bims-axbals 2026-02-15 papers

bims-axbals

Biomed News

on Axonal biology and ALS

Issue of 2026–02–15
35 papers selected by
TJ Krzystek

From Dish to Trial: Building Translational Models of ALS.
Pathological TDP-43 filaments accumulate at synapses and cause synaptic dysfunction.
Golgi fragmentation driven by the USP11-ITCH axis triggers autolysosomal failure in neurodegeneration.
MicroRNA profiling in post-mortem spinal cord of C9ORF72-related ALS patients reveals molecular pathways involved in motor neuron degeneration.
Lost in translation: absence of KIAA1324/ELAPOR1 protein in pathological TDP-43-affected neurons in ALS/FTD.
Transplantation of Human IPSC-derived Microglia Ameliorates Neuropathology and Circuit Dysfunction in Progranulin-Deficient Mice.
TDP-43 Mediates Autophagic Degradation of Yki by Stabilizing Ref(2)P in Drosophila.
From Evasion to Collapse: The Kinetic Cascade of TDP-43 and the Failure of Proteostasis.
Cell-Internal Nanomagnetic Forces Alter Cytoskeletal Protein Transport Dynamics in Developing Excitatory Axons.
Structural and biochemical basis of ROC-dependent activation of LRRK2.
Behavioral Variant Frontotemporal Dementia With C9orf72 Intermediate Repeat Expansion: A case report.
Extracellular vesicles at the neuromuscular junction: messengers of synaptic health and disease.
A neuron type-specific microexon in Ank3/ankyrin-G modulates calcium activity and neuronal excitability.
Unraveling the core: hub genes bridging familial and sporadic Parkinson's disease.
Divergent mitochondrial and metabolic adaptations shape selective vulnerability in ALS.
Mitochondria and Lipid Defects in Hereditary Progranulin-Related Frontotemporal Dementia.
VMAT2 dysfunction impairs vesicular dopamine uptake, driving its oxidation and α-synuclein pathology in DJ-1-linked Parkinson's neurons.
A HaloTag-4R-Tau Pulse-Chase Sensor Reveals Neddylation Inhibition Promotes Degradation of Tau in iNeurons.
Genetic regulators of neuronal survival across metabolic environments.
Calcium and magnesium deficiency induces stress granule formation to maintain magnesium homeostasis.
Leucettinib-21 decreases dosage effects of DYRK1A in human trisomy 21 iPSC-derived neural cells.
Old enough to be a model? On the role of maturity in stem cell-based models for neuropsychiatric disorders.
High Content In Vitro Survival Assay of Cortical Neurons.
Impact of G-quadruplex RNA oxidation on its conformational dynamics and interaction with ALS-associated TDP-43.
Tributyltin induces conjugation of ATG8s to single membranes via the V-ATPase-ATG16L1 axis, leading to transcription factor EB activation in human cell lines.
Current Advances and Applications of Retinal Organoids.
Spatiotemporal regulation of endocytic membrane trafficking by voltage-sensing phosphatase (VSP) in zebrafish enterocytes.
Use-dependent regulation of the axonal action potential in parvalbumin-expressing interneurons.
Parkinson's Disease Patient-Specific Striatum Organoids Show Hallmarks of Increased Inflammation.
Exploiting NMR Ensemble Heterogeneity Enables Small Molecule Discovery Against Dynamic Protein-Protein Interfaces.
The cytoskeleton regulates cytoophidium dynamics in Drosophila ovaries.
Lymphoid Organ Architecture and Hematopoiesis Disruption in Spinal Muscular Atrophy: Therapeutic Rescue by SMN Restoration.
Identification and characterization of the functional LolB ortholog in Bacteroides.
Teravoxel Microscopy Image Analysis for Neurological Diseases.
Distinct neuronal alterations distinguish two subtypes of sporadic Creutzfeldt-Jakob disease with shared dysfunctional pathways.

Cells. 2026 Jan 27. pii: 247. [Epub ahead of print]15(3):

From Dish to Trial: Building Translational Models of ALS.

Ilias Salamotas, Sotiria Stavropoulou De Lorenzo, Aggeliki Stachtiari, Apostolos Taxiarchis, Magda Tsolaki, Iliana Michailidou, Elisavet Preza.

  Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease, marked by progressive degeneration of upper and lower motor neurons. Clinically, genetically, and pathologically heterogeneous, ALS poses a major challenge for disease modeling and therapeutic translation. Over the past two decades, induced pluripotent stem cells (iPSCs) have reshaped our understanding of ALS pathogenesis and emerged as a promising translational platform for therapy development. ALS modeling has further expanded with the advent of three-dimensional systems, including ALS-on-chip platforms and organoid models, which better capture cell-cell interactions and tissue-level phenotypes. Despite these advances, effective disease-modifying therapies remain elusive. Recent clinical trial setbacks highlight the need for improved trial design alongside robust, translational iPSC models that can better predict therapeutic response. Nonetheless, the outlook is promising as large iPSC patient cohorts, quantitative phenotyping combined with genetically informed patient stratification, and reverse translational research are beginning to close the gap between in vitro discovery and clinical testing. In this review, we summarize the major advances in iPSC technology and highlight key iPSC-based studies of sporadic ALS. We further discuss emerging examples of iPSC-informed therapeutic strategies and outline the challenges associated with translating iPSC-derived mechanistic insights and pharmacological findings into successful clinical therapies.

Keywords:  NMJ; clinical trials; iPSC; organoids; preclinical models; sporadic ALS; therapeutic strategies

DOI:  https://doi.org/10.3390/cells15030247
bioRxiv. 2026 Jan 27. pii: 2026.01.27.701787. [Epub ahead of print]

Pathological TDP-43 filaments accumulate at synapses and cause synaptic dysfunction.

Renren Chen, Imogen Stockwell, Jessica C Pierce, Sew-Yeu Peak-Chew, Melissa Huang, Kathy Newell, Bernardino Ghetti, Michael A Cousin, Ingo H Greger, Benjamin Ryskeldi-Falcon.

The assembly of TAR DNA-binding protein 43 (TDP-43) into amyloid filaments within neurons is a hallmark of multiple neurodegenerative diseases, including motor neuron diseases (MND), frontotemporal dementias (FTD) and limbic-predominant age-related TDP-43 encephalopathy (LATE). These diseases result from the deterioration and loss of neurons, with synaptic dysfunction and neuronal hyperexcitability being prominent early events. Pathogenic mutations in the TDP-43 gene, TARDBP , that promote filament formation have established a causal role for TDP-43 assembly in neurodegenerative diseases. However, the molecular mechanisms underlying filament accumulation and their contribution to neurodegeneration are poorly understood. TDP-43 filaments can propagate between neurons in a prion-like manner, which may underlie the progressive spread and accumulation of TDP-43 pathology in disease. Here, we studied early stages of TDP-43 filament accumulation following internalisation of patient-derived TDP-43 filaments by mouse and human cortical neurons. Using proximity labelling, we identified molecular environments and putative interactions of TDP-43 filaments. We found that TDP-43 filaments accumulated at synapses, particularly in proximity to the presynaptic active zone, which we confirmed in FTD patient brain sections. Electron cryo-tomography (cryo-ET) directly visualised abundant TDP-43 filaments spanning the presynaptic cytoplasm in situ , which contacted synaptic vesicles and the plasma membrane. Functional measurements revealed that the accumulation of TDP-43 filaments led to presynaptic dysfunction and subsequent neuronal hyperexcitability. These findings suggest that synapses are a major early site of TDP-43 filament accumulation, relevant to their propagation, and directly link TDP-43 filament gain of function to synaptic dysfunction.

DOI: https://doi.org/10.64898/2026.01.27.701787
Autophagy. 2026 Feb 10. 1-2

Golgi fragmentation driven by the USP11-ITCH axis triggers autolysosomal failure in neurodegeneration.

Qiwang Xiang, Yang Liu, Jiou Wang.

