bims-axbals Biomed News
on Axonal biology and ALS
Issue of 2025–02–23
fifty-four papers selected by
TJ Krzystek, ALS Therapy Development Institute
  1. Nemo-like kinase disrupts nuclear import and drives TDP43 mislocalization in ALS.
  2. Rab27b promotes lysosomal function and alpha-synuclein clearance in neurons.
  3. Purifying and profiling lysosomes to expand understanding of lysosomal dysfunction-associated diseases.
  4. SUMO2/3 conjugation of TDP-43 protects against aggregation.
  5. Doublecortin restricts neuronal branching by regulating tubulin polyglutamylation.
  6. Optineurin-facilitated axonal mitochondria delivery promotes neuroprotection and axon regeneration.
  7. Neuronal Activity-Dependent Gene Dysregulation in C9orf72 i 3 Neuronal Models of ALS/FTD Pathogenesis.
  8. Neuroimaging Techniques in Huntington's Disease: A Critical Review.
  9. Graphene Biosensor Differentiating Sensitive Interactions between Ribonucleic Acid and Dipeptide Repeats in Liquid-Liquid Phase Separation.
  10. Focused-ultrasound-mediated CRISPR-Cas9 gene editing in human induced pluripotent stem cells.
  11. Enterovirus D68 2A protease causes nuclear pore complex dysfunction and motor neuron toxicity.
  12. The role of striatum in controlling waiting during reactive and self-timed behaviors.
  13. Triumphs, Trials, and Future Considerations in Genetic Therapies for Hereditary Neuromuscular Diseases.
  14. Neuronal endolysosomal acidification relies on interactions between transmembrane protein 184B (TMEM184B) and the vesicular proton pump.
  15. Mitochondrial control of ciliary gene expression and structure in striatal neurons.
  16. Re-Analyses of Samples From Amyotrophic Lateral Sclerosis Patients and Controls Identify Many Novel Small RNAs With Diagnostic And Prognostic Potential.
  17. Active microtubule-actin cross-talk mediated by a nesprin-2G-kinesin complex.
  18. Extracellular vesicles efficiently deliver survival motor neuron protein to cells in culture.
  19. Molecular mechanisms and pathological implications of unconventional protein secretion in human disease: from cellular stress to therapeutic targeting.
  20. Calcium release from damaged lysosomes triggers stress granule formation for cell survival.
  21. Glycosphingolipids in neurodegeneration - Molecular mechanisms, cellular roles, and therapeutic perspectives.
  22. Peripheral defects precede neuromuscular pathology in the Smn2B/- mouse model of spinal muscular atrophy.
  23. Proprioceptive synaptic dysfunction is a key feature in mice and humans with spinal muscular atrophy.
  24. Distinctive autophagy/mitophagy biomarker profiles in frontotemporal lobar degeneration and Alzheimer's disease.
  25. Defined culture conditions robustly maintain human stem cell pluripotency, highlighting a role for Ca2+ signaling.
  26. Parkinson's Disease Modeling Using Directly Converted 3D Induced Dopaminergic Neuron Organoids and Assembloids.
  27. Metabolomic and Proteomic Profiling of Serum-Derived Extracellular Vesicles from Early-Stage Amyotrophic Lateral Sclerosis Patients.
  28. The roles of intrinsically disordered proteins in neurodegeneration.
  29. SIRT3-Mediated Deacetylation of DRP1K711 Prevents Mitochondrial Dysfunction in Parkinson's Disease.
  30. A novel lncRNA FAM151B-DT regulates autophagy and degradation of aggregation prone proteins.
  31. Intra-axonal Nanomagnetic Forces Differentially Impact hTau40 Transport Dynamics in Primary Cortical and Hippocampal Neurons.
  32. iPSC-based cell replacement therapy: from basic research to clinical application.
  33. STING-induced noncanonical autophagy regulates endolysosomal homeostasis.
  34. LRRK2, lysosome damage, and Parkinson's disease.
  35. Development of a flexible 3D printed TPU-PVC microfluidic devices for organ-on-a-chip applications.
  36. Endoplasmic reticulum stress and unfolded protein response: Roles in skeletal muscle atrophy.
  37. Cholesterol-mediated Lysosomal Dysfunction in APOE4 Astrocytes Promotes α-Synuclein Pathology in Human Brain Tissue.
  38. Deuterium labeling enables proteome wide turnover kinetics analysis in cell culture.
  39. RNA Interference Targeting Small Heat Shock Protein B8 Failed to Improve Distal Hereditary Motor Neuropathy in the Mouse Model.
  40. Long-term exposure to anti-GluA3 antibodies triggers functional and structural changes in hippocampal neurons.
  41. Huntington's Disease Clinical Trials Update: September 2024.
  42. JAG1 overexpression partially rescues muscle function in a zebrafish model of duchenne muscular dystrophy.
  43. Stress granules as transient reservoirs for autophagy proteins: a key mechanism for plant recovery from heat stress.
  44. Context-specific interaction of the lipid regulator DIP-2 with phospholipid synthesis in axon regeneration and maintenance.
  45. Tsc1 Deletion in Purkinje Neurons Disrupts the Axon Initial Segment, Impairing Excitability and Cerebellar Function.
  46. Small heat shock protein HSPB8 interacts with a pre-fibrillar TDP43 low complexity domain species to delay fibril formation.
  47. TRAM-LAG1-CLN8 family proteins are acyltransferases regulating phospholipid composition.
  48. 3D Bioprinted Coaxial Testis Model Using Human Induced Pluripotent Stem Cells:A Step Toward Bicompartmental Cytoarchitecture and Functionalization.
  49. Ergothioneine controls mitochondrial function and exercise performance via direct activation of MPST.
  50. Staufen2 dysregulation in neurodegenerative disease.
  51. Mechanisms of astrocyte aging in reactivity and disease.
  52. Generation of Functional Brain Region-Specific Neural Spheroids for High Throughput Screening.
  53. Lysosomal Quality Control.
  54. Mannose-6-phosphate-PEG-lipid conjugates improve liposomal uptake.
  1. bioRxiv. 2025 Jan 28. pii: 2025.01.27.635090. [Epub ahead of print]
    Nemo-like kinase disrupts nuclear import and drives TDP43 mislocalization in ALS.
    Michael E Bekier, Emile Pinarbasi, Jack J Mesojedec, Layla Ghaffari, Martina de Majo, Erik Ullian, Mark Koontz, Sarah Coleman, Xingli Li, Elizabeth M H Tank, Jacob Waksmacki, Sami Barmada.
      Cytoplasmic TDP43 mislocalization and aggregation are pathological hallmarks of amyotrophic lateral sclerosis (ALS). However, the initial cellular insults that lead to TDP43 mislocalization remain unclear. In this study, we demonstrate that Nemo-like kinase (NLK)-a proline-directed serine/threonine kinase-promotes the mislocalization of TDP43 and other RNA-binding proteins by disrupting nuclear import. NLK levels are selectively elevated in neurons exhibiting TDP43 mislocalization in ALS patient tissues, while genetic reduction of NLK reduces toxicity in human neuron models of ALS. Our findings suggest that NLK is a promising therapeutic target for neurodegenerative diseases.
    DOI:  https://doi.org/10.1101/2025.01.27.635090
  2. J Neurosci. 2025 Feb 18. pii: e1579242025. [Epub ahead of print]
    Rab27b promotes lysosomal function and alpha-synuclein clearance in neurons.
    Kasandra Scholz, Rudradip Pattanayak, Roschongporn Ekkatine, F Sanders Pair, Amber Nobles, William J Stone, Talene A Yacoubian.
      Alpha-synuclein (αsyn) is the key pathogenic protein implicated in synucleinopathies including Parkinson's Disease (PD) and Dementia with Lewy Bodies (DLB). In these diseases, αsyn is thought to spread between cells where it accumulates and induces pathology; however, mechanisms that drive its propagation or aggregation are poorly understood. We have previously reported that the small GTPase Rab27b is elevated in human PD and DLB and that it can mediate the autophagic clearance and toxicity of αsyn in a paracrine αsyn cell culture model. Here, we expanded our previous work and characterized a role for Rab27b in neuronal lysosomal processing and αsyn clearance. We found that Rab27b KD in this αsyn inducible neuronal model resulted in lysosomal dysfunction and increased αsyn levels in lysosomes. Similar lysosomal proteolytic defects and enzymatic dysfunction were observed in both primary neuronal cultures and brain lysates from male and female Rab27b knockout (KO) mice. αSyn aggregation was exacerbated in Rab27b KO neurons upon treatment with αsyn preformed fibrils. We found no changes in lysosomal counts or lysosomal pH in either model, but we did identify changes in acidic vesicle trafficking and in lysosomal enzyme maturation and localization, which may drive lysosomal dysfunction and promote αsyn aggregation. Rab27b OE enhanced lysosomal activity and reduced insoluble αsyn accumulation. Finally we found elevated Rab27b levels in human postmortem incidental Lewy Body Disease (iLBD) subjects relative to healthy controls. These data suggest a role for Rab27b in neuronal lysosomal activity and identify it as a potential therapeutic target in synucleinopathies.Significance statement Alpha-synuclein aggregation in Parkinson's disease is associated with autophagic-lysosomal dysfunction, yet the molecular mechanisms underlying alpha-synuclein clearance are not well understood. We identified the small GTPase Rab27b as a novel regulator of the lysosomal clearance of alpha-synuclein. Using several alpha-synuclein models, we found that Rab27b knockdown or knockout impairs lysosomal function, increases alpha-synuclein lysosomal accumulation, and increases alpha-synuclein aggregation. Conversely, Rab27b overexpression promotes lysosomal function and reduces alpha-synuclein aggregation. We also identified defects in lysosomal enzyme maturation and localization and acidic vesicle trafficking upon Rab27b loss, which may drive lysosomal dysfunction. These findings suggest that targeting Rab27b could boost lysosomal clearance of alpha-synuclein in synucleinopathies.
    DOI:  https://doi.org/10.1523/JNEUROSCI.1579-24.2025
  3. J Clin Invest. 2025 Feb 17. pii: e188507. [Epub ahead of print]135(4):
    Purifying and profiling lysosomes to expand understanding of lysosomal dysfunction-associated diseases.
    Ali Shilatifard, Issam Ben-Sahra.
      Lysosome storage dysfunction plays a central role in numerous human diseases, but a lack of appropriate tools has hindered lysosomal content profiling in clinical settings. In this issue of the JCI, Saarela et al. introduce a method called tagless LysoIP that enabled rapid isolation of intact lysosomes from blood and brain cells via immunoprecipitation of the endogenous protein TMEM192. Applied to the neurodegenerative lysosomal storage disorder known as Batten disease (caused by mutations in the CLN3 gene), tagless LysoIP revealed substantial accumulation of glycerophosphodiesters (GPDs) in patient lysosomes. These findings highlight the role of CLN3 in GPD clearance and present an innovative method that will enable biomarker discovery and therapeutic advancement in lysosomal diseases.
    DOI:  https://doi.org/10.1172/JCI188507
  4. Sci Adv. 2025 Feb 21. 11(8): eadq2475
    SUMO2/3 conjugation of TDP-43 protects against aggregation.
    Enza Maria Verde, Francesco Antoniani, Laura Mediani, Valentina Secco, Samuele Crotti, Maria Celidea Ferrara, Jonathan Vinet, Aleksandra Sergeeva, Xiao Yan, Carsten Hoege, Cristiana Stuani, Francesca Paron, Tzu-Ting Kao, Rohit Shrivastava, Jolanta Polanowska, Aymeric Bailly, Alessandro Rosa, Eleonora Aronica, Anand Goswami, Neil Shneider, Anthony A Hyman, Emanuele Buratti, Dimitris Xirodimas, Titus M Franzmann, Simon Alberti, Serena Carra.
      Cytosolic aggregation of the RNA binding protein TDP-43 (transactive response DNA-binding protein 43) is a hallmark of amyotrophic lateral sclerosis and frontotemporal dementia. Here, we report that during oxidative stress, TDP-43 becomes SUMO2/3-ylated by the SUMO E3 ligase protein PIAS4 (protein inhibitor of activated STAT 4) and enriches in cytoplasmic stress granules (SGs). Upon pharmacological inhibition of TDP-43 SUMO2/3-ylation or PIAS4 depletion, TDP-43 enrichment in SGs is accompanied by irreversible aggregation. In cells that are unable to assemble SGs, SUMO2/3-ylation of TDP-43 is strongly impaired, supporting the notion that SGs are compartments that promote TDP-43 SUMO2/3-ylation during oxidative stress. Binding of TDP-43 to UG-rich RNA antagonizes PIAS4-mediated SUMO2/3-ylation, while RNA dissociation promotes TDP-43 SUMO2/3-ylation. We conclude that SUMO2/3 protein conjugation is a cellular mechanism to stabilize cytosolic RNA-free TDP-43 against aggregation.
