation in ALS and FTD. Furthermore, emerging evidence suggests that RBP-containing aggregates may propagate through the nervous system in a prion-like manner, driving the progression of these neurodegenerative diseases. In this review, we summarize the genetic and neuropathological findings that establish RBP dysfunction as a central theme in ALS and FTD, and discuss the role of disease-associated RBPs in health and disease. Furthermore, we review emerging evidence regarding the prion-like properties of RBP pathology, and explore the downstream mechanisms that drive neurodegeneration. By unraveling the complex role of RBPs in ALS and FTD, we ultimately aim to provide insights into potential avenues for therapeutic intervention in these incurable disorders.

Keywords:  Amyotrophic lateral sclerosis (ALS); FTLD; FUS; Frontotemporal dementia (FTD); Liquid–liquid phase separation (LLPS); Prion-like seeding; Protein aggregation; RNA-binding proteins (RBP); TDP-43

DOI:  https://doi.org/10.1186/s13024-025-00851-y
bioRxiv. 2025 May 23. pii: 2025.05.19.654960. [Epub ahead of print]

Multiscale simulations elucidate the mechanism of polyglutamine aggregation and the role of flanking domains in fibril polymorphism.

Avijeet Kulshrestha, Tien Minh Phan, Azamat Rizuan, Priyesh Mohanty, Jeetain Mittal.

Protein aggregation, which is implicated in aging and neurodegenerative diseases, typically involves a transition from soluble monomers and oligomers to insoluble fibrils. Polyglutamine (polyQ) tracts in proteins can form amyloid fibrils, which are linked to polyQ diseases, including Huntington's disease (HD), where the length of the polyQ tract inversely correlates with the age of onset. Despite significant research on the mechanisms of Httex1 aggregation, atomistic information regarding the intermediate stages of its fibrillation and the morphological characteristics of the end-state amyloid fibrils remains limited. Recently, molecular dynamics (MD) simulations based on a hybrid multistate structure-based model, Multi-eGO, have shown promise in capturing the kinetics and mechanism of amyloid fibrillation with high computational efficiency while achieving qualitative agreement with experiments. Here, we utilize the multi-eGO simulation methodology to study the mechanism and kinetics of polyQ fibrillation and the effect of the N17 flanking domain of Huntingtin protein. Aggregation simulations of polyQ produced highly heterogeneous amyloid fibrils with variable-width branched morphologies by incorporating combinations of β-turn, β-arc, and β-strand structures, while the presence of the N17 flanking domain reduces amyloid fibril heterogeneity by favoring β-strand conformations. Our simulations reveal that the presence of N17 domain enhanced aggregation kinetics by promoting the formation of large, structurally stable oligomers. Furthermore, the early-stage aggregation process involves two distinct mechanisms: backbone interactions driving β-sheet formation and side-chain interdigitation. Overall, our study provides detailed insights into fibrillation kinetics, mechanisms, and end-state polymorphism associated with Httex1 amyloid aggregation.
SIGNIFICANCE STATEMENT: Polyglutamine (polyQ) aggregation is central to Huntington's disease and related neurodegenerative disorders. Despite extensive experimental efforts, a complete molecular understanding of this process-from early aggregation events to the origins of fibril polymorphism-has remained elusive, with varied interpretations of complex fibril architectures. Through multiscale simulations, we reveal how polyQ fibrils adopt diverse tertiary and quaternary structures and demonstrate how the N-terminal flanking domain (N17) modulates fibril architecture and accelerates aggregation. Our hybrid multi-eGO simulations capture early-stage fibrillation kinetics and identify distinct structural polymorphs that align with experimental observations. This work provides a molecular framework for understanding amyloid polymorphism and illuminates the role of flanking domains in shaping aggregation pathways- offering valuable insights for therapeutic strategies targeting early toxic intermediates.

DOI: https://doi.org/10.1101/2025.05.19.654960
Elife. 2025 Jun 06. pii: RP96675. [Epub ahead of print]13

Clearance of protein aggregates during cell division.

Shoukang Du, Yuhan Wang, Bowen Chen, Shuangshuang Xie, Kuan Yoow Chan, David C Hay, Ting Gang Chew.