  Golgi fragmentation is a prominent early hallmark of neurodegenerative diseases such as Alzheimer disease (AD) and amyotrophic lateral sclerosis (ALS), yet the shared molecular mechanisms underlying this phenomenon remain poorly understood. Here we identify the E3 ubiquitin ligase ITCH as a central regulator of Golgi integrity and proteostasis. Elevated ITCH disrupts both cis- and trans-Golgi networks, dislocates lysosomal hydrolase sorting factors, and impairs maturation of hydrolases. The ensuing lysosomal dysfunction leads to autophagosome accumulation and defective clearance of accumulated cytoplasmic toxic proteins like TARDBP/TDP-43. Genetic and pharmacological inhibition of ITCH restores autolysosomal degradation and protects neurons in both mammalian and Drosophila models. Aberrant buildup of the deubiquitinase USP11 drives ITCH accumulation, intensifying neuronal proteotoxic stress in individuals with AD and ALS. These findings reveal a mechanistic pathway connecting Golgi disorganization, autolysosomal impairment, and proteotoxic stress in neurodegeneration.

Keywords:  Autophagy; Golgi fragmentation; ITCH; USP11; lysosome; neurodegenerative diseases

DOI:  https://doi.org/10.1080/15548627.2026.2629295
Front Neurosci. 2026 ;20 1741065

MicroRNA profiling in post-mortem spinal cord of C9ORF72-related ALS patients reveals molecular pathways involved in motor neuron degeneration.

Giorgia Farinazzo, Eleonora Giagnorio, Matteo Marcuzzo, Marco Cattaneo, Claudia Malacarne, Paola Cavalcante, Silvia Bonanno, Emanuela Maderna, Viviana Pensato, Cinzia Gellera, Gianluca Marucci, Samanta Mazzetti, Erika Salvi, Giuseppe Lauria, Stefania Marcuzzo.

   Introduction: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder causing progressive motor neuron death in cortex, brainstem and spinal cord. The most common genetic cause is the G4C2 hexanucleotide repeat expansion in the non-coding region of exon 1 of C9ORF72, accounting for ~40% of familial and ~7% of sporadic ALS. RNA dysregulation is increasingly recognized as a key contributor to ALS pathogenesis. This study aimed to identify specific microRNAs (miRNAs) involved in motor neuron degeneration in C9ORF72-ALS.
Methods: We profiled 754 miRNAs in human post-mortem spinal cord tissue from C9ORF72-ALS patients and healthy donors. Laser capture microdissection isolated ventral horn regions, and in silico target prediction identified potential genes and pathways regulated by differentially expressed miRNAs. Target genes were validated by Real time PCR.
Results: Two subsets of miRNAs were exclusively expressed in ventral horn regions: miR-200b-3p and miR-346 in C9ORF72-ALS patients, and miR-30d-5p, miR-106b-5p and miR-135a-5p in healthy donors. Target prediction and molecular analysis identified putative genes and pathways linked to cell death, inflammation, protein metabolism, DNA modification, excitotoxicity, autophagy and vesicles trafficking.
Discussion: This study identifies specific miRNAs and their target genes as key molecules in motor neuron degeneration in C9ORF72-ALS. Restoring their expression could represent a therapeutic approach for ALS.

Keywords:  C9ORF72-amyotrophic lateral sclerosis; human post-mortem spinal cord tissue; microRNAs; motor neuron; target genes

DOI:  https://doi.org/10.3389/fnins.2026.1741065
Acta Neuropathol Commun. 2026 Feb 10.

Lost in translation: absence of KIAA1324/ELAPOR1 protein in pathological TDP-43-affected neurons in ALS/FTD.

Maize C Cao, Molly E V Swanson, Indranil Basak, Kirstin McDonald, Frederick J Arnold, Cameron M Stockford, George Guo, Maurice A Curtis, Richard L M Faull, Stephanie M Hughes, Albert R La Spada, Michael Dragunow, Emma L Scotter.

   BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a movement disorder lacking effective diagnostics and therapeutics, largely due to its clinical and etiological heterogeneity. The unifying hallmark of TDP-43 pathology is found in approximately 97% of ALS patients, and 50% of frontotemporal dementia (FTD) patients. Indeed, TDP-43 has a central role in ALS/FTD disease mechanisms. An mRNA target of TDP-43 loss of function, KIAA1324/ELAPOR1, is consistently upregulated in various RNA-sequencing datasets from systems with TDP-43 depletion.
METHODS: This study sought to investigate the TDP-43 target gene, KIAA1324, in the context of human brain tissue. We performed immunohistochemistry and image analysis on 10 ALS and 10 control brains to quantify the protein levels of KIAA1324 in TDP-43 pathology-affected cells. We then used immunocytochemistry of iPSC-derived neurons and mass spectroscopy of SH-SY5Y cells to investigate the relationship between KIAA1324 mRNA and the function of its cognate protein KIAA1324.
RESULTS: KIAA1324 expression was enriched in neurons in the human brain. While KIAA1324 mRNA increased in iPSC-derived neurons with TDP-43 depleted from the nucleus in vitro, in human post-mortem brain neurons, KIAA1324 protein was significantly decreased (p < 0.05) in cells with pathological TDP-43 (nuclear-cleared TDP-43 and cytoplasmic, phosphorylated TDP-43). This may be due to the alternative polyadenylation of KIAA1324 detected with TDP-43 depletion from iPSC-derived neurons, hypothesised to affect translation efficiency. Mass spectrometry of SH-SY5Y cells revealed that overexpression of KIAA1324 protein affects a network of mitochondrial proteins.
CONCLUSIONS: The clear inverse relationship between KIAA1324 mRNA levels and TDP-43 function, and the near complete absence of KIAA1324 protein from neurons with pathological TDP-43 in post-mortem brain tissue, suggests KIAA3142 function is impaired in TDP-43 proteinopathies. Therefore, in addition to there being various disease mechanisms implicated in ALS, and TDP-43 being a challenging disease target to restore, KIAA1324 emerges as another of the many targets downstream of TDP-43 that may need to be addressed to demonstrate a therapeutic effect in ALS/FTD.

Keywords:  Alternative polyadenylation; Amyotrophic lateral sclerosis; EIG121; ELAPOR1; Frontotemporal dementia; Human brain immunohistochemistry; KIAA1324; Motor neuron disease; Neuron; TDP-43

DOI:  https://doi.org/10.1186/s40478-026-02237-7
Res Sq. 2026 Feb 03. pii: rs.3.rs-8603227. [Epub ahead of print]

Transplantation of Human IPSC-derived Microglia Ameliorates Neuropathology and Circuit Dysfunction in Progranulin-Deficient Mice.

Hayk Davtyan, Sarah Naguib, Yuliya Voskobiynyk, Jean Paul Chadarevian, Joia K Capocchi, Jeannie L Giacchino, Ghazaleh Eskandari-Sedighi, Vivianna DeNittis, Jeremy B Ford, Ani Agababian, Jasmine Nguyen, Alina L Chadarevian, Madison S Sutherland, Sepideh Kiani Shabestari, Alissa L Nana, Jiasheng Zhang, Salvatore Spina, Man Ying Wong, Lea T Grinberg, William W Seeley, Eric Huang, Claire D Clelland, Shiaoching Gong, Li Fan, Jeanne T Paz, Mathew Blurton-Jones, Li Gan.

Frontotemporal dementia (FTD) is a major cause of early-onset neurodegeneration characterized by progressive behavioral, emotional, and cognitive decline. Progranulin haploinsufficiency, a leading genetic cause of familial FTD, disrupts lysosomal function, lipid metabolism, autophagy, and neuroimmune signaling across multiple cell types. Increasing evidence indicates that microglia are particularly sensitive to progranulin loss, exhibiting elevated complement activation that contributes to TDP-43 proteinopathy and neuronal dysfunction. Here, we investigate the biological role of restoring progranulin exclusively within microglia by transplanting human induced pluripotent stem cell-derived microglia (iMG) into progranulin ( Grn )-deficient mice. We find that wild-type, but not Grn -deficient, human iMG restore brain-wide progranulin levels, normalize microglial transcriptional states, and ameliorate pathological, functional, and behavioral phenotypes associated with progranulin loss. Because microglia are the only source of progranulin in this system, these findings demonstrate that microglial progranulin is sufficient to restore key aspects of cellular, circuit, and behavioral homeostasis in a progranulin-deficient FTD model. More broadly, this work highlights a central, microglia-intrinsic role for progranulin in maintaining brain function and provides a framework for dissecting microglia-specific mechanisms across FTD and related neurodegenerative disorders.