    DOI:  https://doi.org/10.1126/sciadv.adq2475
  5. Nat Commun. 2025 Feb 18. 16(1): 1749
    Doublecortin restricts neuronal branching by regulating tubulin polyglutamylation.
    Muriel Sébastien, Alexandra L Paquette, Emily N P Prowse, Adam G Hendricks, Gary J Brouhard.
      Doublecortin is a neuronal microtubule-associated protein that regulates microtubule structure in neurons. Mutations in Doublecortin cause lissencephaly and subcortical band heterotopia by impairing neuronal migration. We use CRISPR/Cas9 to knock-out the Doublecortin gene in induced pluripotent stem cells and differentiate the cells into cortical neurons. DCX-KO neurons show reduced velocities of nuclear movements and an increased number of neurites early in neuronal development, consistent with previous findings. Neurite branching is regulated by a host of microtubule-associated proteins, as well as by microtubule polymerization dynamics. However, EB comet dynamics are unchanged in DCX-KO neurons. Rather, we observe a significant reduction in α-tubulin polyglutamylation in DCX-KO neurons. Polyglutamylation levels and neuronal branching are rescued by expression of Doublecortin or of TTLL11, an α-tubulin glutamylase. Using U2OS cells as an orthogonal model system, we show that DCX and TTLL11 act synergistically to promote polyglutamylation. We propose that Doublecortin acts as a positive regulator of α-tubulin polyglutamylation and restricts neurite branching. Our results indicate an unexpected role for Doublecortin in the homeostasis of the tubulin code.
    DOI:  https://doi.org/10.1038/s41467-025-56951-2
  6. Nat Commun. 2025 Feb 20. 16(1): 1789
    Optineurin-facilitated axonal mitochondria delivery promotes neuroprotection and axon regeneration.
    Dong Liu, Hannah C Webber, Fuyun Bian, Yangfan Xu, Manjari Prakash, Xue Feng, Ming Yang, Hang Yang, In-Jee You, Liang Li, Liping Liu, Pingting Liu, Haoliang Huang, Chien-Yi Chang, Liang Liu, Sahil H Shah, Anna La Torre, Derek S Welsbie, Yang Sun, Xin Duan, Jeffrey Louis Goldberg, Marcus Braun, Zdenek Lansky, Yang Hu.
      Optineurin (OPTN) mutations are linked to amyotrophic lateral sclerosis (ALS) and normal tension glaucoma (NTG), but a relevant animal model is lacking, and the molecular mechanisms underlying neurodegeneration are unknown. We find that OPTN C-terminus truncation (OPTN∆C) causes late-onset neurodegeneration of retinal ganglion cells (RGCs), optic nerve (ON), and spinal cord motor neurons, preceded by a decrease of axonal mitochondria in mice. We discover that OPTN directly interacts with both microtubules and the mitochondrial transport complex TRAK1/KIF5B, stabilizing them for proper anterograde axonal mitochondrial transport, in a C-terminus dependent manner. Furthermore, overexpressing OPTN/TRAK1/KIF5B prevents not only OPTN truncation-induced, but also ocular hypertension-induced neurodegeneration, and promotes robust ON regeneration. Therefore, in addition to generating animal models for NTG and ALS, our results establish OPTN as a facilitator of the microtubule-dependent mitochondrial transport necessary for adequate axonal mitochondria delivery, and its loss as the likely molecular mechanism of neurodegeneration.
    DOI:  https://doi.org/10.1038/s41467-025-57135-8
  7. bioRxiv. 2025 Jan 27. pii: 2025.01.27.632228. [Epub ahead of print]
    Neuronal Activity-Dependent Gene Dysregulation in C9orf72 i 3 Neuronal Models of ALS/FTD Pathogenesis.
    Layla T Ghaffari, Emily Welebob, Ashley Boehringer, Kelly Cyliax, Piera Pasinelli, Davide Trotti, Aaron R Haeusler.
      The GGGGCC nucleotide repeat expansion (NRE) mutation in the C9orf72 (C9) gene is the most common cause of ALS and FTD. Neuronal activity plays an essential role in shaping biological processes within both healthy and neurodegenerative disease scenarios. Here, we show that at baseline conditions, C9-NRE iPSC-cortical neurons display aberrations in several pathways, including synaptic signaling and transcriptional machinery, potentially priming diseased neurons for an altered response to neuronal stimulation. Indeed, exposure to two pathophysiologically relevant stimulation modes, prolonged membrane depolarization, or a blockade of K + channels, followed by RNA sequencing, induces a temporally divergent activity-dependent transcriptome of C9-NRE cortical neurons compared to healthy controls. This study provides new insights into how neuronal activity influences the ALS/FTD-associated transcriptome, offering a dataset that enables further exploration of pathways necessary for conferring neuronal resilience or degeneration.
    DOI:  https://doi.org/10.1101/2025.01.27.632228
  8. Mov Disord Clin Pract. 2025 Feb 20.
    Neuroimaging Techniques in Huntington's Disease: A Critical Review.
    Mena Farag, Harry Knights, Rachael I Scahill, Peter McColgan, Carlos Estevez-Fraga.
       BACKGROUND: Huntington's disease (HD) is a hereditary neurodegenerative disorder characterized by cognitive, neuropsychiatric and motor symptoms caused by a CAG trinucleotide repeat expansion in the huntingtin gene. Imaging techniques are crucial for understanding HD pathophysiology and monitoring disease progression.
    OBJECTIVES: This review is targeted at general neurologists and movement disorders specialists with an interest in HD and aims to bring complex imaging, including new experimental techniques, closer to the practicing clinician.
    METHODS: We provide a summary of findings from conventional structural, diffusion and functional imaging in HD studies, together with an update on emerging novel techniques, including multiparametric mapping, multi-shell diffusion techniques, ultra-high field 7-Tesla MRI, positron emission tomography and magnetoencephalography.
    RESULTS: Conventional imaging techniques have deepened our understanding of neuropathological progression in HD, from striatal atrophy to widespread cortical and white matter changes. The integration of novel imaging techniques reviewed has further improved our ability to interrogate, quantify and visualize disease-specific alterations with high precision.
    CONCLUSIONS: Novel imaging techniques have promising roles to further our understanding of HD pathology and as imaging markers for clinical trials, disease staging and therapeutic monitoring. Additionally, the synergistic potential of combining imaging modalities with molecular and genetic data, along with wet biomarkers and clinical data, will help provide a complete and comprehensive view of HD pathology and progression.
    Keywords:  7 T MRI; Huntington's disease; MEG; PET; machine learning
    DOI:  https://doi.org/10.1002/mdc3.70010
  9. ACS Appl Mater Interfaces. 2025 Feb 16.
    Graphene Biosensor Differentiating Sensitive Interactions between Ribonucleic Acid and Dipeptide Repeats in Liquid-Liquid Phase Separation.
    Kantaro Kikuchi, Yui Yamazaki, Kohsuke Kanekura, Yuhei Hayamizu.
      Liquid-Liquid Phase Separation (LLPS) plays a crucial role in cell biology and is closely associated with neurodegenerative diseases like Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). Recent studies connect mutations in the C9ORF72 gene to the production of arginine-rich dipeptide repeat proteins (R-DPRs), such as poly(PR) and poly(GR). These R-DPRs disrupt LLPS in membrane-less organelles (MLOs) and contribute to disease pathology. While traditional analysis techniques like nuclear magnetic resonance (NMR), fluorescence recovery after photobleaching (FRAP), and Förster resonance energy transfer (FRET) provide insights into LLPS's role in these diseases, their ability is limited in detecting weak intermolecular interactions within LLPS droplets. This study employs graphene field-effect transistors (GFETs) for their superior sensitivity in detecting these molecular interactions. We immobilized RNA (poly-A) on GFETs and measured the electrical conductivity of GFETs to characterize shifts in the voltage of the charge neutral point in GFETs, allowing for the detection of dipeptide repeat peptides, such as (PR)12, (GR)12, and R12. Our results show that interactions between peptides and RNA require a specific peptide concentration threshold and vary between peptide types. Notably, the minimal conductivity shift suggests that peptides containing proline residues exhibit a nonuniform spatial distribution during interactions with RNA on graphene surfaces. This finding indicates that peptide rigidity induced by prolines plays a vital role in these molecular interactions and their multivalent contacts with RNA, which agrees with findings reported in other recent works. The capability of GFETs to detect these interactions at nanomolar concentrations marks a significant advancement in sensitivity over existing methods. This research sheds light on the mechanisms of LLPS involving R-DPRs and opens avenues for further understanding of related neurodegenerative diseases.
    Keywords:  biosensor; dipeptide repeat proteins; graphene field-effect transistor; liquid−liquid phase separation; molecular interactions
    DOI:  https://doi.org/10.1021/acsami.4c15382
  10. Mol Ther. 2025 Feb 20. pii: S1525-0016(25)00096-6. [Epub ahead of print]
    Focused-ultrasound-mediated CRISPR-Cas9 gene editing in human induced pluripotent stem cells.
    Bernie Simone Owusu-Yaw.
      
    DOI:  https://doi.org/10.1016/j.ymthe.2025.02.006
  11. bioRxiv. 2025 Feb 05. pii: 2025.01.23.632178. [Epub ahead of print]
    Enterovirus D68 2A protease causes nuclear pore complex dysfunction and motor neuron toxicity.
    Katrina M Zinn, Mathew W McLaren, Michael T Imai, Malavika M Jayaram, Jeffrey D Rothstein, Matthew J Elrick.
      The picornavirus Enterovirus D68 (EV-D68) is an important pathogen associated with acute flaccid myelitis (AFM). The pathogenesis of AFM involves infection of spinal motor neurons and motor neuron death, however the mechanisms linking EV-D68 infection to selective neurotoxicity are not well understood. Dysfunction of the nuclear pore complex (NPC) has been implicated in motor neuron injury in neurodegenerative diseases such as amyotrophic lateral sclerosis, and the NPC is also modified by picornavirus proteases during the course of infection. We therefore sought to determine the impact of EV-D68 proteases on NPC structure and function and their role in motor neuron toxicity. We demonstrate widespread disruption of NPC composition by EV-D68 2A and 3C proteases via the direct cleavage of a relatively small number of nucleoporins, notably Nup98 and POM121 by 2A pro . Using reporter systems, we demonstrate that 2A pro inhibits nuclear import and export of protein cargoes and also disrupts the permeability barrier of the NPC, while having no apparent effect on RNA export. We further show that 2A pro is toxic to induced pluripotent stem cell derived motor neurons by demonstrating a rescue of toxicity with 2A pro inhibitor telaprevir at concentrations that are insufficient to inhibit viral replication. This study expands our understanding of EV-D68 neuropathogenesis and provides a rationale for targeting the NPC or 2A pro therapeutically in AFM.
    DOI:  https://doi.org/10.1101/2025.01.23.632178
  12. J Neurosci. 2025 Feb 14. pii: e1820242025. [Epub ahead of print]
    The role of striatum in controlling waiting during reactive and self-timed behaviors.
    Qiang Zheng, Yujing Liu, Yue Huang, Jiaming Cao, Xuanning Wang, Jianing Yu.
      The ability to wait before responding is crucial for many cognitive functions, including reaction time tasks, where one must resist premature actions before the stimulus and respond quickly once the stimulus is presented. However, the brain regions governing waiting remain unclear. Using localized excitotoxic lesions, we investigated the roles of the motor cortex (MO) and sensorimotor dorsolateral striatum (DLS) in male rats performing a conditioned lever release task with variable delays. Neural activity in both MO and DLS showed similar firing patterns during waiting and responding periods. However, only bilateral DLS lesions caused a sustained increase in premature (anticipatory) responses, whereas bilateral MO lesions primarily prolonged reaction times. In a self-timing version of the task, where rats held a lever for a fixed delay before release, DLS lesions caused a leftward shift in response timing, leading to persistently greater premature responses. These waiting deficits were accompanied by reduced motor vigor, such as slower reward-orienting locomotion. Our findings underscore the critical role of the sensorimotor striatum in regulating waiting behavior in timing-related behaviors.Significant Statement Waiting is essential for the temporal control of actions, as many cognitive behaviors-whether stimulus-driven or internally planned-require withholding a response until the appropriate time. However, the neural substrates of waiting remain less understood. Using targeted lesions, we identified the dorsolateral striatum as a crucial region for waiting in both reaction time and self-timing tasks. Lesions in this area caused a persistent increase in premature responses across tasks. In contrast, motor cortex lesions, despite its neurons showing similar activity patterns to the striatum during waiting, did not result in a lasting increase in premature responses; instead, they led to a long-term increase in reaction time.