  Protein aggregates are spatially organized and regulated in cells to prevent the deleterious effects of proteostatic stress. Misfolding of proteins in the endoplasmic reticulum (ER) results in aggregate formation, but how the aggregates are processed, especially during cell division is not well understood. Here, we induced proteostatic stress and protein aggregation using a proteostasis reporter, which is prone to misfolding and aggregation in the ER. Unexpectedly, we detected solid-like protein aggregates deposited mainly in the nucleus and surrounded by the ER membrane. The membrane-bound aggregates were then cleared as cells progressed through mitosis and cytokinesis. Aggregate clearance depended on Hsp70 family chaperones in the ER, particularly BiP, and proteasomal activity. The clearance culminated at mitotic exit and required cyclin-dependent kinase 1 (Cdk1) inactivation but was independent of the anaphase-promoting complex (APC/C). The ER reorganization that is active during mitosis and cytokinesis was required for the aggregate clearance. Thus, dividing cells reorganize the ER networks to allow BiP to clear the protein aggregates to maintain proteostasis in the newly divided cells.

Keywords:  ER reorganization; aggregates; cell biology; chaperone; human; mitosis; proteostasis

DOI:  https://doi.org/10.7554/eLife.96675
Front Immunol. 2025 ;16 1574755

Engineered sequestrins inhibit aggregation of pathogenic alpha-synuclein mutants.

Linnea Charlotta Hjelm, Wojciech Paslawski, Christofer Lendel, Siri Flemming Svedmark, Per Svenningsson, Stefan Ståhl, Hanna Lindberg, John Löfblom.

  Misfolding and aggregation of the neuronal protein alpha-synuclein (aSyn) has been identified as a hallmark of Parkinson's disease (PD) pathology and other synucleinopathies. Preventing formation of intracellular aSyn accumulations constitutes a therapeutic strategy against disease development. We recently reported on a new type of affinity protein, denoted Sequestrin, aimed for efficient and stable interactions with aggregation-prone amyloidogenic proteins and peptides. Upon binding, sequestrins interact with the aggregation-prone peptide and form a stabilizing four-stranded beta sheet with similarities to the beta sheet rich structures seen in amyloid fibrils. Here, high-affinity aSyn-binding sequestrins were isolated from a large naïve sequestrin library using phage display technology. The best binders demonstrated dissociation constant, KD, values in the 10 nM-range, and structural rearrangements in both the sequestrin and aSyn protein upon binding. Modelling using AlphaFold, followed by NMR spectroscopy suggested that the sequestrins bind an N-terminal region of aSyn that is critical for amyloidogenic aggregation. In an in vitro aggregation study, the sequestrins demonstrated complete inhibition of aSyn aggregation at equimolar concentrations, including the three familial mutants A30P, E46K, and A53T that are associated with Parkinson's disease and Lewy body dementia.

Keywords:  Parkinson’s disease; affibody molecule; alpha-synuclein; directed evolution; phage display; sequestrin

DOI:  https://doi.org/10.3389/fimmu.2025.1574755
Eur J Neurosci. 2025 Jun;61(11): e70156

The Role of Kinases in Neurodegenerative Diseases: From Pathogenesis to Treatment.

Alkusha Naim, Azhar Mahmood Farooqui, Badruddeen, Mohammad Irfan Khan, Juber Akhtar, Asad Ahmad, Anas Islam.

  Neurodegenerative diseases are characterized by progressive neuronal loss and dysfunction, with protein kinases playing crucial roles in their pathogenesis. This article explores the involvement of protein kinases in these disorders, focusing on their contributions to disease mechanisms, potential as therapeutic targets and challenges in developing effective treatments. In Alzheimer's disease, kinases such as CDK5, GSK3β and MARK4 are implicated in tau hyperphosphorylation and the formation of neurofibrillary tangles. Kinases also regulate amyloid-β processing and plaque formation. In Parkinson's disease, LRRK2, PINK1 and other kinases contribute to α-synuclein pathology, mitochondrial dysfunction and neuroinflammation. LRRK2 inhibitors and PROTACs have shown promise in preclinical models. Huntington's disease involves altered kinase activity, with CK2, GSK3 and MAPK pathways influencing mutant huntingtin toxicity and aggregation. Kinases are also implicated in less common neurodegenerative diseases, such as ALS and spinocerebellar ataxias. Despite the therapeutic potential of targeting kinases, challenges remain, including the complexity of kinase networks, blood-brain barrier permeability and the lack of robust biomarkers. Emerging technologies, such as covalent inhibitors, targeted protein degradation and combination therapies, offer new avenues for addressing these challenges and developing more effective treatments for neurodegenerative diseases.