DOI: https://doi.org/10.21203/rs.3.rs-8603227/v1
FASEB J. 2026 Feb 28. 40(4): e71572

TDP-43 Mediates Autophagic Degradation of Yki by Stabilizing Ref(2)P in Drosophila.

Dongyue Liu, Yufang Xu, Haochuan Wang, Shuai Huang, Shuangxi Li.

  The transcriptional co-activator Yki, the central effector of the Hippo signaling pathway, plays essential roles in regulating tissue growth, regeneration, and tumorigenesis. Although upstream signaling mechanisms controlling Yki activity have been extensively characterized, the molecular mechanisms that govern Yki protein homeostasis remain incompletely understood. In this study, we identify TAR DNA-binding protein 43 (TDP-43) as a critical regulator of Yki proteostasis and demonstrate that stabilization of the autophagic receptor Ref(2)P is indispensable for TDP-43-mediated Yki turnover. Our findings reveal that TDP-43 elevates Ref(2)P levels through two distinct mechanisms. At the post-translational level in the cytoplasm, TDP-43 disrupts the interaction between Ref(2)P and the kinase Dco, thereby preventing phosphorylation-dependent proteasomal degradation of Ref(2)P. At the post-transcriptional level in the nucleus, TDP-43 promotes Ref(2)P mRNA stability by interacting with the nuclear m6A reader protein Ythdc1, which facilitates recognition of N6-methyladenosine (m6A)-modified Ref(2)P transcripts and protects them from decay. Together, these findings delineate a dual regulatory mechanism by which TDP-43 controls Ref(2)P abundance and Yki proteostasis, providing new insights into the fine-tuning of Hippo pathway activity.

Keywords:   Drosophila melanogaster ; Ref(2)P; TDP‐43; Yki

DOI:  https://doi.org/10.1096/fj.202503852RR
Int J Mol Sci. 2026 Jan 23. pii: 1136. [Epub ahead of print]27(3):

From Evasion to Collapse: The Kinetic Cascade of TDP-43 and the Failure of Proteostasis.

Angelo Jamerlan, John Hulme.

  Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are devastating neurodegenerative diseases that, despite the availability of symptomatic and modestly beneficial treatments, still lack therapies capable of halting disease progression. A histopathological hallmark of both diseases is the cytoplasmic deposition of TDP-43 in neurons, which is attributed to both intrinsic (e.g., mutations, aberrant cleavage) and extrinsic factors (e.g., prolonged oxidative stress, impaired clearance pathways). Mutations and certain PTMs (e.g., cysteine oxidation) destabilize RNA binding, promoting monomer misfolding and increasing its half-life. Disruptions to core ubiquitin-proteasome system (UPS) subunits impede efficient processing, contributing to the clearance failure of misfolded TDP-43 monomers. The accumulation of monomers drives phase separation within stress granules, creating nucleation hotspots that eventually bypass the thermodynamic barrier, resulting in exponential growth. This rapid growth then culminates in the failure of the autophagy-lysosome pathway (ALP) to contain the aggregation, resulting in a self-sustaining feed-forward loop. Here, we organize these factors into a conceptual kinetic cascade that links TDP-43 misfolding, phase separation, and clearance failure. Therapeutic strategies must therefore move beyond simple clearance and focus on targeting these kinetic inflection points (e.g., oligomer seeding, PTM modulation).

Keywords:  TDP-43 proteinopathy; amyotrophic lateral sclerosis (ALS); autophagy-lysosome pathway (ALP); frontotemporal dementia (FTD); neurodegeneration; phase separation; post-translational modifications (PTMs); proteostasis collapse; ubiquitin-proteasome system (UPS)

DOI:  https://doi.org/10.3390/ijms27031136
Nano Lett. 2026 Feb 10.

Cell-Internal Nanomagnetic Forces Alter Cytoskeletal Protein Transport Dynamics in Developing Excitatory Axons.

Mackenna K Landis, Anja Kunze.

  Cytoskeletal proteins such as F-Actin and Microtubules are critical to the growth, morphology, and function of neurons. These proteins provide active force to enable the outgrowth and structural maintenance of the axon. Therefore, manipulation of these proteins could enable more specific engineering of axonal outgrowth. Previous works have utilized magnetically actuated mechanical forces to alter the axonal distribution of these proteins and manipulate in vitro movement. However, the impacts of exogenous forces on critical cytoskeletal protein transport dynamics within live axons have not yet been examined. In this study, we build on our previous work to examine the impacts of cell-internal nanomagnetic forces on the transport of human β-Actin and Tubulins. We identified differential magnetic nanoparticle uptake in cortical neurons at two stages of development. During the earlier developmental stage, anterograde-aligned forces actuated by these particles could bias α-Tubulin transport. Influencing axonal protein transport could enable targeted neural engineering in the future.

Keywords:  Actin and tubulin dynamics; Cytoskeletal protein transport; Excitatory and inhibitory neurons; Magnetic nanoparticle actuation; Neural engineering

DOI:  https://doi.org/10.1021/acs.nanolett.5c05742
Res Sq. 2026 Feb 02. pii: rs.3.rs-8735353. [Epub ahead of print]

Structural and biochemical basis of ROC-dependent activation of LRRK2.

Quyen Hoang, Yangshin Park, Chunxiang Wu, Kayla Tennessen, Li Wan, Neo Hoang, Cardea Hoang, Jingling Liao.

Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common cause of familial Parkinson's disease, yet the molecular mechanism governing LRRK2 activation remains incompletely understood. LRRK2 is a large multidomain enzyme whose kinase activity is regulated by intramolecular interactions and by its Ras of complex proteins (ROC) GTPase domain. Here, we combine cryo-electron microscopy, X-ray crystallography, and structure-guided biochemical perturbations to define how ROC conformational switching regulates LRRK2 activation. Cryo-EM reconstructions reveal that monomeric full-length LRRK2 samples three distinct conformational states-autoinhibited, intermediate, and activated-indicating that large-scale activation-associated rearrangements can occur through an intrinsic intramolecular pathway, independently of Rab29 binding, higher-order oligomerization, or membrane association. A 1.6 Å crystal structure of an extended ROC construct reveals intrinsic conformational plasticity within the GTPase switch regions that likely underlies these transitions. Structure-guided disulfide engineering identifies a functional coupling between residue R1441 and Switch II that directly modulates GTPase activity in both isolated ROC and full-length LRRK2. Disruption of this coupling phenocopies the disease-associated R1441H mutation. Together, these findings establish ROC as a dynamic conformational engine that drives a multistep intramolecular activation mechanism in LRRK2, providing mechanistic insight into how pathogenic mutations promote aberrant kinase activation.

DOI: https://doi.org/10.21203/rs.3.rs-8735353/v1
Alzheimer Dis Assoc Disord. 2026 Feb 10.

Behavioral Variant Frontotemporal Dementia With C9orf72 Intermediate Repeat Expansion: A case report.

Sufen Huang, Yuzhang Bei, Qingxiang Zhang, Haitian Nan, Junjie Li.

  Hexanucleotide repeat expansion in the chromosome 9 open reading frame 72 (C9orf72) gene has been identified as the most common genetic cause of both frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). While large pathogenic expansions can reach hundreds to thousands of repeats, the lower limit for the number of pathogenic repeats remains controversial. Pathogenic threshold ranges from 30 to >60 repeats. Here, we report a rare case of behavioral variant frontotemporal dementia (bvFTD) associated with a C9orf72 repeat expansion of 49 units, a size that falls within the intermediate-length range. The patient presented with progressive neuropsychiatric decline, which progressed to include emotional blunting and memory impairment. Neuroimaging demonstrated bilateral temporal and hippocampal atrophy, with a reduction in glucose metabolism observed in the left fronto-parieto-temporal cortex and thalamus. This study may provide crucial clinical evidence for the ongoing debate on the pathogenicity of intermediate-length alleles in C9orf72.