    DOI:  https://doi.org/10.1523/JNEUROSCI.1820-24.2025
  13. Mo Med. 2025 Jan-Feb;122(1):122(1): 46-52
    Triumphs, Trials, and Future Considerations in Genetic Therapies for Hereditary Neuromuscular Diseases.
    W David Arnold, Kajri Majithia.
      Neuromuscular diseases include conditions that affect the spinal motor neurons, peripheral nerves, neuromuscular junctions, and muscles, and they can result from acquired and inherited causes. The number of genetic therapies targeting the inherited causes of neuromuscular diseases has surged in the last decade. This review aims to highlight the current state of genetic therapies within the framework of precision medicine, focusing on the achievements and the gaps that remain. A major emphasis is on spinal muscular atrophy, Duchenne muscular dystrophy, and amyotrophic lateral sclerosis, as these neuromuscular diseases have seen tremendous recent advancements. We will also discuss the future considerations necessary to accelerate the development of next-generation genetic therapies and enhance therapeutic outcomes for patients with neuromuscular diseases.
  14. bioRxiv. 2025 Feb 02. pii: 2025.02.01.635992. [Epub ahead of print]
    Neuronal endolysosomal acidification relies on interactions between transmembrane protein 184B (TMEM184B) and the vesicular proton pump.
    Elizabeth B Wright, Erik G Larsen, Marco Padilla-Rodriguez, Paul R Langlais, Martha R C Bhattacharya.
      Disruption of endolysosomal acidification is a hallmark of several neurodevelopmental and neurodegenerative disorders. Impaired acidification causes accumulation of toxic protein aggregates and disrupts neuronal homeostasis, yet the molecular mechanisms regulating endolysosomal pH in neurons remain poorly understood. A critical regulator of lumenal acidification is the vacuolar ATPase (V-ATPase), a proton pump whose activity depends on dynamic assembly of its V0 and V1 subdomains. In this study, we identify transmembrane protein 184B (TMEM184B) as a novel regulator of endolysosomal acidification in neurons. TMEM184B is an evolutionarily conserved 7-pass transmembrane protein required for synaptic structure and function, and sequence variation in TMEM184B causes neurodevelopmental disorders, but the mechanism for this effect is unknown. We performed proteomic analysis of TMEM184B-interacting proteins and identified enrichment of components involved in endosomal trafficking and function, including the V-ATPase. TMEM184B localizes to early and late endosomes, further supporting a role in the endosomal system. Loss of TMEM184B results in significant reductions in endolysosomal acidification within cultured mouse cortical neurons. This alteration in pH is associated with impaired assembly of the V-ATPase V0 and V1 subcomplexes in the TMEM184B mutant mouse brain, suggesting a mechanism by which TMEM184B promotes flux through the endosomal pathway. Overall, these findings identify a new contributor in maintaining endosomal function and provide a mechanistic basis for disrupted neuronal function in human TMEM184B-associated nervous system disorders.
    Significance Statement: Endolysosomal acidification is essential for neuronal protein homeostasis, yet its regulation in neurons remains poorly understood. Here, we identify TMEM184B as a key regulator of this process, establishing its first known cellular role. We show that TMEM184B interacts with vacuolar ATPase (V-ATPase) components and promotes the assembly of its V0 and V1 subdomains, facilitating lumenal acidification. Loss of TMEM184B disrupts endolysosomal pH in neurons, potentially impairing proteostasis. These findings reveal a critical function for TMEM184B in neuronal maintenance and provide mechanistic insight into its link to neurological disorders. This work advances our understanding of endolysosomal regulation and suggests TMEM184B regulation could improve outcomes in diseases involving lysosomal dysfunction.
    DOI:  https://doi.org/10.1101/2025.02.01.635992
  15. J Physiol. 2025 Feb 18.
    Mitochondrial control of ciliary gene expression and structure in striatal neurons.
    Dogukan H Ulgen, Alessandro Chioino, Olivia Zanoletti, Albert Quintana, Elisenda Sanz, Carmen Sandi.
      Mitochondria play essential metabolic roles and are increasingly understood to interact with other organelles, influencing cellular function and disease. Primary cilia, as sensory and signalling organelles, are crucial for neuronal communication and function. Emerging evidence suggests that mitochondria and primary cilia may interact to regulate cellular processes, as recently shown in brain cells such as astrocytes. Here, we investigated whether mitochondria also regulate primary cilia in neurons, focusing on molecular pathways linking both organelles and structural components within cilia. We employed a cross-species, molecular pathway-focused approach to explore connections between mitochondrial and ciliary pathways in neurons, revealing strong associations suggesting coordinated functionality. Furthermore, we found that viral-induced downregulation of the mitochondrial fusion gene mitofusin 2 (Mfn2) in dopamine D1 receptor-expressing medium spiny neurons (D1-MSNs) of the nucleus accumbens (NAc) altered ciliary gene expression, with Crocc - the gene encoding rootletin - showing the most pronounced downregulation. This reduction in Crocc expression was linked to decreased levels of rootletin protein, a key structural component of the ciliary rootlet. Notably, viral-mediated overexpression of rootletin restored ciliary complexity and elongation, without compromising neuronal adaptation to Mfn2 downregulation. Our findings provide novel evidence of a functional mitochondria-cilia interaction in neurons, specifically in striatal D1-MSNs. These results reveal a previously unrecognized role of mitochondrial dynamics in regulating ciliary structure in neurons, with potential implications for neuropsychiatric and neurodegenerative disease mechanisms. KEY POINTS: Mitochondria are cell structures known for producing energy but are also emerging as regulators of other cellular components, including primary cilia, antenna-like structures involved in cell communication. Previous studies suggest that mitochondria may influence cilia structure and function, including in astrocytes. However, this has not been explored in neurons. This study shows that natural variation in mitochondrial molecular pathways correlates with primary cilia pathways in striatal medium spiny neurons in both rats and mice. Reducing expression of mitofusin 2 (Mfn2), a key mitochondrial protein involved in fusion and mitochondria-endoplasmic reticulum interactions, changes specific molecular ciliary pathways, notably including Crocc, a gene essential for cilia structure, and reduces the levels of its protein product, rootletin, which supports cilia integrity. Our findings reveal an important role for mitochondria in regulating ciliary structure in neurons, highlighting a potential pathway for mitochondrial regulation of neuronal signalling.
    Keywords:  RiboTag sequencing; cilium; gene manipulation; mitochondria; mitofusin 2; single nucleus RNA sequencing
    DOI:  https://doi.org/10.1113/JP287948
  16. Mol Neurobiol. 2025 Feb 21.
    Re-Analyses of Samples From Amyotrophic Lateral Sclerosis Patients and Controls Identify Many Novel Small RNAs With Diagnostic And Prognostic Potential.
    Phillipe Loher, Eric Londin, Hristelina Ilieva, Piera Pasinelli, Isidore Rigoutsos.
      Amyotrophic lateral sclerosis (ALS) is a highly heterogeneous disease for which accurate diagnostic and prognostic biomarkers are needed. Toward this goal, we reanalyzed two published collections of datasets generated from the plasma and serum of ALS patients and controls. We profiled these datasets for isoforms of microRNAs (miRNAs) known as isomiRs, transfer RNA-derived fragments (tRFs), and ribosomal RNA-derived fragments (rRFs), placing all remaining reads into a group labeled "not-itrs." We found that plasma and serum are rich in isomiRs (canonical, non-canonical, and non-templated), tRFs, rRFs, and members of an emerging class of small RNAs known as Y RNA-derived fragments (yRFs). In both analyzed collections, we found many isomiRs, tRFs, rRFs, and yRFs that are differentially abundant between patients and controls. We also performed a survival analysis that considered Riluzole treatment status, demographics (age at onset, age at enrollment, sex), and disease characteristics (ALSFRS, rD50, onset type) and found many of the differentially abundant small RNAs to be associated with survival time, with some of these associations being independent of Riluzole treatment. Unexpectedly, many not-itrs that did not map to the human genome mapped exactly to sequences from the SILVA database of ribosomal DNAs (rDNAs). Not-itrs from the plasma datasets mapped primarily to rDNAs from the order of Burkholderiales, and several of them were associated with patient survival. Not-itrs from the serum datasets also showed support for rDNA from Burkholderiales but a stronger support for rDNAs from the fungi group of the Nucletmycea taxon. The findings suggest that many previously unexplored small non-coding RNAs, including human isomiRs, tRFs, rRFs, and yRFs, could potentially serve as novel diagnostic and prognostic biomarkers for ALS.
    Keywords:  ALS; Amyotrophic lateral sclerosis; Burkholderiales; Diagnostics; Nucletmycea; Prognostics; Y RNAs; isomiRs; miRNAs; rRFs; rRNAs; tRFs; tRNAs; yRFs
    DOI:  https://doi.org/10.1007/s12035-025-04747-2
  17. Sci Adv. 2025 Feb 21. 11(8): eadq4726
    Active microtubule-actin cross-talk mediated by a nesprin-2G-kinesin complex.
    Natalie Sahabandu, Kyoko Okada, Aisha Khan, Daniel Elnatan, Daniel A Starr, Kassandra M Ori-McKenney, G W Luxton, Richard J McKenney.
      Nesprin-2 Giant (N2G) is a large integral membrane protein that physically connects the nucleus to the cytoskeleton, but how N2G performs this activity to maintain nuclear positioning and drive nuclear movement is unclear. This study investigates N2G's role in nucleocytoskeletal coupling, a process critical for cellular function and development. We uncover multiple roles for N2G, including its activity as an F-actin bundler, an adapter that activates kinesin-1 motors, and a mediator of cytoskeletal cross-talk. Notably, N2G directly links kinesin-1 to F-actin, enabling the transport of actin filaments along microtubule tracks, establishing active cross-talk between the actin and microtubule cytoskeletons. These findings provide crucial insights into nuclear movement, advancing our understanding of fundamental cellular processes and their implications in development and disease.
    DOI:  https://doi.org/10.1126/sciadv.adq4726
  18. Sci Rep. 2025 Feb 15. 15(1): 5674
    Extracellular vesicles efficiently deliver survival motor neuron protein to cells in culture.
    Charlotte A René, Robin J Parks.
      Spinal Muscular Atrophy (SMA) is a genetic neuromuscular disorder caused by homozygous mutation or deletion of the survival motor neuron 1 (SMN1) gene, leading to a low quantity of SMN protein in cells. This depletion of SMN protein preferentially leads to death of motor neurons and, consequently, muscle atrophy, in addition to defects in many other peripheral tissues. SMN protein is naturally loaded into extracellular vesicles (EVs), which are sub-micron-sized, membrane-bound particles released from all cell types. The innate ability of EVs to deliver cargo to recipient cells has caused these vesicles to gain interest as therapeutic delivery vehicles. In this study, we show that adenovirus-mediated overexpression of SMN protein in HepG2 cells leads to the release of EVs loaded with high levels of SMN protein into conditioned medium. Application of this medium to recipient cells in tissue culture led to uptake of the SMN protein, which subsequently transited to the nucleus and co-localized with Gemin2 protein, forming nuclear gem-like structures similar to the native SMN protein. Overall, this work demonstrates that SMN protein can be delivered to cells through EVs, which holds promise as a potential therapy for patients with SMA.
    Keywords:  Extracellular vesicles; Neuromuscular disease; Nuclear gems; Spinal muscular atrophy; Therapeutic delivery; Therapeutic protein
    DOI:  https://doi.org/10.1038/s41598-025-90083-3
  19. Mol Biol Rep. 2025 Feb 15. 52(1): 236
    Molecular mechanisms and pathological implications of unconventional protein secretion in human disease: from cellular stress to therapeutic targeting.
    Yukun Liu, Haolin Zhang, Xianghua Li, Tianlong He, Wenting Zhang, Cuicui Ji, Juan Wang.