Keywords:  Alzheimer's disease; Huntington's disease; Parkinson's disease; neurodegenerative diseases; protein kinases; tau phosphorylation

DOI:  https://doi.org/10.1111/ejn.70156
Biochem Biophys Res Commun. 2025 Jun 02. pii: S0006-291X(25)00855-1. [Epub ahead of print]775 152141

The a-type domain of protein disulfide isomerase suppresses amyloid-β aggregation and cytotoxicity.

Masafumi Sakono, Harune Ichida, Tomonao Inobe.

  Abnormal aggregation of amyloid-β (Aβ) peptide and associated neurotoxicity are key pathological hallmarks of Alzheimer's disease. Protein disulfide isomerase (PDI) contains four thioredoxin-like domains arranged as a, b, b', and a' from the N-terminus. The a-type domains (a and a') possess catalytic activity essential for redox regulation, while the b-type domains (b and b') are mainly involved in substrate interactions. This study aimed to elucidate the effects of PDI, an enzyme involved in protein redox control and folding, on Aβ aggregation, focusing on its distinct domains. PDI variants containing the a-type domains potently inhibited Aβ aggregation. Furthermore, an aa' variant effectively stabilized Aβ monomers and significantly reduced Aβ-induced cytotoxicity. Conversely, the b-type domains exhibited no clear inhibitory effect on Aβ aggregation. Moreover, in serum-containing medium, the b-type domains potentially hindered the anti-aggregation function of full-length PDI, possibly through interactions with other proteins. These results indicate that PDI's a-type domains play a central role in inhibiting Aβ aggregation and highlight the aa' variant as a potential candidate for novel therapeutic strategies against Alzheimer's disease.

Keywords:  Aggregation inhibition; Alzheimer's disease; Amyloid β; Protein disulfide isomerase

DOI:  https://doi.org/10.1016/j.bbrc.2025.152141
Nat Rev Drug Discov. 2025 Jun 02.

Lowering pathological α-synuclein.

Sarah Crunkhorn.

DOI: https://doi.org/10.1038/d41573-025-00093-z
bioRxiv. 2025 May 17. pii: 2025.05.16.654576. [Epub ahead of print]

Genetic Code Expansion and Enzymatic Modifications as Accessible Methods for Studying Site-Specific Post-Translational Modifications of Alpha-Synuclein and Tau.

Ibrahim G Saleh, Marie Shimogawa, Jennifer Ramirez, Bernard Abakah, Yarra Venkatesh, Honey Priya James, Ming-Hao Li, Sarah A Louie, Marshall G Lougee, Wai-Kit Chia, Richard B Cooley, Ryan A Mehl, Tobias Baumgart, Robert H Mach, David Eliezer, Elizabeth Rhoades, E James Petersson.

Alpha-synuclein (αS) and tau play important roles in the pathology of Parkinson's Disease and Alzheimer's Disease, respectively, as well as numerous other neurodegenerative diseases. Both proteins are classified as intrinsically disordered proteins (IDPs), as they have no stable structure that underlies their function in healthy tissue, and both proteins are prone to aggregation in disease states. There is substantial interest in understanding the roles that post-translational modifications (PTMs) play in regulating the structural dynamics and function of αS and tau monomers, as well as their propensity to aggregate. While there have been many valuable insights into site-specific effects of PTMs garnered through chemical synthesis and semi-synthesis, these techniques are often outside of the expertise of biochemistry and biophysics laboratories wishing to study αS and tau. Therefore, we have assembled a primer on genetic code expansion and enzymatic modification approaches to installing PTMs into αS and tau site-specifically, including isotopic labeling for NMR and fluorescent labeling for biophysics and microscopy experiments. These methods should be enabling for those wishing to study authentic PTMs in αS or tau as well as the broader field of IDPs and aggregating proteins.