Keywords:  ; behavioral variant dementia; case report; frontotemporal dementia; intermediate; repeat expansion

DOI:  https://doi.org/10.1097/WAD.0000000000000718
Cell Tissue Res. 2026 Feb 13. 403(2): 20

Extracellular vesicles at the neuromuscular junction: messengers of synaptic health and disease.

Rizwan Qaisar.

  Extracellular vesicles (EVs) have emerged as pivotal modulators of neuromuscular junction (NMJ) biology, reshaping our understanding of synaptic communication, maintenance, and degeneration. This review consolidates current insights into the roles of EVs derived from motor neurons, muscle fibers, and Schwann cells in regulating NMJ integrity. In healthy states, EVs deliver trophic factors, structural proteins, and regulatory RNAs that promote the clustering of acetylcholine receptors, presynaptic stability, and axonal growth. Motor neuron EVs carry Wnt7a, synaptophysin, and PGC-1α, while muscle-derived EVs deliver miR-206, agrin, and caveolin-3. Schwann cell EVs contribute neurotrophic support via NRG1 and GDNF. In contrast, diseased or aged NMJs exhibit EV cargo dysregulation, marked by the presence of misfolded proteins (e.g., SOD1, TDP-43), pro-inflammatory cytokines, and reduced regenerative miRNAs. These changes contribute to synaptic dismantling, neuroinflammation, and impaired repair in conditions such as ALS, SMA, MG, and sarcopenia. The review highlights the bidirectional nature of EV signalling and its dynamic regulation by neuronal activity and stress. Emerging therapeutic strategies include engineering EVs to deliver protective cargo, targeting them to NMJ components, and designing biomaterial-based depots for sustained release. Furthermore, EV signatures in blood and muscle hold promise as non-invasive biomarkers for early detection of NMJ decline in ALS, SMA, MG, and sarcopenia. Despite promising preclinical data, challenges remain in EV characterization, targeting specificity, and clinical translation. This review underscores a paradigm shift: EVs are not passive byproducts but active messengers of neuromuscular health and disease, with realistic applications in diagnostics, regenerative therapy, and personalized medicine.

Keywords:  EV-based therapeutics; Extracellular vesicles; Motor neuron disease; Neuromuscular junction; Sarcopenia

DOI:  https://doi.org/10.1007/s00441-026-04050-z
Nat Commun. 2026 Feb 13.

A neuron type-specific microexon in Ank3/ankyrin-G modulates calcium activity and neuronal excitability.

Shah Alam, Georgia Dermentzaki, David Cabrera-Garcia, Miao Li, Ruizhi Wang, Melissa Campbell, Ilaria Balbo, Brittany L Phillips, Min Li, Jessica Estrada, Marianna Zazhytska, Yow-Tyng Yeh, Lia Min, Elizabeth Rafikian, Elizabeth Valenzuela, Brian Joseph, Tulsi Patel, Dmytro Ustianenko, Helene Lovett, Huijuan Feng, Xiaojian Wang, Susan Brenner-Morton, Chyuan-Sheng Lin, Clarissa L Waites, Hynek Wichterle, Lizhen Chen, Mu Yang, Edmund Au, Marko Jovanovic, Stavros Lomvardas, Paul M Jenkins, Rui Yang, Sheng-Han Kuo, Yueqing Peng, Guang Yang, Neil L Harrison, Chaolin Zhang.

Recent studies have revealed many alternative exons differentially spliced across diverse neuron types in the mammalian brain, but their links to neuronal physiology remain unclear. Here we characterize a deeply conserved microexon E35a in Ank3 encoding ankyrin-G (AnkG), a multifaceted adaptor protein best known as a master organizer of the axon initial segment (AIS) and as a leading genetic risk factor for bipolar disorder. E35a is predominantly skipped in cortical glutamatergic neurons but included in cortical GABAergic neurons and cerebellar neurons, which is dictated by multiple neuronal splicing factors. In E35a-deletion mice we generated, interneurons show increased excitability and somatic Ca2+ activity, without disruption in AIS. Biochemical analyses suggest that E35a inclusion facilitates AnkG interaction with a protein complex involving inositol trisphosphate receptors (InsP3Rs) important for intracellular Ca2+ signaling. Alternative splicing therefore allows AnkG to modulate neuron type-specific excitability in addition to its ubiquitous pan-neuronal role in organizing the AIS.

DOI: https://doi.org/10.1038/s41467-026-69486-x
J Neurol. 2026 Feb 11. 273(2): 135

Unraveling the core: hub genes bridging familial and sporadic Parkinson's disease.

Simran Singh, Gulshan Chauhan, Baisakhi Moharana, Sonia Verma.

  Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the selective loss of dopaminergic (DA) neurons in the substantia nigra. Although familial and sporadic forms of PD have distinct etiological origins, they converge on overlapping molecular pathways that remain incompletely understood. In this study, we aimed to identify shared "hub genes" that may drive DA neuron degeneration across both PD subtypes. We reanalyzed gene expression profiles from three publicly available datasets comprising DA neuron samples derived from postmortem human midbrains and patient-induced pluripotent stem cell-derived DA neurons. Twelve hub genes were consistently dysregulated across all datasets. Functional annotation revealed that these genes are critically involved in membrane trafficking and vesicle-mediated transport-key processes for maintaining neuronal integrity and synaptic function. Network-based analysis further linked these hub genes to a range of other neurological and systemic disorders, indicating broader relevance to disease biology. Experimental validation in neurotoxin-exposed SH-SY5Y cell models of PD confirmed significant dysregulation of several candidate genes at both mRNA and protein levels. Moreover, RNAi-mediated silencing of a key hub gene in Caenorhabditis elegans led to enhanced DA neuron degeneration, reinforcing its functional role in neuronal survival. Together, these findings identify a set of conserved molecular drivers of DA neuron vulnerability and propose novel therapeutic targets for both familial and sporadic PD.

Keywords:  Dopaminergic Neurons; Familial Parkinson's disease; Hub genes; Neurodegeneration; Novel Therapeutic Targets; Sporadic Parkinson's disease

DOI:  https://doi.org/10.1007/s00415-025-13429-x
bioRxiv. 2026 Feb 02. pii: 2026.01.30.702552. [Epub ahead of print]

Divergent mitochondrial and metabolic adaptations shape selective vulnerability in ALS.

Bianca A Cotto, Lizi Zhang, Benjamin Fait, Chris Peralta, Ece Kilic, Henrik Molina, Nathaniel Heintz, Eric F Schmidt.

Neurodegenerative diseases like amyotrophic lateral sclerosis (ALS) exhibit striking cell-type selectivity, yet the basis for this vulnerability remains elusive. Here, we uncover that even closely related neurons can harbor distinct mitochondrial properties that shape their response to disease. Using TOM-Tag, a circuit-based AAV-based strategy for cell type-specific mitochondrial immunopurification from projection neurons, we performed integrative proteomic, metabolomic, transcriptomic, and functional analyses of mitochondria from ALS-vulnerable corticospinal projection neurons (CSPNs) and resilient corticothalamic projection neurons (CTPNs) in vivo. We discovered that CSPNs and CTPNs exhibit divergent mitochondrial profiles at baseline, despite sharing cortical layer and developmental origin. CTPNs were primed for antioxidant buffering and fatty acid metabolism, whereas CSPNs were enriched for oxidative phosphorylation components. In ALS, CTPNs employed mitochondrial flexibility and redox defense, whereas CSPNs exhibited respiratory failure and metabolic stress. These findings reveal that intrinsic mitochondrial programs vary even between similar neurons, and that this hidden layer of diversity may critically shape susceptibility to neurodegeneration. By enabling high-resolution access to mitochondria in defined neuronal circuits, TOM-Tag offers a powerful new lens for dissecting disease mechanisms and identifying cell-specific therapeutic targets.

DOI: https://doi.org/10.64898/2026.01.30.702552
Cells. 2026 Feb 01. pii: 276. [Epub ahead of print]15(3):

Mitochondria and Lipid Defects in Hereditary Progranulin-Related Frontotemporal Dementia.