      Unconventional protein secretion (UcPS) encompasses diverse non-canonical cellular export mechanisms that operate independently of the classical secretory pathway, representing a crucial cellular response to various physiological and pathological conditions. This comprehensive review synthesizes current understanding of UcPS mechanisms, particularly focusing on their roles in disease pathogenesis and progression. Recent advances in proteomics and cellular biology have revealed that UcPS facilitates the secretion of various biomedically significant proteins, including inflammatory mediators, growth factors, and disease-associated proteins, through multiple pathways such as membrane translocation, secretory lysosomes, and membrane-bound organelles. Notably, dysregulation of UcPS mechanisms has been implicated in various pathological conditions, including chronic inflammation, neurodegenerative disorders, and malignant transformation. We critically evaluate the molecular machinery governing UcPS, its regulation under cellular stress, and its contribution to disease mechanisms. Furthermore, we examine emerging therapeutic strategies targeting UcPS pathways, highlighting both opportunities and challenges in developing novel interventional approaches.
    Keywords:  Cancer; Inflammation; Neurodegenerative diseases; Unconventional protein secretion
    DOI:  https://doi.org/10.1007/s11033-025-10316-6
  20. Autophagy. 2025 Feb 17.
    Calcium release from damaged lysosomes triggers stress granule formation for cell survival.
    Aravinth Kumar Jayabalan, Aanuoluwakiitan Ayeni, Jingyue Jia.
      Lysosomes are essential membrane-bound organelles that integrate intracellular needs and external signals through multiple functions, including autophagy-mediated degradation and MTORC1 signaling. The integrity of the lysosomal membrane is therefore crucial for maintaining cellular homeostasis. Various endogenous and exogenous factors can damage lysosomes, contributing to diseases such as infections, cancer, and neurodegeneration. In response, cells mount defensive mechanisms to cope with such stress, including the formation of stress granules (SGs) - membraneless organelles composed of RNAs and protein complexes. While SGs have emerged as key players in repairing damaged lysosomes, how lysosomal damage triggers their formation and influences cell fate remains unclear. Here we report that the calcium signal from damaged lysosomes mediates SG formation and protects cells from lysosomal damage-induced cell death. Mechanistically, calcium leakage from damaged lysosomes signals the recruitment of calcium-activating protein PDCD6IP/ALIX and its partner PDCD6/ALG2. This complex recruits protein kinase EIF2AK2/PKR and its activator PRKRA/PACT, which phosphorylates translation initiator factor EIF2S1, stalling global translation initiation. This translation arrest leads to the accumulation of inactive messenger ribonucleoprotein complexes (mRNPs), resulting in SG formation. Cells deficient in SG formation show increased cell death when exposed to lysosomal damage from disease-associated factors including SARS-CoV-2ORF3a, adenovirus, malarial pigment, proteopathic MAPT/tau, or environmental hazards. Collectively, this study reveals how damaged lysosomes signal through calcium to trigger SG assembly, promoting cell survival. This establishes a novel link between membrane-bound and membraneless organelles, with implications for diseases involving lysosomal damage and SG dysfunction.
    Keywords:  Calcium signaling; cell survival; lysosomal damage; stress granules
    DOI:  https://doi.org/10.1080/15548627.2025.2468910
  21. Neurobiol Dis. 2025 Feb 18. pii: S0969-9961(25)00067-1. [Epub ahead of print] 106851
    Glycosphingolipids in neurodegeneration - Molecular mechanisms, cellular roles, and therapeutic perspectives.
    Andreas J Hülsmeier.
      Neurodegenerative diseases, including Alzheimer's (AD), Parkinson's (PD), Huntington's (HD), and amyotrophic lateral sclerosis (ALS), are characterized by progressive neuronal loss and pose significant global health challenges. Glycosphingolipids (GSLs), critical components of neuronal membranes, regulate signal transduction, membrane organization, neuroinflammation, and lipid raft functionality. This review explores GSL roles in neural development, differentiation, and neurogenesis, along with their dysregulation in neurodegenerative diseases. Aberrations in GSL metabolism drive key pathological features such as protein aggregation, neuroinflammation, and impaired signaling. Specific GSLs, such as GM1, GD3, and GM3, influence amyloid-beta aggregation in AD, α-synuclein stability in PD, and mutant huntingtin toxicity in HD. Therapeutic strategies targeting GSL metabolism, such as GM1 supplementation and enzyme modulation, have demonstrated potential to mitigate disease progression. Further studies using advanced lipidomics and glycomics may support biomarker identification and therapeutic advancements. This work aims to highlight the translational potential of GSL research for diagnosing and managing devastating neurodegenerative conditions.
    Keywords:  Cellular signaling; Gangliosides; Glycosphingolipids; Lipid rafts; Neurodgeneration
    DOI:  https://doi.org/10.1016/j.nbd.2025.106851
  22. J Neuromuscul Dis. 2024 Nov;11(6): 1200-1210
    Peripheral defects precede neuromuscular pathology in the Smn2B/- mouse model of spinal muscular atrophy.
    Aoife Reilly, Ariane Beauvais, Majd Al-Aarg, Rebecca Yaworski, Emma R Sutton, Simon Thebault, Rashmi Kothary.
       BACKGROUND: Spinal Muscular Atrophy (SMA) is an inherited neurodegenerative disease caused by the loss or mutation of the survival motor neuron 1 (SMN1) gene. Though classically regarded as a motor neuron disorder, reports are increasingly describing the involvement of non-neuronal organs in SMA. The Smn2B/- mouse is a model of SMA that displays a peripheral phenotype including metabolic defects.
    OBJECTIVE: Here, we characterized several neuronal and non-neuronal defects in the Smn2B/- mouse throughout development to better understand the progression of the disease and the relationship between tissue defects.
    METHODS: We collected tissues from mutant Smn2B/- mice and Smn2B/+ littermate controls at several timepoints and evaluated spinal cord motor neuron loss, neuromuscular junction pathology, muscle fiber size, liver steatosis, and pancreatic islet cell composition. Blood glucose and plasma neurofilament light chain (NfL) were also measured.
    RESULTS: Smn2B/- mice displayed several peripheral defects prior to motor neuron loss and showed early elevations in neurofilament light chain (NfL) protein.
    CONCLUSIONS: This work provides an important framework for guiding future research with this mouse model and demonstrates that the liver may be an early target in the development of SMA.
    Keywords:  animal models; biomarkers; blood glucose; liver; metabolism; motor neurons; muscles; neurofilament protein; neuromuscular junction; pancreas
    DOI:  https://doi.org/10.1177/22143602241288036
  23. Brain. 2025 Feb 21. pii: awaf074. [Epub ahead of print]
    Proprioceptive synaptic dysfunction is a key feature in mice and humans with spinal muscular atrophy.
    Christian M Simon, Nicolas Delestrée, Jacqueline Montes, Leonie Sowoidnich, Florian Gerstner, Erick Carranza, Jannik M Buettner, John G Pagiazitis, Genis Prat-Ortega, Scott Ensel, Serena Donadio, Vanessa Dreilich, Maria J Carlini, Jose L Garcia, Panagiotis Kratimenos, Wendy K Chung, Charlotte J Sumner, Louis H Weimer, Elvira Pirondini, Marco Capogrosso, Livio Pellizzoni, Darryl C De Vivo, George Z Mentis.
      Spinal muscular atrophy (SMA) is a neurodegenerative disease characterized by a varying degree of severity that correlates with the reduction of SMN protein levels. Motor neuron degeneration and skeletal muscle atrophy are hallmarks of SMA, but it is unknown whether other mechanisms contribute to the spectrum of clinical phenotypes. Here, through a combination of physiological and morphological studies in mouse models and SMA patients, we identify dysfunction and loss of proprioceptive sensory synapses as key signatures of SMA pathology. We demonstrate that Type 3 SMA patients exhibit impaired proprioception, and their proprioceptive synapses are dysfunctional as measured by the neurophysiological test of the Hoffmann reflex (H-reflex). We further show moderate loss of spinal motor neurons along with reduced excitatory afferent synapses and altered potassium channel expression in motor neurons from Type 1 SMA patients. These are conserved pathogenic events found in both severely affected patients and mouse models. Lastly, we report that improved motor function and fatigability in ambulatory Type 3 SMA patients and mouse models treated with SMN-inducing drugs correlate with increased function of sensory-motor circuits that can be accurately captured by the H-reflex assay. Thus, sensory synaptic dysfunction is a clinically relevant event in SMA, and the H-reflex is a suitable assay to monitor disease progression and treatment efficacy of motor circuit pathology.
    Keywords:  motor neuron; neurodegenerative disease; proprioception; sensory synapses; sensory-motor circuit; spinal muscular atrophy
    DOI:  https://doi.org/10.1093/brain/awaf074
  24. Acta Neuropathol Commun. 2025 Feb 20. 13(1): 37
    Distinctive autophagy/mitophagy biomarker profiles in frontotemporal lobar degeneration and Alzheimer's disease.
    Kateřina Veverová, Alžběta Katonová, Hana Horáková, Jan Laczó, Francesco Angelucci, Jakub Hort, Sofie Lautrup, Evandro Fei Fang, Martin Vyhnálek.
      Maintaining cellular homeostasis by removing damaged and senescent mitochondria, a process termed mitophagy, is crucial in preventing Alzheimer's disease (AD) and represents a promising therapeutic target. Our previous research revealed altered mitophagy biomarkers, such as increased CSF and serum PINK1 and serum BNIP3L and decreased serum TFEB levels, indicating impaired autophagy-lysosomal degradation in the AD continuum. However, the role of autophagy/mitophagy in frontotemporal lobar degeneration (FTLD) remains unclear. This study investigated the biomarkers of autophagy/mitophagy and lysosomal biogenesis (PINK1, ULK1, BNIP3L, and TFEB) in biofluids (CSF and serum) from 308 biomarker-defined individuals across the FTLD continuum (FTLD-dementia, n = 29; FTLD-MCI, n = 33) and compared them with those across the AD continuum (MCI-AD, n = 100; AD-dementia, n = 100) and cognitively unimpaired (CU) controls (n = 46) recruited from Czech Brain Aging Study. Additionally, we compared the mitophagy biomarkers across different FTLD clinical subtypes (frontal, semantic and nonfluent variant) with CU, and explored the association between mitophagy biomarkers and clinical phenotypes of FTLD (biomarkers of tau, biomarkers of neurodegeneration, cognition and ATN profile).Our findings indicated a significantly lower CSF PINK1 and ULK1 levels in FTLD compared to AD, with FTLD dementia showing particularly low CSF PINK1 levels compared to AD-dementia. Conversely, CSF ULK1 levels were higher in FTLD-MCI compared to AD-dementia. Serum analyses revealed lower PINK1 and higher TFEB levels in FTLD dementia compared to AD dementia. This study provides compelling evidence of distinct alterations in autophagy/mitophagy biomarkers between FTLD and AD, indicating that these neurodegenerative diseases may affect the cellular waste disposal system through different pathways. This is the first study to explore mitophagy biomarkers in human CSF and serum in FTLD, opening avenues for further research and potential clinical applications.
    Keywords:  Autophagy; Frontotemporal lobar degeneration; MAPT; Neurocognitive impairment; PINK1, TDP-43, TFEB
    DOI:  https://doi.org/10.1186/s40478-025-01954-9
  25. Commun Biol. 2025 Feb 18. 8(1): 255
    Defined culture conditions robustly maintain human stem cell pluripotency, highlighting a role for Ca2+ signaling.
    Ilse Eidhof, Benjamin Ulfenborg, Malin Kele, Mansoureh Shahsavani, Dania Winn, Per Uhlén, Anna Falk.
      Induced pluripotent stem cells (iPSCs) have significant potential for disease modeling and cell therapies. However, their wide-spread application has faced challenges, including batch-to-batch variabilities, and notable distinctions when compared to embryonic stem cells (ESCs). Some of these disparities can stem from using undefined culture conditions and the reprogramming procedure, however, the precise mechanisms remain understudied. Here, we compared gene expression data from over 100 iPSC and ESC lines cultivated under undefined and defined conditions. Defined conditions significantly reduced inter-PSC line variability, irrespective of PSC cell type, highlighting the importance of standardization to minimize PSC biases. This variability is concurrent with decreased somatic cell marker and germ layer differentiation gene expression and increased Ca2+-binding protein expression. Moreover, SERCA pump inhibition highlighted an important role for intracellular Ca2+ activity in maintaining pluripotency gene expression under defined conditions. Further understanding of these processes can help standardize and improve defined hPSC culture conditions.