DOI: https://doi.org/10.1101/2025.05.16.654576
bioRxiv. 2025 May 21. pii: 2025.05.20.654652. [Epub ahead of print]

Synaptic proteins that aggregate and degrade slower with aging accumulate in microglia.

Ian H Guldner, Viktoria P Wagner, Patricia Moran Losada, Sophia M Shi, Kelly Chen, Barbara T Meese, Hamilton Oh, Yann Le Guen, Nannan Lu, Pui Shuen Wong, Ning-Sum To, Dylan Garceau, Zimin Guo, Jian Luo, Michael Sasner, Andreas Keller, Andrew C Yang, Tom Cheung, Tony Wyss-Coray.

Neurodegenerative diseases affect 1 in 12 people globally and remain incurable. Central to their pathogenesis is a loss of neuronal protein maintenance and the accumulation of protein aggregates with aging. We engineered bioorthogonal tools which allowed us to tag the nascent neuronal proteome and study its turnover with aging, its propensity to aggregate, and its interaction with microglia. We discovered neuronal proteins degraded on average twice as slowly between 4- and 24-month-old mice with individual protein stability differing between brain regions. Further, we describe the aged neuronal 'aggregome' encompassing 574 proteins, nearly 30% of which showed reduced degradation. The aggregome includes well-known proteins linked to disease as well as a trove of proteins previously not associated with neurodegeneration. Unexpectedly, we found 274 neuronal proteins accumulated in microglia with 65% also displaying reduced degradation and/or aggregation with age. Among these proteins, synaptic proteins were highly enriched, suggesting a cascade of events emanating from impaired synaptic protein turnover and aggregation to the disposal of these proteins, possibly by the engulfment of synapses by microglia. These findings reveal the dramatic loss of neuronal proteome maintenance with aging which could be causal for age-related synapse loss and cognitive decline.

DOI: https://doi.org/10.1101/2025.05.20.654652
Front Chem. 2025 ;13 1569777

Inhibitory effect of Fisetin against the aggregation process of SOD1 E100K mutant: computer-based drug design as a potential therapeutic for ALS disease.

Fatemeh Sadat Seyedi Asl, Nasrin Malverdi, Fatemeh Sadat Ataei Kachouei, Fatemeh Zarei, Shamim Ghiabi, Payam Baziyar, Mohsen Nabi-Afjadi.

  Protein misfolding and aggregation in superoxide dismutase 1 (SOD1) are linked to the neurodegenerative disease amyotrophic lateral sclerosis (ALS). SOD1 mutations have a significant role in the pathophysiology and fast behavior of protopathic proteins in ALS illness. The E100K mutation may be useful in uncovering the pathogenic mechanism of SOD1 associated with ALS. According to several studies, giving small molecule inhibitors made from polyphenolic flavonoid compounds may be a viable treatment strategy for neurological conditions. Using molecular docking and MD simulations, we have identified a potential flavonoid drug that may successfully inhibit SOD1's amyloidogenic activity. Puerarin, Fisetin, and Peonidin provided intriguing pharmacological hints during the initial screening of flavonoids. The Fisetin-E100K complex had a larger residual energy contribution and substantial binding than other flavonoid compounds. The findings showed that, unlike other materials, Fisetin increased the structural stability, hydrophobicity, and flexibility of the mutant while reducing the amount of β-sheets. Furthermore, to distinguish aggregation in the mutant (unbound/bound) states, we displayed modifications in the free energy landscape (FEL). As a result, Fisetin was identified as having therapeutic potential against the E100K, which might make it a viable pharmacological option for the creation of inhibitors that lower the chance of ALS death.