Jon Ondaro, Jose Luis Zúñiga-Elizari, Mónica Zufiría, Maddi Garciandia-Arcelus, Ángela Sánchez Molleda, Miren Zulaica, Miguel Lafarga, Javier Riancho, Adolfo López de Munaín, Fermin Moreno, Francisco Javier Gil-Bea, Gorka Gerenu.

  Frontotemporal dementia (FTD) is a neurodegenerative disorder predominantly affecting individuals under 65 years of age, characterized by significant behavioral and language disabilities. Despite extensive research efforts, effective treatments for FTD remain elusive. Familial cases of FTD have been linked to genetic mutations in several key genes, among these, mutations in granulin (GRN) account for 5-20% of cases, leading to haploinsufficiency of progranulin (PGRN), a multifunctional glycoprotein. This study investigates the cellular pathology associated with GRN insufficiency by using fibroblasts derived from FTD patients carrying the c.709-1G>A GRN mutation (FTD-GRN). These fibroblasts exhibited pathological hallmarks of FTD, including lysosomes, autophagosomes, and lipofuscin accumulation, mirroring observations in affected patient tissues. Notably, we report mitochondrial abnormalities, characterized by mitochondrial swelling which is associated with decreased mitochondrial respiration, and lipid droplet accumulation, reflecting altered lipid metabolism. Experimental supplementation with recombinant human progranulin (rhPGRN) was associated with recovery of lysosomal acidification and attenuation of mitochondrial and lipid abnormalities in vitro. This study reveals that GRN haploinsufficiency induces mitochondrial and lipid dysfunctions, suggesting that these pathways may contribute to FTD-GRN pathogenesis and could be of interest for therapeutic development.

Keywords:  FTD; GRN; frontotemporal dementia; lipid droplets; lysosome; mitochondria; neurodegeneration; progranulin

DOI:  https://doi.org/10.3390/cells15030276
Sci Adv. 2026 Feb 13. 12(7): eadz5645

VMAT2 dysfunction impairs vesicular dopamine uptake, driving its oxidation and α-synuclein pathology in DJ-1-linked Parkinson's neurons.

Leonie M Heger, Francesco Gubinelli, Andreas J Huber, Aida Cardona-Alberich, Matteo Rovere, Ulf Matti, Stephan A Müller, Sankarshana R Nagaraja, Lena Jaschkowitz, Martina Schifferer, Wolfgang Wurst, Stefan F Lichtenthaler, Christian Behrends, Sivakumar Sambandan, Lena F Burbulla.

Parkinson's disease (PD) is characterized by α-synuclein accumulation and dopaminergic neuron degeneration, with dopamine (DA) oxidation emerging as a key pathological driver. However, the mechanisms underlying this neurotoxic process remain unclear. Using PD patient-derived and CRISPR-engineered induced pluripotent stem cell midbrain dopaminergic neurons lacking DJ-1, we identified defective sequestration of cytosolic DA into synaptic vesicles, which culminated in DA oxidation and α-synuclein pathology. In-depth proteomics, state-of-the-art imaging, and ultrasensitive DA probes uncovered that decreased vesicular monoamine transporter 2 (VMAT2) protein and function impaired vesicular DA uptake, resulting in reduced vesicle availability and abnormal vesicle morphology. Furthermore, VMAT2 activity and vesicle endocytosis are processes dependent on adenosine 5'-triphosphate (ATP), which is notably reduced in DJ-1-deficient dopaminergic neurons. ATP supplementation restored vesicular function and alleviated DA-related pathologies in mutant dopaminergic neurons. This study reveals an ATP-sensitive mechanism that regulates DA homeostasis through VMAT2 and vesicle dynamics in midbrain dopaminergic neurons, highlighting enhanced DA sequestration as a promising therapeutic strategy for PD.

DOI: https://doi.org/10.1126/sciadv.adz5645
bioRxiv. 2026 Jan 29. pii: 2026.01.28.702105. [Epub ahead of print]

A HaloTag-4R-Tau Pulse-Chase Sensor Reveals Neddylation Inhibition Promotes Degradation of Tau in iNeurons.

Qiang Xiao, Zi Gao, Seth Allen, Danny Garza, Richard I Morimoto, Jeffery W Kelly.

Tau accumulation is a central driver of neurodegenerative diseases, yet strategies to promote its clearance remain limited. We developed a HaloTag-4R-Tau sensor in human iPSC-derived neurons (iNeurons) that enables sensitive monitoring the kinetics of both lysosomal partitioning and overall cellular turnover of tau. Using this sensor, we screened a small collection of small-molecule modulators of proteostasis network function and identified Neddylation inhibition by Pevonedistat as a robust promoter of soluble tau degradation. Mechanistic analysis including proteomic profiling revealed that Neddylation inhibition hastens HaloTag-Tau clearance via compensatory activation of a proteasome-dependent pathway(s) as well as the autophagy-lysosome pathway. Our findings establish a powerful tool for probing tau homeostasis and highlight Neddylation inhibition as a potential therapeutic approach for enhancing both proteasome and lysosome-mediated tau clearance in tauopathies.

DOI: https://doi.org/10.64898/2026.01.28.702105
bioRxiv. 2025 Dec 19. pii: 2025.12.19.695350. [Epub ahead of print]

Genetic regulators of neuronal survival across metabolic environments.

Neal Bennett, Yanilka Soto-Muniz, Jonathan X Meng, Megan Lee, Joyce Yang, Will R Flanigan, Alexander R Pico, Isha H Jain, Ken Nakamura.

Cellular energy metabolism and oxygen availability shape neuronal function and vulnerability, yet the genetic regulators of these metabolic processes in human neurons remain incompletely understood. Here, we performed CRISPR interference (CRISPRi) screens in human induced pluripotent stem cell (iPSC)-derived neurons across four distinct metabolic conditions and at three physiologically relevant oxygen tensions. This combinatorial approach enabled systematic interrogation of gene-environment interactions that govern neuronal metabolic adaptation. We identified genes-including genes associated with Leigh syndrome and autism spectrum disorder-whose importance for cell survival is highly sensitive to environmental context, revealing potential mechanisms underlying metabolic specification and selective neuronal vulnerability in neurological disorders. Our screens also uncovered regulators of neuronal glycolysis, including KIAA1429 and MAPT among others, which are previously uncharacterized modulators of neuronal glucose utilization and metabolic flexibility. Our work nominates candidate metabolic interventions and gene targets for enhancing neuronal resilience under hypoxic or nutrient-limited conditions.

DOI: https://doi.org/10.64898/2025.12.19.695350
Cell Struct Funct. 2026 ;51(1): 55-65

Calcium and magnesium deficiency induces stress granule formation to maintain magnesium homeostasis.

Tomoko Sakihara, Masatsune Tsujioka, Shinya Honda, Shigeomi Shimizu, Satoru Torii.

  Hypocalcemia and hypomagnesemia frequently occur under pathological conditions such as Crohn's disease or during diuretic treatment. However, how the combined deficiency of Ca2+ and Mg2+ affects cellular physiology has remained unclear. In this study, we focused on this issue and found that Ca2+/Mg2+ deprivation is a potent driver of stress granule (SG) formation. When SG formation was inhibited by G3BP1/2 knockdown, Ca2+/Mg2+ deprivation caused a further decrease in intracellular Mg2+ levels and an increase in cell death, indicating that SGs function to mitigate Mg2+ loss and protect cells from death under cation-deficient conditions. Furthermore, we found that the expression of the Mg2+ transporter MAGT1 is upregulated in an SG-dependent manner, and that MAGT1 knockdown further decreases intracellular Mg2+ levels and increases cell death. Collectively, our results demonstrate that SG formation acts as an adaptive mechanism to maintain Mg2+ homeostasis during Ca2+/Mg2+ deficiency.Key words: stress granule, MAGT1, magnesium, calcium.

Keywords:  MAGT1; calcium; magnesium; stress granule

DOI:  https://doi.org/10.1247/csf.25142
bioRxiv. 2026 Feb 05. pii: 2026.02.05.704014. [Epub ahead of print]

Leucettinib-21 decreases dosage effects of DYRK1A in human trisomy 21 iPSC-derived neural cells.

Nicole R West, Mattias F Lindberg, Julien Dairou, Shawn MacGregor, Sahith Puthireddy, Laurent Meijer, Anita Bhattacharyya.