    DOI:  https://doi.org/10.1038/s42003-025-07658-z
  26. Adv Sci (Weinh). 2025 Feb 18. e2412548
    Parkinson's Disease Modeling Using Directly Converted 3D Induced Dopaminergic Neuron Organoids and Assembloids.
    Hongwon Kim, Soi Kang, Byounggook Cho, Saemin An, Yunkyung Kim, Jongpil Kim.
      Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons and the accumulation of α-synuclein aggregates, yet current models inadequately mimic the complex human brain environment. Recent advances in brain organoid models offer a more physiologically relevant platform for studying PD, however, iPSC-derived brain organoids require long maturation times and may not accurately represent the aged brain's epigenetics and cellular contexts, limiting their applicability for modeling late-onset diseases like PD. In this study, a novel approach for generating 3D-induced dopaminergic (iDA) neuron organoids directly from human fibroblasts is presented. It is confirmed that these 3D iDA organoids more closely resemble the aged human brain and accurately replicate PD pathologies. Furthermore, this model is extended by incorporating astrocytes to create 3D iDA neuron-astrocyte assembloids, recognizing the critical role of glial cells in neurodegenerative processes. It is identified that PD assembloids incorporating control astrocytes with A53T mutant iDAs demonstrated the neuroprotective effects of healthy astrocytes. In contrast, A53T mutant astrocytes progressively contributed to neuronal degeneration and synucleinopathy in 3D-iDA assembloids. These findings suggest that directly converted 3D-iDA organoids and assembloids provide a robust and physiologically relevant model for studying PD pathogenesis and evaluating therapeutic interventions.
    Keywords:  3D assembloids; induced dopaminergic neuron organoids; parkinson's disease
    DOI:  https://doi.org/10.1002/advs.202412548
  27. J Mol Neurosci. 2025 Feb 15. 75(1): 21
    Metabolomic and Proteomic Profiling of Serum-Derived Extracellular Vesicles from Early-Stage Amyotrophic Lateral Sclerosis Patients.
    Yara Al Ojaimi, Nicolas Vallet, Audrey Dangoumau, Débora Lanznaster, Clement Bruno, Antoine Lefevre, Samira Osman, Camille Dupuy, Patrick Emond, Patrick Vourc'h, Philippe Corcia, Zuzana Krupova, Charlotte Veyrat-Durebex, Hélène Blasco.
      The identification of reliable biomarkers for amyotrophic lateral sclerosis (ALS) is an unmet medical need for the development of diagnostic and therapeutic strategies. Brain-derived extracellular vesicles (EVs) have been described in peripheral blood serum and used as a direct readout of the status of the central nervous system. Here, we aimed to explore exosome-enriched EVs (referred to simply as EVs) from ALS patients via omics analysis at an early disease stage. Serum EVs were obtained from 9 healthy controls and 9 ALS patients. After EV purification, proteomic (LC‒MS/MS followed by TimsTOF Pro Mass Spectrometry) and metabolomic (Q Exactive mass spectrometer) analyses were performed. No differences in the size or concentration of EVs were observed between the controls and ALS patients. Proteomic analysis revealed 45 proteins differentially expressed in the EVs of ALS patients compared with those of controls. Metabolomic analysis revealed several distinctly represented metabolites involved in the citrate cycle and complex lipid metabolism between patients and controls. Interomics correlation analysis revealed 2 modules that were strongly associated with ALS and included several lipid metabolism-related proteins and metabolites. This study is the first to evaluate EVs by integrated proteomics and metabolomics in early-stage ALS patients, highlighting the technological progress in global inter-omics explorations of small biological samples. The differences observed in the levels of several exosomal proteins and metabolites, including phospholipids, could be used to identify serum biomarkers and novel players involved in ALS pathogenesis.
    Keywords:  Amyotrophic lateral sclerosis; Biomarkers; Extracellular vesicles; Omics
    DOI:  https://doi.org/10.1007/s12031-025-02315-w
  28. Biochim Biophys Acta Gen Subj. 2025 Feb 13. pii: S0304-4165(25)00017-0. [Epub ahead of print]1869(4): 130772
    The roles of intrinsically disordered proteins in neurodegeneration.
    Kagistia Hana Utami, Satoru Morimoto, Yasue Mitsukura, Hideyuki Okano.
      Neurodegenerative diseases such as Amyotrophic Lateral Sclerosis, Alzheimer's disease, Parkinson's disease, and Huntington's disease share a common pathological hallmark: the accumulation of misfolded proteins, particularly involving intrinsically disordered proteins (IDPs) like TDP-43, FUS, Tau, α-synuclein, and Huntingtin. These proteins undergo pathological aggregation, forming toxic inclusions that disrupt cellular function. The dysregulation of proteostasis mechanisms, including the ubiquitin-proteasome system (UPS), ubiquitin-independent proteasome system (UIPS), autophagy, and molecular chaperones, exacerbates these proteinopathies by failing to clear misfolded proteins effectively. Emerging therapeutic strategies aim to restore proteostasis through proteasome activators, autophagy enhancers, and chaperone-based interventions to prevent the toxic accumulation of IDPs. Additionally, understanding liquid-liquid phase separation (LLPS) and its role in stress granule dynamics offers novel insights into how aberrant phase transitions contribute to neurodegeneration. By targeting the molecular pathways involved in IDP aggregation and proteostasis regulation, and better understanding the specificity of each component, research in this area will pave the way for innovative therapeutic approaches to combat these neurodegenerative diseases. This review discusses the molecular mechanisms underpinning IDP pathology, highlights recent advancements in drug discovery, and explores the potential of targeting proteostasis machinery to develop effective therapies.
    Keywords:  Aggregation; Autophagy; Chaperone; Intrinsically disordered proteins; Liquid-liquid phase separation; Neurodegenerative diseases; Proteostasis
    DOI:  https://doi.org/10.1016/j.bbagen.2025.130772
  29. Adv Sci (Weinh). 2025 Feb 20. e2411235
    SIRT3-Mediated Deacetylation of DRP1K711 Prevents Mitochondrial Dysfunction in Parkinson's Disease.
    Ye Xi, Kai Tao, Xiaomin Wen, Dayun Feng, Zifan Mai, Hui Ding, Honghui Mao, Mingming Wang, Qian Yang, Jie Xiang, Jie Zhang, Shengxi Wu.
      Dysregulation of mitochondrial dynamics is a key contributor to the pathogenesis of Parkinson's disease (PD). Aberrant mitochondrial fission induced by dynamin-related protein 1 (DRP1) causes mitochondrial dysfunction in dopaminergic (DA) neurons. However, the mechanism of DRP1 activation and its role in PD progression remain unclear. In this study, Mass spectrometry analysis is performed and identified a significant increased DRP1 acetylation at lysine residue 711 (K711) in the mitochondria under oxidative stress. Enhanced DRP1K711 acetylation facilitated DRP1 oligomerization, thereby exacerbating mitochondrial fragmentation and compromising the mitochondrial function. DRP1K711 acetylation also affects mitochondrial DRP1 recruitment and fission independent of canonical S616 phosphorylation. Further analysis reveals the critical role of sirtuin (SIRT)-3 in deacetylating DRP1K711, thereby regulating mitochondrial dynamics and function. SIRT3 agonists significantly inhibit DRP1K711 acetylation, rescue DA neuronal loss, and improve motor function in a PD mouse model. Conversely, selective knockout of SIRT3 in DA neurons exacerbates DRP1K711 acetylation, leading to increased DA neuronal damage, neuronal death, and worsened motor dysfunction. Notably, this study identifies a novel mechanism involving aberrant SIRT3-mediated DRP1 acetylation at K711 as a key driver of mitochondrial dysfunction and DA neuronal death in PD, revealing a potential target for PD treatment.
    Keywords:  DRP1K711; Parkinson's disease; SIRT3; acetylation; mitochondrial dysfunction; oxidative stress
    DOI:  https://doi.org/10.1002/advs.202411235
  30. medRxiv. 2025 Jan 24. pii: 2025.01.22.25320997. [Epub ahead of print]
    A novel lncRNA FAM151B-DT regulates autophagy and degradation of aggregation prone proteins.
    Arun Renganathan, Miguel A Minaya, Matthew Broder, Isabel Alfradique-Dunham, Michelle Moritz, Reshma Bhagat, Jacob Marsh, Anthony Verbeck, Grant Galasso, Emma Starr, David A Agard, Carlos Cruchaga, Celeste M Karch.
      Neurodegenerative diseases share common features of protein aggregation along with other pleiotropic traits, including shifts in transcriptional patterns, neuroinflammation, disruptions in synaptic signaling, mitochondrial dysfunction, oxidative stress, and impaired clearance mechanisms like autophagy. However, key regulators of these pleotropic traits have yet to be identified. Here, we discovered a novel long non-coding RNA (lncRNA), FAM151B-DT , that is reduced in a stem cell model of frontotemporal dementia with tau inclusions (FTLD-tau) and in brains from FTLD-tau, progressive supranuclear palsy, Alzheimer's disease, and Parkinson's disease patients. We show that silencing FAM151B-DT in vitro is sufficient to enhance tau aggregation. To begin to understand the mechanism by which FAM151B-DT mediates tau aggregation and contributes to several neurodegenerative diseases, we deeply characterized this novel lncRNA and found that FAM151B-DT resides in the cytoplasm where it interacts with tau, α-synuclein, HSC70, and other proteins enriched in protein homeostasis. When silenced, FAM151B-DT blocks autophagy, leading to the accumulation of tau and α-synuclein. Importantly, we discovered that increasing FAM151B-DT expression is sufficient to promote autophagic flux, reduce phospho-tau and α-synuclein, and reduce tau aggregation. Overall, these findings pave the way for further exploration of FAM151B-DT as a promising molecular target for several neurodegenerative diseases.
    DOI:  https://doi.org/10.1101/2025.01.22.25320997
  31. ACS Nano. 2025 Feb 18.
    Intra-axonal Nanomagnetic Forces Differentially Impact hTau40 Transport Dynamics in Primary Cortical and Hippocampal Neurons.
    Mackenna K Landis, Anja Kunze.
      A crucial aspect of neural engineering is the ability to manipulate proteins that are substantially involved in axonal outgrowth and maintenance. Previous work in this field has shown that applying low-magnitude (piconewton) forces to early stage neurons can result in altered distributions of critical structural proteins, such as the microtubule-associated protein Tau. Uncovering the mechanisms of Tau redistribution could provide a tool for manipulating dysregulated forms of the protein. This study examined how the transport of Tau responded to intra-axonal nanomagnetic forces (NMFs) in primary cortical and hippocampal neurons. High magnification, live cell fluorescent imaging was employed to visualize the transport of both full-length human Tau (hTau40) and amine-terminated, starch-coated fluorescent magnetic nanoparticles (afMNPs) to observe how these cell-internal forces could impact the transport of hTau40 within the axon. Here, we found that afMNPs acted by pulling on hTau40 puncta under NMF application, especially within cortical cells, where afMNPs were more likely to be found within the axon. Forces greater than 1 pN enabled differentiated transport speeds and displacement of hTau40 based on relative force direction. This data indicates that NMF can be utilized to engineer hTau40 transport, even in cells at later stages of maturation.
    Keywords:  Magnetic Nanoparticles; Nanomagnetic Forces; Neuronal Cytoskeleton; Primary Rat Brain Cell Cultures; Protein Transport; hTau40
    DOI:  https://doi.org/10.1021/acsnano.4c14767
  32. Cytotherapy. 2025 Feb 01. pii: S1465-3249(25)00053-2. [Epub ahead of print]
    iPSC-based cell replacement therapy: from basic research to clinical application.
    Jun Takahashi.
      The advancement of induced pluripotent stem cell (iPSC) technology has revolutionized regenerative medicine, enabling breakthroughs in disease modeling, drug discovery, and cell replacement therapies. This review examines the progression of iPSC-based regenerative medicine, focusing on cell replacement therapy and mechanisms like the Replacement Effect, which is crucial for long-term tissue regeneration. Using Parkinson's disease as a key example, it discusses the induction of midbrain dopaminergic neurons from iPSCs and the importance of precise signaling for safety and efficacy. By demonstrating the integration and safety of these cells, animal studies have paved the way for clinical trials. This review highlights the need for strategic collaboration among stakeholders-regulatory authorities, research and medical staff, and industry-to ensure successful clinical applications. iPSC technology's ongoing evolution holds significant promise for broader therapeutic applications and improved patient outcomes.