Keywords:  ADMET analysis; ALS; E100K mutant; MD simulation; SOD1 aggregation; natural polyphenols

DOI:  https://doi.org/10.3389/fchem.2025.1569777
J Clin Invest. 2025 Jun 02. pii: e182088. [Epub ahead of print]135(11):

TDP-43 dysregulation of polyadenylation site selection is a defining feature of RNA misprocessing in amyotrophic lateral sclerosis and frontotemporal dementia.

Frederick J Arnold, Ya Cui, Sebastian Michels, Michael R Colwin, Cameron M Stockford, Wenbin Ye, Vidhya Maheswari Jawahar, Karen Jansen-West, Julien Philippe, Ravinder Gulia, Yunzi Gou, Oliver H Tam, Sneha Menon, Wendy G Situ, Saira L Cazarez, Aryan Zandi, Kean Ck Ehsani, Sierra Howard, Dennis W Dickson, Molly Gale Hammell, Mercedes Prudencio, Leonard Petrucelli, Wei Li, Albert R La Spada.

  Nuclear clearance and cytoplasmic aggregation of TAR DNA-binding protein 43 (TDP-43) are observed in many neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Although TDP-43 dysregulation of splicing has emerged as a key event in these diseases, TDP-43 can also regulate polyadenylation; yet this has not been adequately studied. Here, we applied the dynamic analysis of polyadenylation from an RNA-Seq (DaPars) tool to ALS/FTD transcriptome datasets and report extensive alternative polyadenylation (APA) upon TDP-43 alteration in ALS/FTD cell models and postmortem ALS/FTD neuronal nuclei. Importantly, many identified APA genes highlight pathways implicated in ALS/FTD pathogenesis. To determine the functional relevance of APA elicited by TDP-43 nuclear depletion, we examined microtubule affinity regulating kinase 3 (MARK3). Nuclear loss of TDP-43 yielded increased expression of MARK3 transcripts with longer 3' UTRs, corresponding with a change in the subcellular distribution of MARK3 and increased neuronal tau S262 phosphorylation. Our findings define changes in polyadenylation site selection as a previously understudied feature of TDP-43-driven disease pathology in ALS/FTD and highlight a potentially important mechanistic link between TDP-43 dysfunction and tau regulation.

Keywords:  Genetics; Neurodegeneration; Neuroscience; RNA processing

DOI:  https://doi.org/10.1172/JCI182088
Biophys Chem. 2025 May 31. pii: S0301-4622(25)00083-3. [Epub ahead of print]325 107471

Effect of pyrimethanil on aβ42 aggregation mechanisms revealed at single entity level and molecular dynamic simulations.

Nathan Meyer, Nicolas Arroyo, Lois Roustan, Jean-Marc Janot, Véronique Perrier, Joan Torrent, Fabien Picaud, Sebastien Balme.

  This study investigated the impact of pyrimethanil, a fungicide, on the aggregation of amyloid-β 42 (aβ42) peptides in vitro. The findings demonstrated that pyrimethanil accelerated aβ42 aggregation kinetics, as evidenced by thioflavin T (ThT) fluorescence assays in both tube and microplate experiments. A combination of single molecule techniques and molecular dynamics simulations is used to elucidate the complex effects of pyrimethanil on aβ42 aggregation mechanism. Nanopore experiments indicated that pyrimethanil promoted the formation of small oligomers (6-13.5 nm) during the lag phase, which were not detected under control conditions. Confocal fluorescence spectroscopy revealed that pyrimethanil induced the formation of larger β-sheet structured aggregates. In the presence of preformed seeds, pyrimethanil exhibited a dual role by fragmenting existing fibrils into smaller species and enhancing aggregation, likely through combined effects with the newly formed smaller seeds. Molecular dynamics simulations confirmed that pyrimethanil has a higher affinity for fibrils than monomers and weakens monomer-fibril interactions. Overall, this study elucidates the complex effects of pyrimethanil on aβ42 aggregation, involving promotion of primary nucleation, fibril fragmentation, and modulation of monomer-fibril interactions. These findings provide important mechanistic insights into how environmental factors like pesticides may influence amyloid aggregation processes relevant to Alzheimer's disease.