Dysregulated expression and activity of DYRK1A, dual specificity tyrosine phosphorylation regulated kinase 1A, is a feature of several neurodevelopmental and neurodegenerative diseases, including Down syndrome, DYRK1A syndrome, autism spectrum disorders, Alzheimer's disease, and Parkinson's disease. Thus, manipulating DYRK1A activity in the brain has emerged as a potential therapeutic target for neurological disorders. Several DYRK1A inhibitors have shown promise for improving cognition in rodent models of Down syndrome and Alzheimer's disease, for example, but the ability to affect DYRK1A levels or activity in relevant human cells has not been established. We filled this gap by testing the effects of a new DYRK1A inhibitor on trisomy 21 induced pluripotent stem cell derived neural progenitor cells and neurons, where DYRK1A expression and activity are increased. Our results demonstrate that Leucettinib-21, a potent and selective low-molecular weight pharmacological inhibitor of DYRK1A, decreases DYRK1A activity in human trisomy 21 neural progenitor cells and cortical neurons. We show for the first time that Leucettinib-21 reduces DYRK1A activity in a relevant human disease model, supporting future human trials.
Summary Statement: We show for the first time that Leucettinib-21, a pharmacological inhibitor of DYRK1A, decreases DYRK1A activity in a human iPSC-derived neural cell culture model of Down syndrome.

DOI: https://doi.org/10.64898/2026.02.05.704014
Neurosci Appl. 2026 ;5 106982

Old enough to be a model? On the role of maturity in stem cell-based models for neuropsychiatric disorders.

Bingqing He, Erik Smedler.

Mental disorders profoundly influence cognition, emotion, and self-perception, and collectively represent a major cause of global disability. Their onset spans distinct developmental periods, from early childhood in neurodevelopmental conditions such as autism spectrum disorder, through adolescence in eating and obsessive-compulsive disorders, to early adulthood in bipolar disorder and schizophrenia. Twin and family studies have established that these disorders are substantially heritable, and large-scale genomic analyses have identified numerous common and rare risk variants. Yet, the biological mechanisms through which genetic and environmental factors converge to shape disease trajectories remain elusive. Patient-derived induced pluripotent stem cells (iPSCs) have emerged as a promising tool for investigating disease-relevant mechanisms in human neurons and neural circuits. However, most iPSC-derived neural cells and organoids resemble embryonic/fetal-stage brain tissue in both molecular and functional characteristics, raising questions about their relevance for disorders that manifest later in life. In this narrative review, we discuss how developmental timing, both in disease onset and in cellular models, shapes the interpretation of iPSC-based findings. We outline how differences in neuronal maturity may constrain or enable mechanistic insight, summarize emerging methods for accelerating or extending neuronal aging in vitro, and consider how leveraging developmental immaturity might illuminate early pathogenic processes underlying mental disorders.

DOI: https://doi.org/10.1016/j.nsa.2026.106982
Bio Protoc. 2026 Feb 05. 16(3): e5582

High Content In Vitro Survival Assay of Cortical Neurons.

Paolo V Fioretti, Michela Roccuzzo, Enrico Saccon, Maria Pennuto, Manuela Basso.

  Neuronal survival in vitro is usually used as a parameter to assess the effect of drug treatments or genetic manipulation in a disease condition. Easy and inexpensive protocols based on neuronal metabolism, such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), provide a global view of protective or toxic effects but do not allow for the monitoring of cell survival at the single neuronal level over time. By utilizing live imaging microscopy with a high-throughput microscope, we monitored transduced primary cortical neurons from 7-21 days in vitro (DIV) at the single neuronal level. We established a semi-automated analysis pipeline that incorporates data stratification to minimize the misleading impact of neuronal trophic effects due to plating variability; here, we provide all the necessary commands to reproduce it. Key features • The protocol enables monitoring of primary cortical neuron survival from DIV 7 to 21 in 96-well plates following various cellular treatments. • It provides single-cell and real-time imaging resolution, enabling the identification of small changes in viability over time. • It provides a detailed description of semi-automated neuronal detection over time. • It relies on data stratification based on the neuronal starting number, which helps reduce the impact of neuronal trophic effects due to plating variability. • It has been used to assess the effect of glial extracellular vesicles on cortical neurons, as reported in [1].

Keywords:  High content; Lentivirus; Live imaging; Neuronal survival; Primary cultures

DOI:  https://doi.org/10.21769/BioProtoc.5582
Sci Rep. 2026 Feb 13.

Impact of G-quadruplex RNA oxidation on its conformational dynamics and interaction with ALS-associated TDP-43.

Akira Ishiguro.



Keywords:  8-oxoguanine (8OG); Aging; Amyotrophic lateral sclerosis (ALS) (Lou Gehrig disease); G‐quadruplex; RNA; TAR DNA‐binding protein 43 (TDP‐43) (TARDBP)

DOI:  https://doi.org/10.1038/s41598-026-39767-y
Arch Toxicol. 2026 Feb 07.

Tributyltin induces conjugation of ATG8s to single membranes via the V-ATPase-ATG16L1 axis, leading to transcription factor EB activation in human cell lines.

Shunichi Hatamiya, Masatsugu Miyara, Nanako Takahashi, Ami Oguro, Yaichiro Kotake.

  Tributyltin (TBT) is an environmental contaminant that induces diverse toxic effects in mammals, but the cellular mechanisms underlying adaptation to TBT stress remain poorly understood. Conjugation of ATG8s to single membranes (CASM) is a noncanonical LC3‑lipidation pathway activated by various stressors, distinct from canonical autophagy. We previously showed that TBT reduces lysosomal acidity and inhibits autophagy in SH-SY5Y cells. Furthermore, we observed TBT-induced LC3-II accumulation, which was reduced by bafilomycin A1, and tubular LC3-positive structures as hallmarks of CASM. In this study, we investigated whether TBT activates CASM. TBT (700 nM) induced LC3-II accumulation, which was completely blocked by bafilomycin A1 in SH-SY5Y and HeLa cells. Unlike autophagy, TBT induced LC3-II accumulation even under class III PI3K inhibition by wortmannin and in FIP200-knockout cells. Salmonella effector protein SopF, which inhibits V-ATPase-ATG16L1 association required for CASM, inhibited TBT-induced LC3-II accumulation. In FIP200-knockout cells, TBT induced LC3 accumulation on lysosomes, the primary CASM target. TBT also promoted nuclear translocation of transcription factor EB (TFEB) in a SopF-sensitive manner. Together, these results identify CASM as a lysosomal stress response to TBT, induced via the V-ATPase-ATG16L1 axis, leading to TFEB activation. This mechanism provides a toxicological framework for understanding xenobiotic-induced lysosomal adaptations.

Keywords:  CASM; LC3; Lysosome; Noncanonical autophagy; TFEB; Tributyltin

DOI:  https://doi.org/10.1007/s00204-026-04300-7
Neurosci Bull. 2026 Feb 07.

Current Advances and Applications of Retinal Organoids.

Dan-Ni Zhou, Shu-Guang Yang, Saijilafu, Feng-Quan Zhou.

  Retinal organoids (ROs) are three-dimensional in vitro models that replicate the specific cellular composition and inner structure of the retina. Currently, ROs derived from human pluripotent stem cells (hPSCs) have been shown to mimic both the structure and function of the human retina. Furthermore, ROs function as a powerful model system for researchers, facilitating the investigation of the pathogenesis and treatment strategies of retinal diseases. Despite their development for over a decade, ROs remain limited in terms of complexity and clinical application. This review summarizes recent advances in the development of retinal differentiation methods and underscores their potential applications in disease modeling, gene therapy, cell transplantation, and drug screening. In addition, it proposes research directions that are geared towards advancing RO methodologies to further broaden their applications.

Keywords:  3D differentiation; Cell transplantation; Disease modeling; Drug screening; Gene therapy; Human pluripotent stem cells; Retinal organoids

DOI:  https://doi.org/10.1007/s12264-025-01584-0
Biochim Biophys Acta Gen Subj. 2026 Feb 09. pii: S0304-4165(26)00016-4. [Epub ahead of print] 130916

Spatiotemporal regulation of endocytic membrane trafficking by voltage-sensing phosphatase (VSP) in zebrafish enterocytes.