    Keywords:  cell replacement therapy; clinical trial; induced pluripotent stem cells; preclinical study
    DOI:  https://doi.org/10.1016/j.jcyt.2025.01.015
  33. Proc Natl Acad Sci U S A. 2025 Feb 25. 122(8): e2415422122
    STING-induced noncanonical autophagy regulates endolysosomal homeostasis.
    Tuozhi Huang, Chenglong Sun, Fenghe Du, Zhijian J Chen.
      The cGAS-STING pathway mediates innate immune responses to cytosolic DNA. In addition to its well-established role in inducing inflammatory cytokines, activation of the cGAS-STING pathway also induces noncanonical autophagy, a process involving the conjugation of the ATG8 family of ubiquitin-like proteins to membranes of the endolysosomal system. The mechanisms and functions of STING-induced autophagy remain poorly understood. In this study, we demonstrated that STING activation induced formation of pH-elevated Golgi-derived vesicles that led to ATG16L1 and V-ATPase-dependent noncanonical autophagy. We showed that STING-induced noncanonical autophagy resulted in activation of the MiT/TFE family of transcription factors (TFEB, TFE3, and MITF), which regulate lysosome biogenesis. We found that lipidation of the ATG8 proteins, particularly GABARAPs, inhibited phosphorylation of MiT/TFE transcription factors by mTORC1. The lipidated GABARAPs bound to the Folliculin-interacting proteins (FNIPs), thereby sequestering the FNIP-folliculin protein complexes from activating mTORC1, resulting in dephosphorylation and nuclear translocation of MiT/TFE transcription factors. Furthermore, we found that STING-induced autophagy activated Leucine-rich repeat kinase 2 (LRRK2), a protein implicated in Parkinson's disease, through GABARAPs lipidation. We further showed that STING-induced autophagy induced ALIX-mediated ESCRT machinery recruitment to mitigate endolysosomal perturbation. These results reveal the multifaceted functions of STING-induced noncanonical autophagy in regulating endolysosomal homeostasis.
    Keywords:  ESCRT; STING; TFEB; autophagy; cGAS
    DOI:  https://doi.org/10.1073/pnas.2415422122
  34. Curr Opin Cell Biol. 2025 Feb 20. pii: S0955-0674(25)00020-1. [Epub ahead of print]93 102482
    LRRK2, lysosome damage, and Parkinson's disease.
    Amanda Bentley-DeSousa, Devin Clegg, Shawn M Ferguson.
      Limited understanding of regulatory mechanisms controlling LRRK2 kinase activity has hindered insights into both its normal biology and how its dysregulation contributes to Parkinson's disease. Fortunately, recent years have yielded an increased understanding of how LRRK2 kinase activity is dynamically regulated by recruitment to endolysosomal membranes. Notably, multiple small GTPases from the Rab family act as both activators and substrates of LRRK2. Additionally, it was recently discovered that LRRK2 is recruited to, and activated at, stressed or damaged lysosomes through an interaction with GABARAP via the CASM (conjugation of ATG8 to single membranes) pathway. These discoveries position LRRK2 within the rapidly growing field of lysosomal damage and repair mechanisms, offering important insights into lysosome biology and the pathogenesis of Parkinson's disease.
    DOI:  https://doi.org/10.1016/j.ceb.2025.102482
  35. Sci Rep. 2025 Feb 19. 15(1): 6125
    Development of a flexible 3D printed TPU-PVC microfluidic devices for organ-on-a-chip applications.
    Rodi Kado Abdalkader, Satoshi Konishi, Takuya Fujita.
      The development of cost-effective, flexible, and scalable microfluidic devices is crucial for advancing organ-on-a-chip (OoC) technology for drug discovery and disease modeling applications. In this study, we present a novel 3D-printed flexible microfluidic device (3D-FlexTPU-MFD) fabricated through a one-step fused deposition modeling (FDM) process using thermoplastic polyurethane (TPU) as the printing filament and polyvinyl chloride (PVC) as the bonding substrate. The device's compatibility was evaluated with various cell types, including human primary myoblasts, human primary endothelial cells (HUVEC), and human iPSC-derived optic vesicle (OV) organoids. Myoblasts cultured within the device exhibited high viability, successful differentiation, and the formation of aligned myotube bundles, outperforming conventional well-plate cultures. Additionally, iPSC-derived OV organoids-maintained viability, displayed neurite outgrowth, and sustained expression of the eye marker PAX6. These results demonstrate that the 3D-FlexTPU-MFD effectively supports cell growth, differentiation, and alignment, making it a promising platform for tissue modeling and OoC applications in future.
    DOI:  https://doi.org/10.1038/s41598-025-90470-w
  36. Biochem Pharmacol. 2025 Feb 12. pii: S0006-2952(25)00061-9. [Epub ahead of print]234 116799
    Endoplasmic reticulum stress and unfolded protein response: Roles in skeletal muscle atrophy.
    Yanan Ji, Quan Jiang, Bingqian Chen, Xin Chen, Aihong Li, Dingding Shen, Yuntian Shen, Hua Liu, Xiaowei Qian, Xinlei Yao, Hualin Sun.
      Skeletal muscle atrophy is commonly present in various pathological states, posing a huge burden on society and patients. Increased protein hydrolysis, decreased protein synthesis, inflammatory response, oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress (ERS) and unfolded protein response (UPR) are all important molecular mechanisms involved in the occurrence and development of skeletal muscle atrophy. The potential mechanisms of ERS and UPR in skeletal muscle atrophy are extremely complex and have not yet been fully elucidated. This article elucidates the molecular mechanisms of ERS and UPR, and discusses their effects on different types of muscle atrophy (muscle atrophy caused by disuse, cachexia, chronic kidney disease (CKD), diabetes mellitus (DM), amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), spinal and bulbar muscular atrophy (SBMA), aging, sarcopenia, obesity, and starvation), and explores the preventive and therapeutic strategies targeting ERS and UPR in skeletal muscle atrophy, including inhibitor therapy and drug therapy. This review aims to emphasize the importance of endoplasmic reticulum (ER) in maintaining skeletal muscle homeostasis, which helps us further understand the molecular mechanisms of skeletal muscle atrophy and provides new ideas and insights for the development of effective therapeutic drugs and preventive measures for skeletal muscle atrophy.
    Keywords:  ERS; Skeletal muscle atrophy; Therapy; UPR
    DOI:  https://doi.org/10.1016/j.bcp.2025.116799
  37. bioRxiv. 2025 Feb 14. pii: 2025.02.09.637107. [Epub ahead of print]
    Cholesterol-mediated Lysosomal Dysfunction in APOE4 Astrocytes Promotes α-Synuclein Pathology in Human Brain Tissue.
    Louise A Mesentier-Louro, Camille Goldman, Alain Ndayisaba, Alice Buonfiglioli, Rikki B Rooklin, Braxton R Schuldt, Abigail Uchitelev, Vikram Khurana, Joel W Blanchard.
      The pathological hallmark of neurodegenerative disease is the aberrant post-translational modification and aggregation of proteins leading to the formation of insoluble protein inclusions. Genetic factors like APOE4 are known to increase the prevalence and severity of tau, amyloid, and α-Synuclein inclusions. However, the human brain is largely inaccessible during this process, limiting our mechanistic understanding. Here, we developed an iPSC-based 3D model that integrates neurons, glia, myelin, and cerebrovascular cells into a functional human brain tissue (miBrain). Like the human brain, we found pathogenic phosphorylation and aggregation of α-Synuclein is increased in the APOE4 miBrain. Combinatorial experiments revealed that lipid-droplet formation in APOE4 astrocytes impairs the degradation of α-synuclein and leads to a pathogenic transformation that seeds neuronal inclusions of α-Synuclein. Collectively, this study establishes a robust model for investigating protein inclusions in human brain tissue and highlights the role of astrocytes and cholesterol in APOE4 -mediated pathologies, opening therapeutic opportunities.
    DOI:  https://doi.org/10.1101/2025.02.09.637107
  38. bioRxiv. 2025 Jan 31. pii: 2025.01.30.635596. [Epub ahead of print]
    Deuterium labeling enables proteome wide turnover kinetics analysis in cell culture.
    Lorena Alamillo, Dominic C M Ng, Jordan Currie, Alexander Black, Boomathi Pandi, Vyshnavi Manda, Jay Pavelka, Peyton Schaal, Joshua G Travers, Timothy A McKinsey, Maggie P Y Lam, Edward Lau.
      The half-life of proteins is tightly regulated and underlies many cellular processes. It remains unclear the extent to which proteins are dynamically synthesized and degraded in different cell types and cell states. We introduce an improved D 2 O labeling workflow and apply it to examine the landscape of protein turnover in pluripotent and differentiating human induced pluripotent stem cells (hiPSC). The majority of hiPSC proteins show minimal turnover beyond cell doubling rates, but we also identify over 100 new fast-turnover proteins not previously described as short-lived. These include proteins that function in cell division and cell cycle checkpoints, that are enriched in APC/C and SPOP degrons, and that are depleted upon pluripotency exit. Differentiation rapidly shifts the set of fast-turnover proteins toward including RNA binding and splicing proteins. The ability to identify fast-turnover proteins in different cell cultures also facilitates secretome analysis, as exemplified by studies of hiPSC-derived cardiac myocytes and primary human cardiac fibroblasts. The presented workflow is broadly applicable to protein turnover studies in diverse primary, pluripotent, and transformed cells.
    DOI:  https://doi.org/10.1101/2025.01.30.635596
  39. J Gene Med. 2025 Feb;27(2): e70013
    RNA Interference Targeting Small Heat Shock Protein B8 Failed to Improve Distal Hereditary Motor Neuropathy in the Mouse Model.
    Leen Vendredy, Vicky De Winter, Jonas Van Lent, Jasmien Orije, Tatiana Da Silva Authier, Istvan Katona, Bob Asselbergh, Elias Adriaenssens, Joachim Weis, Marleen Verhoye, Vincent Timmerman.
       BACKGROUND: Missense mutations in the HSPB8 gene, encoding the small heat shock protein B8, cause distal hereditary motor neuropathy (dHMN) or an axonal form of Charcot-Marie-Tooth disease (CMT subtype 2L). Mice expressing mutant Hspb8 (Lys141Asn) mimic the human disease, whereas mice lacking Hspb8 show no overt phenotype. We aimed to design an RNA interference treatment strategy that rescues the mutant HSPB8 neuronal and muscle phenotype in patient-derived motor neurons and in a knock-in mouse model of CMT2L/dHMN.
    METHODS: We optimized RNA interference sequences targeting both human HSPB8 and mouse HspB8 transcripts with the aim to alleviate disease symptoms. We used human induced pluripotent stem cells and the Hspb8 knock-in mouse model. We designed lenti- and adeno-associated viral vectors that contained the short-hairpin RNA constructs. We performed expression and microscopy studies, magnetic resonance imaging, behaviour analysis and electrophysiology.
    RESULTS: In CMT2L patient-derived induced pluripotent stem cells differentiated towards motor neurons, reducing the HSPB8 expression with a short-hairpin RNA (shRNA), directed towards the 3' untranslated region (3'UTR), ameliorated the morphology and fragmentation of mitochondria. The AAV9-mediated treatment of the 3'UTR shRNA construct, under neuron-specific regulation, in Hspb8 knock-in mice showed inconclusive results towards functional improvement upon expression studies, magnetic resonance imaging and neuropathological findings.
    CONCLUSIONS: Given the limited beneficial effect of the treatment, the RNA interference-mediated reduction of HSPB8/Hspb8 expression might not be the best therapeutic strategy to treat dHMN/CMT2L, unless a higher viral load and earlier treatment can be applied to the mouse model.
    Keywords:  Charcot–Marie–Tooth neuropathy; RNA interference; adeno‐associated virus; magnetic resonance imaging; small heat shock protein
    DOI:  https://doi.org/10.1002/jgm.70013
  40. Neurobiol Dis. 2025 Feb 13. pii: S0969-9961(25)00059-2. [Epub ahead of print]207 106843
    Long-term exposure to anti-GluA3 antibodies triggers functional and structural changes in hippocampal neurons.
    Maria Italia, Alessio Spinola, Barbara Borroni, Monica DiLuca, Fabrizio Gardoni.