Keywords:  Aggregation; Alzheimer's disease; Amyloid-β; Nanopore; Oligomers

DOI:  https://doi.org/10.1016/j.bpc.2025.107471
eNeuro. 2025 Jun 02. pii: ENEURO.0093-25.2025. [Epub ahead of print]

Generation of iPSC lines with tagged α-synuclein for visualization of endogenous protein in human cellular models of neurodegenerative disorders.

Oskar G Zetterdahl, James A Crowe, Samira Reyhani, Miriam A Güra, Ot Labastida-Botey, Aline Girard, D Sean Froese, Henrik Ahlenius, Isaac Canals.

α-Synuclein is a synaptic protein that accumulates primarily in synucleinopathies and secondarily in certain lysosomal storage disorders. However, its physiological roles in health and disease are not fully understood. In part, this has been hampered by the inability to visualize α-synuclein and its cellular localization, due to the lack of specific antibodies and faithful reporters. Here, we used CRISPR/Cas9-based genome editing to generate human induced pluripotent stem cell (iPSC) lines in which the α-synuclein (SNCA) gene has been tagged with the short HA peptide either at the N-terminus or C-terminus, or with the fluorescent protein mCherry at the C-terminus of the protein. These diverse strategies revealed the C-terminus HA-tag as the best option. C-terminus HA-tagged α-synuclein had unchanged protein expression and did not generate degradation by-products. Importantly, we show that following differentiation to neurons the C-terminus HA-tagged iPSC line had unaffected electrophysiological properties and could be used to visualize accumulation of α-synuclein upon inhibition of lysosomal function and under physiological protein levels. It is our expectation that this line and tagging approach will be very useful in further studies examining α-synuclein aggregation and its role in cellular dysfunction and neurodegeneration.Significance Statement We present an optimal genome editing strategy for incorporating the short peptide HA at the C-terminus of α-synuclein in human induced pluripotent stem cells. We also show that this newly generated C-terminus tagged line can be differentiated towards functional neurons to facilitate visualization of the protein and its accumulation upon inhibition of lysosomal function, which will be useful for studying aggregation in models of neurodegenerative diseases.

DOI: https://doi.org/10.1523/ENEURO.0093-25.2025
Mol Neurodegener. 2025 Jun 04. 20(1): 66

The many connections of UFMylation with Alzheimer's disease: a comprehensive review.

Tingxiang Yan, Benjamin D Clarkson, Zhenkun Lou, Wolfdieter Springer, Fabienne C Fiesel.

Alzheimer's disease (AD) is a complex neurodegenerative disorder that is characterized by the accumulation of pathologic tau and beta-amyloid proteins. UFMylation is an emerging ubiquitin-like post-translational modification that is crucial for healthy brain development. The UFM1 cascade was recently identified as a major modifier of tau aggregation in vitro and in vivo. Moreover, post-mortem AD brain shows pronounced alterations of UFMylation that are significantly associated with pathological tau, suggesting UFM1 might indeed be a modifier of human disease. However, the link between AD and UFMylation is yet to be fully explored. Interestingly, the UFMylation cascade is known to play important roles for several pathways that are known to be altered in AD, such as the DNA damage response, ER homeostasis, autophagy and the immune response. This review discusses the many connections between UFMylation with AD pathogenesis, emphasizing the role of UFMylation in these pathways and their abnormalities in AD. Understanding these connections is important to elucidate molecular mechanisms how UFM1 may impact AD and to uncover novel therapeutic strategies targeting UFMylation pathways for disease modification.

DOI: https://doi.org/10.1186/s13024-025-00855-8
Neuron. 2025 Jun 04. pii: S0896-6273(25)00305-8. [Epub ahead of print]113(11): 1653-1655

Shedding light on the α-synuclein fibril fuzzy coat.

Joel C Watts.

The β-sheet-rich core region of α-synuclein fibrils is important for defining disease manifestation. In this issue of Neuron, Han et al. demonstrate that the comparatively less structured fibril fuzzy coat region also modulates α-synuclein seeding activity in neurons and mice.

DOI: https://doi.org/10.1016/j.neuron.2025.04.022