Adisorn Ratanayotha, Natsuki Mizutani, Fumiko Takenaga, Takafumi Kawai, Yasushi Okamura.

  In developing vertebrates, nutrient uptake by specialized epithelial cells is primarily mediated by endocytosis, a process driven by dynamic phosphoinositide remodeling that regulates vesicle formation and endosomal maturation. Voltage-sensing phosphatase (VSP), a unique membrane protein that couples changes in membrane potential to phosphoinositide hydrolysis, is expressed in zebrafish lysosome-rich enterocytes (LREs), which mediate endocytosis-dependent nutrient absorption during development. However, the molecular mechanisms by which zebrafish VSP (Dr-VSP) regulates endocytic membrane trafficking remain unclear. Here, we elucidate by confocal imaging that Dr-VSP localizes to subapical endomembranes and dynamically redistributes to the apical plasma membrane during nutrient uptake, where it promotes early vesicle formation and maintains proper endolysosomal organization. Loss of Dr-VSP reduces early endocytic vesicles and disrupts downstream recycling and lysosomal compartments, leading to defective nutrient absorption. Electrophysiological analyses showed that extracellular or luminal acidic pH suppresses Dr-VSP voltage sensing, consistent with its activity being confined to the apical plasma membrane where voltage, pH, and phosphoinositide conditions are favorable for activation. These findings indicate that Dr-VSP acts as a voltage- and pH-regulated phosphoinositide phosphatase during the early phase of endocytosis at the plasma membrane, preceding lysosomal digestion. This work defines a functional role for VSPs in epithelial nutrient uptake in vertebrate enterocytes and points to a novel electrochemical mechanism underlying membrane trafficking in vertebrates.

Keywords:  Endocytosis; Epithelial physiology; Lysosome-rich enterocyte; Membrane trafficking; Phosphoinositide; Voltage-sensing phosphatase; Zebrafish

DOI:  https://doi.org/10.1016/j.bbagen.2026.130916
bioRxiv. 2026 Feb 07. pii: 2026.02.07.704588. [Epub ahead of print]

Use-dependent regulation of the axonal action potential in parvalbumin-expressing interneurons.

Sophie R Liebergall, Ethan M Goldberg.

The action potential (AP) is thought to be generated at the axon initial segment and to faithfully propagate along the axon. However, data from both invertebrate and mammalian systems show that the axon is an underappreciated locus of activity modulation and neuronal computation. We assessed axonal AP propagation in neocortical parvalbumin-expressing interneurons (PV-INs) during prolonged, high-frequency activity through paired whole-cell somatic and axon-attached patch clamp recordings in acute brain slices from mouse and human. We found that PV-IN axonal AP propagation remains robust during prolonged activity at moderate frequencies, such as during the entrainment to PV-IN firing patterns recorded in awake, behaving mice in vivo. However, prolonged, high-frequency activity during evoked trains of APs and during seizure-like events resulted in changes in the waveform of the axonal (but not somatic) AP, at least in part due to intrinsic use-dependent mechanisms. This use-dependent decrement in the axonal AP waveform is associated with decreases in calcium influx at PV-IN boutons and subsequent PV-IN-mediated synaptic transmission, indicating this phenomenon may lead to a dissociation between somatic and axonal excitability that could shape PV-IN contributions to circuit dynamics during periods of high activity.

DOI: https://doi.org/10.64898/2026.02.07.704588
Mov Disord. 2026 Feb 11.

Parkinson's Disease Patient-Specific Striatum Organoids Show Hallmarks of Increased Inflammation.

Kyriaki Barmpa, Claudia Saraiva, Alise Zagare, Mona Tuzza, Joseph Longworth, Elisa Zuccoli, Katrin Hufnagel, Florian Skwirblies, Ronny Schmidt, Dirk Brenner, Christoph Schröder, Jens C Schwamborn.

   BACKGROUND: Dopaminergic neurons from the substantia nigra pars compacta project their axons into the dorsal striatum, forming the nigrostriatal pathway. In Parkinson's disease (PD), dopaminergic terminals degenerate in the striatum, leading to dopamine depletion, which in turn causes alterations in the basal ganglia circuits that are essential for movement control. However, the reasons for dopaminergic neuron terminal degeneration in the striatum are still not understood. The LRRK2 gene is highly expressed in the striatum, and the LRRK2-G2019S mutation is one of the most common mutations associated with PD. It is therefore tempting to speculate that dysregulations in the striatal functionality can initiate or contribute to the dopaminergic neuron terminals' degeneration.
OBJECTIVES: We aimed to examine the phenotypic differences between healthy and patient striatum organoids carrying the LRRK2-G2019S mutation to assess whether specific alterations in the striatum that are independent of dopaminergic input could contribute to the development of the disease.
METHODS: Striatum organoids were generated using healthy and PD patient-induced pluripotent stem cell lines, and they were cultured until day 80. We evaluated the levels of striatum-specific proteins, and we performed proteomics and kinase activity analysis.
RESULTS: PD striatum organoids revealed increased abundance of DRD2, DARPP32, and CDK5. Proteomics and kinase activity analysis demonstrated an inflammatory phenotype, which was further validated by investigating the occurrence of reactive astrocytes.
CONCLUSIONS: Striatum organoids recapitulate PD-relevant phenotypes autonomously, independent of dopaminergic input. This includes a significant inflammatory phenotype. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Keywords:  LRRK2‐G2019S; Parkinson's disease; inflammation; striatum organoids

DOI:  https://doi.org/10.1002/mds.70176
bioRxiv. 2026 Feb 06. pii: 2026.02.04.703700. [Epub ahead of print]

Exploiting NMR Ensemble Heterogeneity Enables Small Molecule Discovery Against Dynamic Protein-Protein Interfaces.

Hossam Nada, Sungwoo Cho, Ashraf N Abdo, Moustafa Gabr.

Protein-protein interactions governed by conformationally heterogeneous domains remain difficult to drug because ligand-competent states are often absent from single static structures. Here, we present AtlasNMR, a statistical framework that transforms multi-model NMR ensembles into screening-ready conformational hypotheses for small molecule discovery. Using the neuronal nitric oxide synthase (nNOS) PDZ domain that engages the adaptor protein CAPON (NOS1AP) as a model system, AtlasNMR identified two representative conformational states capturing the dominant and minor populations of the NMR ensemble. Ensemble-based virtual screening followed by consensus ranking yielded MC-3 , a small molecule modulator that disrupts the NOS1-NOS1AP interaction in live cells and directly engages the nNOS PDZ domain. MC-3 produced convergent neuroprotective effects in disease-relevant neuronal models by reducing amyloid-β-induced cytotoxicity, suppressing NMDA-driven nitrosative stress, and attenuating pathological tau phosphorylation, while exhibiting a balanced early lead-like ADME and safety profile. Together, this work establishes a generalizable strategy for exploiting NMR ensemble heterogeneity to enable small molecule discovery against dynamic protein-protein interfaces.

DOI: https://doi.org/10.64898/2026.02.04.703700
Cell Biosci. 2026 Feb 13.

The cytoskeleton regulates cytoophidium dynamics in Drosophila ovaries.

Xiao-Jing Liu, Yi-Lan Li, Shu-Yu Pang, Ji-Long Liu, Kun Dou.

  Cytoophidia are filamentous structures composed of CTP synthase (CTPS) and were first identified in the ovarian cells of Drosophila. As a highly conserved, membraneless organelle present across all three domains of life, cytoophidia exhibit dynamic behaviors essential for cellular homeostasis and function. Previous studies have demonstrated that cytoophidia are actively transported from nurse cells to the oocyte, suggesting a potential role in Drosophila oogenesis; however, the molecular and cellular mechanisms governing cytoophidium dynamics remain poorly understood. In this study, we employ live-cell imaging to systematically characterize the spatiotemporal dynamics of cytoophidia and to investigate the underlying regulatory mechanisms. Our findings reveal that cytoophidium dynamics depend on key cytoskeletal components, including microtubules, microfilaments, and myosin II. Disruption of either microtubules or microfilaments results in the disassembly or depolymerization of macro-cytoophidia, underscoring the essential role of the cytoskeleton in maintaining cytoophidium integrity and facilitating proper assembly. Collectively, these results establish that microtubules, microfilaments, and myosin II are pivotal for regulating cytoophidium dynamics. This study provides novel insights into the mechanisms of cytoophidium transport and assembly, and lays a foundation for further investigation of their functional significance in Drosophila oogenesis.