      Autoantibodies targeting the GluA3 subunit of AMPA receptors (AMPARs) are implicated in various neurological disorders, including Rasmussen's encephalitis, epilepsy, and frontotemporal dementia. However, their precise role in disease pathology remains insufficiently understood. This study investigated the long-term effects of human anti-GluA3 antibodies (anti-GluA3 hIgGs) on neuronal morphology and function using primary rat hippocampal neurons. We found that long-term exposure to anti-GluA3 hIgGs leads to the delocalisation of GluA3-containing AMPARs at extrasynaptic sites. This molecular event is correlated to dendritic arbor reorganisation, characterised by increased complexity near the soma and progressive simplification in distal regions as well as an increase in the number of shorter dendrites and a corresponding loss of longer ones, thus suggesting altered dendritic pruning dynamics. The altered neuronal architecture was accompanied by an increase in the number of dendritic spines and a modification of their morphology, indicating relevant changes in synaptic connectivity. Functionally, anti-GluA3 hIgGs significantly enhanced NMDA receptor-mediated postsynaptic Ca2+ currents and increased nuclear levels of phosphorylated cAMP response element-binding protein (CREB), indicating altered signal transduction. Overall, our study provides critical insights into the role of anti-GluA3 hIgGs in disease and potentially identifies new therapeutic targets for pathological conditions where they are present.
    Keywords:  AMPA receptors; Autoantibodies; Calcium/glutamate transients; Neuronal morphology
    DOI:  https://doi.org/10.1016/j.nbd.2025.106843
  41. J Huntingtons Dis. 2024 Nov;13(4): 409-418
    Huntington's Disease Clinical Trials Update: September 2024.
    Mena Farag, Sarah J Tabrizi, Edward J Wild.
      In this edition of the Huntington's Disease Clinical Trials Update, we expand on the ongoing extension study of PTC518 from PTC Therapeutics, including 12-month interim results from the parent study. We also discuss 24-month interim results from uniQure's AMT-130 program and 28-week follow-up results from Wave Life Sciences' SELECT-HD clinical trial of WVE-003. Additionally, we provide a comprehensive listing of all currently registered and ongoing clinical trials in Huntington's disease.
    Keywords:  Huntington's disease; clinical trials
    DOI:  https://doi.org/10.1177/18796397241293955
  42. J Genet. 2025 ;pii: 2. [Epub ahead of print]104
    JAG1 overexpression partially rescues muscle function in a zebrafish model of duchenne muscular dystrophy.
    Vishakha Nesari, Suresh Balakrishnan, Upendra Nongthomba.
      Duchenne muscular dystrophy (DMD) is a severe genetic disorder characterized by progressive muscle degeneration and loss of function due to the absence of dystrophin. In this study, we utilized a zebrafish model with a dmd gene knockout to explore the therapeutic potential of JAG1 overexpression in mitigating DMD-associated muscle dysfunction. Dystrophic zebrafish larvae displayed significant impairments in muscle function, evidenced by reduced swimming abilities, decreased birefringence, and disrupted β-dystroglycan localization, indicative of structural degeneration. Overexpression of JAG1, achieved via plasmid injection, partially restored muscle function, as reflected by improvements in stride length and total swimming distance. However, the structural integrity of slow oxidative muscle fibers remained largely unaffected, with a functional decline from 4 to 8 days post-fertilization (dpf) being more indicative of disease progression than structural changes. These findings suggest that the rescue effect of JAG1 overexpression may not be due to the preservation of slow oxidative fibers but rather through a mechanism that reduces susceptibility to contraction-induced injury. Notably, our study faced limitations related to the control of JAG1 expression levels and tissue specificity. Our results highlight the complexity of DMD pathology, where muscle structure and function do not always correlate, emphasizing the need for refined functional assays to better assess therapeutic outcomes. By incorporating functional recovery assessments at 8-10 dpf, zebrafish models can serve as more predictive preclinical tools, potentially enhancing the translational relevance of findings and reducing risks for patients in clinical trials. This study investigates how increasing the levels of a protein called JAG1 can help improve muscle function in a zebrafish model of DMD. By showing partial recovery of muscle activity, the findings suggest new therapeutic strategies that could potentially slow disease progression and improve patient outcomes.
  43. Autophagy. 2025 Feb 19. 1-3
    Stress granules as transient reservoirs for autophagy proteins: a key mechanism for plant recovery from heat stress.
    Lei Feng, Xibao Li, Wenjin Shen, Caiji Gao.
      Stress granules (SGs) are transient, non-membrane-bound cytoplasmic condensates that form in response to environmental stresses, serving as protective reservoirs for mRNAs and proteins. In plants, SGs play a crucial role in stress adaptation, but their relationship with macroautophagy/autophagy, a key process for degrading damaged organelles and misfolded proteins, remains poorly understood. In a recent study, we revealed that key autophagy proteins, including components of the ATG1-ATG13 kinase complex, the class III phosphatidylinositol 3-kinase (PtdIns3K) complex, and the ATG8-PE system, translocate to SGs during heat stress (HS) in Arabidopsis thaliana. Using biochemical, cell biological and genetic approaches, we demonstrated that ATG proteins accumulate on HS-induced SGs and are released to the cytosol upon SG disassembly during the post-HS recovery stage. This process facilitates rapid autophagy activation. Notably, a SG-deficient mutant (ubp1abc) exhibits delayed autophagy activation and impaired clearance of ubiquitinated protein aggregates, highlighting the importance of SGs in regulating autophagy. Our findings uncover a novel mechanism by which SGs sequester autophagy proteins during stress, ensuring their rapid availability for stress recovery, and provide new insights into the interplay between SGs and autophagy in plant stress responses.Abbreviation: ATG, autophagy related; HS, heat stress; PtdIns3K, phosphatidylinositol 3-kinase; RBP47B, RNA-binding protein 47B; SG, stress granule; UBP1, ubiquitin-specific protease 1.
    Keywords:  ATG8; Arabidopsis thaliana; UBP1; autophagy; heat stress; stress granules
    DOI:  https://doi.org/10.1080/15548627.2025.2465395
  44. bioRxiv. 2025 Feb 08. pii: 2025.02.06.636954. [Epub ahead of print]
    Context-specific interaction of the lipid regulator DIP-2 with phospholipid synthesis in axon regeneration and maintenance.
    Seungmee Park, Yishi Jin, Andrew D Chisholm.
      Neurons maintain their morphology over prolonged periods of adult life with limited regeneration after injury. C. elegans DIP-2 is a conserved regulator of lipid metabolism that affects axon maintenance and regeneration after injury. Here, we investigated genetic interactions of dip-2 with mutants in genes involved in lipid biosynthesis and identified roles of phospholipids in axon regrowth and maintenance. CEPT-2 and EPT-1 are enzymes catalyzing the final steps in the de novo phospholipid synthesis (Kennedy) pathway. Loss of function mutants of cept-2 or ept-1 show reduced axon regrowth and failure to maintain axon morphology. We demonstrate that CEPT-2 is cell-autonomously required to prevent age-related axonal defects. Interestingly, loss of function in dip-2 led to suppression of the axon regrowth phenotype observed in either cept-2 or ept-2 mutants, suggesting that DIP-2 acts to counterbalance phospholipid synthesis. Our findings reveal the genetic regulation of lipid metabolism to be critical for axon maintenance under injury and during aging.
    Article Summary: Little is known about how adult neurons live long with limited regenerative capacity. This study investigates the role of lipid metabolism in sustaining neuronal health in C. elegans. Mutating phospholipid synthetic genes impairs axon regrowth after injury. Lack of DIP-2, a lipid regulator, restores regrowth, suggesting DIP-2 counterbalances phospholipid synthesis. Moreover, neuronal phospholipid synthesis is essential for preventing age-dependent axonal defects. These findings reveal phospholipid biosynthesis is key to axon integrity during aging and injury. As lipid metabolism is implicated in neurological disorders, this study serves as an entry point into investigating neuronal lipid biology under various conditions.
    DOI:  https://doi.org/10.1101/2025.02.06.636954
  45. bioRxiv. 2025 Feb 01. pii: 2025.01.31.635932. [Epub ahead of print]
    Tsc1 Deletion in Purkinje Neurons Disrupts the Axon Initial Segment, Impairing Excitability and Cerebellar Function.
    Samuel P Brown, Achintya K Jena, Joanna J Osko, Joseph L Ransdell.
      Loss-of-function mutations in tuberous sclerosis 1 ( TSC1 ) are prevalent monogenic causes of autism spectrum disorder (ASD). Selective deletion of Tsc1 from mouse cerebellar Purkinje neurons has been shown to cause several ASD-linked behavioral impairments, which are linked to reduced Purkinje neuron repetitive firing rates. We used electrophysiology methods to investigate why Purkinje neuron-specific Tsc1 deletion ( Tsc1 mut/mut ) impairs Purkinje neuron firing. These studies revealed a depolarized shift in action potential threshold voltage, an effect that we link to reduced expression of the fast-transient voltage-gated sodium (Nav) current in Tsc1 mut/mut Purkinje neurons. The reduced Nav currents in these cells was associated with diminished secondary immunofluorescence from anti-pan Nav channel labeling at Purkinje neuron axon initial segments (AIS). Interestingly, anti-ankyrinG immunofluorescence was also found to be significantly reduced at the AIS of Tsc1 mut/mut Purkinje neurons, suggesting Tsc1 is necessary for the organization and functioning of the Purkinje neuron AIS. An analysis of the 1 st and 2 nd derivative of the action potential voltage-waveform supported this hypothesis, revealing spike initiation and propagation from the AIS of Tsc1 mut/mut Purkinje neurons is impaired compared to age-matched control Purkinje neurons. Heterozygous Tsc1 deletion resulted in no significant changes in the firing properties of adult Purkinje neurons, and slight reductions in anti-pan Nav and anti-ankyrinG labeling at the Purkinje neuron AIS, revealing deficits in Purkinje neuron firing due to Tsc1 haploinsufficiency are delayed compared to age-matched Tsc1 mut/mut Purkinje neurons. Together, these data reveal the loss of Tsc1 impairs Purkinje neuron firing and membrane excitability through the dysregulation of proteins necessary for AIS organization and function.
    DOI:  https://doi.org/10.1101/2025.01.31.635932
  46. bioRxiv. 2025 Jan 30. pii: 2025.01.28.635368. [Epub ahead of print]
    Small heat shock protein HSPB8 interacts with a pre-fibrillar TDP43 low complexity domain species to delay fibril formation.
    Khaled M Jami, Daniel C Farb, Kayla M Osumi, Catelynn C Shafer, Sophie Criscione, Dylan T Murray.
      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 are protective, but can rigidify, leading to amyloid-like fibril formation, a hallmark of the disease pathology. Key proteins dictating stress granule formation and disassembly, such as TDP43, contain low-complexity (LC) domains that drive fibril formation. HSPB8, a small heat shock protein, plays a critical role modulating stress granule fluidity, preventing aggregation and promoting degradation of misfolded proteins. We examined the interaction between HSPB8 and the TDP43 LC using thioflavin T (ThT) and fluorescence polarization (FP) aggregation assays, fluorescence microscopy and photobleaching experiments, and crosslinking mass spectrometry (XL-MS). Our results indicate that HSPB8 delays TDP43 LC aggregation through domain-specific interactions with fibril nucleating species, without affecting fibril elongation rates. These findings provide mechanistic insight into how ATP-independent chaperones mediate LC domain aggregation and provide a basis for investigating how the TDP43 LC subverts chaperone activity in neurodegenerative disease.
    Significance Statement: ATP-independent chaperones facilitate clearance of aggregated proteins through autophagy. This study provides insight into the molecular mechanism by which small heat shock proteins interact with the aggregation-prone low complexity protein domains of RNA-binding proteins linked to neurodegenerative disease pathologies. The results provide a foundation for designing improved chaperones as therapeutics and illustrate a methodology to identify regions in low complexity domains for targeted drug development in the context of neurodegenerative disease.
    DOI:  https://doi.org/10.1101/2025.01.28.635368
  47. Sci Adv. 2025 Feb 21. 11(8): eadr3723
    TRAM-LAG1-CLN8 family proteins are acyltransferases regulating phospholipid composition.
    Pradeep K Sheokand, Andrew M James, Benjamin Jenkins, Pawel K Lysyganicz, Denis Lacabanne, Martin S King, Edmund R S Kunji, Symeon Siniossoglou, Albert Koulman, Michael P Murphy, Kasparas Petkevicius.
      The diversity of cellular phospholipids, crucial for membrane homeostasis and function, arises from enzymatic remodeling of their fatty acyl chains. In this work, we reveal that poorly understood TRAM-LAG1-CLN8 domain (TLCD)-containing proteins are phospholipid remodeling enzymes. We demonstrate that TLCD1 is an evolutionarily conserved lysophosphatidylethanolamine acyltransferase, which regulates cellular phospholipid composition and generates previously undescribed fatty acid and thiamine (vitamin B1) esters as its secondary products. Furthermore, we establish that human TLCD protein CLN8, mutations of which cause fatal neurodegenerative Batten disease, is a lysophosphatidylglycerol acyltransferase. We show that CLN8 catalyzes the essential step in the biosynthesis of bis(monoacylglycero)phosphate, a phospholipid critical for lysosome function. Our study unveils a family of acyltransferases integral to cellular membrane phospholipid homeostasis and human disease.
    DOI:  https://doi.org/10.1126/sciadv.adr3723
  48. Adv Healthc Mater. 2025 Feb 16. e2402606
    3D Bioprinted Coaxial Testis Model Using Human Induced Pluripotent Stem Cells:A Step Toward Bicompartmental Cytoarchitecture and Functionalization.
    Meghan A Robinson, Sonia Hy Kung, Khaled Ym Youssef, Kali M Scheck, Robert H Bell, Funda Sar, Anne M Haegert, M Mahdi Asmae, Changfeng Cheng, Salina V Yeack, Bhairvi T Mathur, Feng Jiang, Colin C Collins, Faraz Hach, Stephanie M Willerth, Ryan K Flannigan.
      Fertility preservation following pediatric cancer therapy programs has become a major avenue of infertility research. In vitro spermatogenesis (IVS) aims to generate sperm from banked prepubertal testicular tissues in a lab setting using specialized culture conditions. While successful using rodent tissues, progress with human tissues is limited by the scarcity of human prepubertal testicular tissues for research. This study posits that human induced pluripotent stem cells (hiPSCs) can model human prepubertal testicular tissue to facilitate the development of human IVS conditions. Testicular cells derived from hiPSCs are characterized for phenotype markers and profiled transcriptionally. HiPSC-derived testicular cells are bioprinted into core-shell constructs representative of testis cytoarchitecture and found to capture functional aspects of prepubertal testicular tissues within 7 days under xeno-free conditions. Moreover, hiPSC-derived Sertoli cells illustrate the capacity to mature under pubertal-like conditions. The utility of the model is tested by comparing 2 methods of supplementing retinoic acid (RA), the vitamin responsible for inducing spermatogenesis. The model reveals a significant gain in activity under microsphere-released RA compared to RA medium supplementation, indicating that the fragility of free RA in vitro may be a contributing factor to the molecular dysfunction observed in human IVS studies to date.
    Keywords:  bioprinting; human induced pluripotent stem cell; in vitro spermatogenesis; microsphere delivery; single cell RNA sequencing
    DOI:  https://doi.org/10.1002/adhm.202402606
  49. Cell Metab. 2025 Feb 11. pii: S1550-4131(25)00024-5. [Epub ahead of print]
    Ergothioneine controls mitochondrial function and exercise performance via direct activation of MPST.
    Hans-Georg Sprenger, Melanie J Mittenbühler, Yizhi Sun, Jonathan G Van Vranken, Sebastian Schindler, Abhilash Jayaraj, Sumeet A Khetarpal, Amanda L Smythers, Ariana Vargas-Castillo, Anna M Puszynska, Jessica B Spinelli, Andrea Armani, Tenzin Kunchok, Birgitta Ryback, Hyuk-Soo Seo, Kijun Song, Luke Sebastian, Coby O'Young, Chelsea Braithwaite, Sirano Dhe-Paganon, Nils Burger, Evanna L Mills, Steven P Gygi, Joao A Paulo, Haribabu Arthanari, Edward T Chouchani, David M Sabatini, Bruce M Spiegelman.
      Ergothioneine (EGT) is a diet-derived, atypical amino acid that accumulates to high levels in human tissues. Reduced EGT levels have been linked to age-related disorders, including neurodegenerative and cardiovascular diseases, while EGT supplementation is protective in a broad range of disease and aging models. Despite these promising data, the direct and physiologically relevant molecular target of EGT has remained elusive. Here, we use a systematic approach to identify how mitochondria remodel their metabolome in response to exercise training. From these data, we find that EGT accumulates in muscle mitochondria upon exercise training. Proteome-wide thermal stability studies identify 3-mercaptopyruvate sulfurtransferase (MPST) as a direct molecular target of EGT; EGT binds to and activates MPST, thereby boosting mitochondrial respiration and exercise training performance in mice. Together, these data identify the first physiologically relevant EGT target and establish the EGT-MPST axis as a molecular mechanism for regulating mitochondrial function and exercise performance.
    Keywords:  MPST; ergothioneine; exercise; mitochondria
    DOI:  https://doi.org/10.1016/j.cmet.2025.01.024
  50. J Biol Chem. 2025 Feb 13. pii: S0021-9258(25)00164-4. [Epub ahead of print] 108316
    Staufen2 dysregulation in neurodegenerative disease.
    Sharan Paul, Warunee Dansithong, Karla P Figueroa, Mandi Gandelman, Pravin Hivare, Daniel R Scoles, Stefan M Pulst.
      Staufen2 (STAU2) is an RNA binding protein that controls mRNA trafficking and expression. Previously, we showed that its paralog Staufen1 (STAU1) was overabundant in cellular and mouse models of neurodegenerative diseases and amyotrophic lateral sclerosis (ALS) patient spinal cord. Here we investigated features of STAU2 that might parallel STAU1. STAU2 protein, but not mRNA, was overabundant in spinocerebellar ataxia type 2 (SCA2), ALS/frontotemporal dementia (FTD) patient fibroblasts, ALS patient spinal cord tissues, and in central nervous system (CNS) tissues from SCA2 and ALS animal models. Exogenous expression of STAU2 in HEK293 cells activated mechanistic target of rapamycin (mTOR) and stress granule formation. Targeting STAU2 by RNAi normalized mTOR in SCA2 and C9ORF72 cellular models. The microRNA miR-217, previously identified as downregulated in SCA2 mice, targets the STAU2 3'-UTR. We now demonstrate that exogenous expression of miR-217 significantly reduced STAU2 and mTOR levels in cellular models of neurodegenerative disease. These results suggest a functional link between STAU2 and mTOR signaling and identify a major role for miR-217 that could be exploited in therapeutic development.
    DOI:  https://doi.org/10.1016/j.jbc.2025.108316
  51. Mol Neurodegener. 2025 Feb 21. 20(1): 21
    Mechanisms of astrocyte aging in reactivity and disease.
    Holly K Gildea, Shane A Liddelow.
      Normal aging alters brain functions and phenotypes. However, it is not well understood how astrocytes are impacted by aging, nor how they contribute to neuronal dysfunction and disease risk as organisms age. Here, we examine the transcriptional, cell biology, and functional differences in astrocytes across normal aging. Astrocytes at baseline are heterogenous, responsive to their environments, and critical regulators of brain microenvironments and neuronal function. With increasing age, astrocytes adopt different immune-related and senescence-associated states, which relate to organelle dysfunction and loss of homeostasis maintenance, both cell autonomously and non-cell autonomously. These perturbed states are increasingly associated with age-related dysfunction and the onset of neurodegeneration, suggesting that astrocyte aging is a compelling target for future manipulation in the prevention of disease.
    Keywords:  Aging; Astrocyte; Astrocyte reactivity; Glia; Inflammaging; Lipid droplets; Mitochondria; Neurodegenerative disease; Proteostasis; Senescence
    DOI:  https://doi.org/10.1186/s13024-025-00810-7
  52. Methods Mol Biol. 2025 Feb 19.
    Generation of Functional Brain Region-Specific Neural Spheroids for High Throughput Screening.
    Jiajing Zhang, Angelica Medina, Marc Ferrer, Emily M Lee.
      Therapeutic development and research in the neurodegenerative disease field encounters many challenges such as availability of reproducible and scalable cellular model systems that are biologically, physiologically, and pharmacologically relevant. These cellular models must be informative of cellular mechanisms of diseases and predictive for therapeutics efficacy and toxicity testing during drug discovery and development. Neural spheroids fill the gap of cellular models of the brain that are functional, versatile in neural cell type composition, robust, and scalable for high-throughput screening (HTS). We have previously developed a protocol to aggregate pre-determined ratios of differentiated human-induced pluripotent stem cell (hiPSC)-derived neurons and astrocytes in a scaffold-free environment to form 3D brain-region specific spheroids. By mixing different neuronal types, neural spheroids can be used to simulate the neuronal-type heterogeneity of distinct brain regions in vivo, including the prefrontal cortex (PFC) and ventral tegmental area (VTA). Here, we present a detailed description of a method for generating functional brain region-specific spheroids with HTS-compatible assay readout that monitors changes in neural network activity by measuring calcium oscillations. The versatility of the platform is such that these neural spheroids cellular assays are applicable for a wide range of disease modeling, compound validation, and screening and are limited only by the availability of input cells, including neural subtype, disease cells, and immune cells such as microglia.
    Keywords:  Brain-region like; Calcium oscillations; Disease modeling; Drug discovery; Functional readouts; High-throughput screening; Human-induced pluripotent stem cell differentiated brain cells; Neural spheroids; Three-dimensional culture
    DOI:  https://doi.org/10.1007/7651_2024_593
  53. Autophagy. 2025 Feb 19.
    Lysosomal Quality Control.
    Danielle Henn, Xi Yang, Ming Li.
      Healthy cells need functional lysosomes to degrade cargo delivered by autophagy and endocytosis. Defective lysosomes can lead to severe conditions such as lysosomal storage diseases (LSDs) and neurodegeneration. To maintain lysosome integrity and functionality, cells have evolved multiple quality control pathways corresponding to different types of stress and damage. These can be divided into five levels: regulation, reformation, repair, removal, and replacement. The different levels of lysosome quality control often work together to maintain the integrity of the lysosomal network. This review summarizes the different quality control pathways and discusses the less-studied area of lysosome membrane protein regulation and degradation, highlighting key unanswered questions in the field.
    Keywords:  ESCRT; Lysophagy; lysosome membrane protein regulation; lysosome membrane repair; lysosome quality control
    DOI:  https://doi.org/10.1080/15548627.2025.2469206
  54. Eur J Pharm Biopharm. 2025 Feb 13. pii: S0939-6411(25)00041-4. [Epub ahead of print] 114665
    Mannose-6-phosphate-PEG-lipid conjugates improve liposomal uptake.
    Boris Sevarika, Deniz Capri, Joël Frey, Margarita C Dinamarca, Daniel Häussinger, Scott McNeil.
      Targeted liposomes are a keystone of nanomedicine, offering a precise and efficient means to deliver therapeutic agents directly to diseased tissues or cells. By incorporating targeting ligands on their surface, liposomes enhance the specificity of drug delivery, improving efficacy and reducing toxicity. Mannose-6-phosphate (M6P) is a crucial molecular tag for internalization and intracellular sorting of macromolecular structures to lysosomes. Taking advantage of this mechanism, we designed and developed liposomal systems to enhance therapeutic delivery to the lysosomes. The synthesized M6P-based targeting molecules were covalently coupled to a phospholipid using a polyethylene glycol (PEG) linker. The prepared ligands were successfully incorporated into the liposomes, yielding a size of roughly 100 nm and a zeta potential of around -40 mV. Incorporating the M6P-based ligand enhances the internalization of liposomes in a concentration-dependent manner, increasing uptake by up to 14-fold in several tested cell lines. In contrast, structurally similar monosaccharides and equally charged ligands failed to replicate this effect, highlighting the specificity of M6P-mediated internalization. Our studies demonstrate that M6P-mediated uptake predominantly occurs via a clathrin-mediated pathway, and once internalized, 72 % of the M6P-coated liposomes are associated with the lysosomal compartment. This study highlights the potential of M6P-based liposomal carriers as a modular platform for targeted lysosomal delivery, offering a promising therapeutic approach for lysosomal storage diseases.
    Keywords:  Enzyme replacement therapy; Liposomes; Lysosomal storage diseases; Lysosomal targeting; Mannose-6-phosphate
    DOI:  https://doi.org/10.1016/j.ejpb.2025.114665
This page is being maintained by Thomas Krichel. It was last updated on 2025‒02‒24 at 13:53.