Keywords:   Drosophila ovary; Cytoophidium; Cytoskeleton; Dynamics; Microfilament; Microtubule; Myosin II; Oogenesis

DOI:  https://doi.org/10.1186/s13578-026-01530-1
Int J Mol Sci. 2026 Jan 27. pii: 1274. [Epub ahead of print]27(3):

Lymphoid Organ Architecture and Hematopoiesis Disruption in Spinal Muscular Atrophy: Therapeutic Rescue by SMN Restoration.

Paula Guillamón, Georg Lindner, Joel Guillen, Alaó Gatius, Sílvia Gras, Laura Martínez-España, Lídia Piedrafita, Anaïs Panosa, Olga Tapia, Conchi Mora, Josep E Esquerda, Eduardo F Tizzano, Olga Tarabal, Jordi Calderó.

  Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by loss of the SMN1 gene, reduced levels of SMN protein, and motor neuron degeneration. However, increasing evidence shows that SMA is a multisystemic disease with immune system involvement. We investigated how SMN deficiency affects lymphoid organ development and function using a severe SMA mouse model (SMNΔ7) and postmortem human fetal and postnatal tissues lacking SMN1 and carrying one or two SMN2 copies, consistent with type 0-I SMA. Histology, immunostaining, and flow cytometry were used to examine tissue architecture and immune cell composition. SMNΔ7 mice displayed thymus, spleen, and bone marrow abnormalities, including mislocalization of T- and B-cells and expansion of resident macrophages. Bone marrow analysis revealed impaired B-cell development, suggesting intrinsic hematopoietic defects rather than apoptosis. Early treatment with a nusinersen-like antisense oligonucleotide, administered intracerebroventricularly or subcutaneously, restored SMN2 splicing, improved survival, motor function, and prevented lymphoid pathology. Human SMA samples exhibited similar, though milder, splenic alterations compared to SMNΔ7 mice, while thymic organization remained largely preserved. These findings demonstrate that SMN deficiency disrupts lymphoid organ development through defective bone marrow output and impaired immune cell maturation. Early SMN restoration prevents these abnormalities, highlighting immune dysfunction as a key component of SMA pathology.

Keywords:  SMA; SMN-ASO therapy; SMN∆7 mouse; bone marrow; human; immune system; spleen; thymus

DOI:  https://doi.org/10.3390/ijms27031274
bioRxiv. 2026 Feb 06. pii: 2026.02.05.704107. [Epub ahead of print]

Identification and characterization of the functional LolB ortholog in Bacteroides.

Krista M Armbruster, Rhea Trickannad, Nichollas E Scott, Nicholas A Pudlo, Jesse W Wotring, Eric C Martens, Jonathan Z Sexton, Nicole M Koropatkin.

Bacteroidota are prolific members of the human gut microbiota, influencing overall health through the degradation of various polysaccharides. To aid in this process, these bacteria deploy cell surface lipoproteins, proteins anchored to the membrane by a lipidated N-terminal cysteine. Despite their importance, lipoprotein synthesis and transport in Bacteroidota is not well defined, particularly how lipoproteins reach the outer membrane and cell surface. In Escherichia coli , lipoproteins are inserted into the outer membrane by LolB, the final step of the Lol pathway for localizing lipoproteins, previously thought to be confined to γ- and β-proteobacteria. Herein, we report a structural ortholog of LolB in Bacteroides that rescues the lethal phenotype associated with LolB depletion in E. coli . We demonstrate this ortholog's LolB-like activity through mutagenesis studies and a lipoprotein insertion activity assay. We find that the gene cannot be deleted from Bacteroides , but that depletion does not significantly impact growth on polysaccharides, nor the surface localization of lipoproteins involved in starch degradation. Nonetheless, depletion significantly alters the composition of many proteins in both the inner and outer membranes, while others remain unchanged. Altogether, our findings contribute to elucidating the lipoprotein transport pathway in Bacteroides and how it impacts cell physiology.
Importance: Bacteroidota are abundant members of the human gut microbiota that influence health and disease. These bacteria deploy numerous cell surface lipoproteins that mediate their interactions with the host and play key roles in cell physiology. However, their mechanism(s) of lipoprotein transport is understudied. Here, we used a genetic screen to identify orthologs to E. coli LolB, the protein responsible for lipoprotein insertion into the outer membrane. Our screen revealed a structural ortholog to LolB in Bacteroides that performs this function. We show that when LolB is depleted, lipoproteins still reach the cell surface, even though the overall protein composition of the membrane is significantly altered. Our results broaden the understanding of both lipoprotein transport and Bacteroidota physiology.

DOI: https://doi.org/10.64898/2026.02.05.704107
Annu Rev Biomed Eng. 2026 Feb 10.

Teravoxel Microscopy Image Analysis for Neurological Diseases.

Ziquan Wei, Guorong Wu.

Light-sheet fluorescence microscopy (LSFM) has emerged as a revolutionary imaging modality for investigating intact three-dimensional brain structures at the teravoxel scale. In parallel, high-throughput computational methods, especially deep learning approaches, have opened new avenues for uncovering the pathophysiological mechanisms of neurological diseases through LSFM technology. Recent advances in optics and tissue clearing methods have allowed whole-brain imaging at cellular resolution in three dimensions, and the integration of artificial intelligence has facilitated the identification of disease-related cellular profiles and morphological markers. Machine learning techniques for stitching, segmentation, classification, super-resolution, and registration, therefore, are promoted to uncover biological patterns that are not visible to human eyes yet are related to neuroinflammatory and neurodegenerative diseases. However, analytic pipelines have been designed differently for various animal models and brain structures, leading to challenges in feasibility and compatibility within this emerging field of data-driven LSFM image analysis. Here, we present an overview of current pipelines, examine existing and forthcoming challenges as the LSFM community advances, demonstrate their implications for neurological disease applications, and propose potential solutions.

DOI: https://doi.org/10.1146/annurev-bioeng-110824-012128
J Clin Invest. 2026 Feb 12. pii: e194721. [Epub ahead of print]

Distinct neuronal alterations distinguish two subtypes of sporadic Creutzfeldt-Jakob disease with shared dysfunctional pathways.

Katie Williams, Bradley R Groveman, Simote T Foliaki, Brent Race, Arielle Hay, Ryan O Walters, Tina Thomas, Gianluigi Zanusso, James A Carroll, Cathryn L Haigh.

  Prion diseases are a family of transmissible, neurodegenerative conditions caused by mis-folded proteins called prions. Human cerebral organoids can be infected with prions from sporadic Creutzfeldt-Jakob Disease (sCJD) brain tissue. Initial experiments indicated that the cerebral organoids may be able to differentiate biological properties of different sCJD subtypes and, if so, it would be possible to investigate the pathogenic similarities and differences. Herein, we investigated multiple infections of cerebral organoids with two sCJD subtypes, comparing hallmark features of disease as well as neuronal function and health. Our results show that while all infections produced seeding capable PrP, which increased from 90-180 days post infection, a sCJD subtype preference for protease resistant PrP deposition was observed. Both subtypes caused substantial electrophysiological dysfunction in the infected organoids, which appeared uncoupled from PrP deposition. Neuronal dysfunction was associated with changes in neurotransmitter receptors that differed between the subtypes but produced the same outcome of a shift from inhibitory toward excitatory neurotransmission. Further changes indicated shared deficits in mitochondrial dynamics, and subtype influenced alterations in intracellular signaling pathways, cytoskeletal structure, and the extracellular matrix. We conclude that cerebral organoids demonstrate both common mitochondrial deficits and sCJD subtype specific changes in neurotransmission and organoid architecture.

Keywords:  Cell biology; Infectious disease; Neuroscience; Prions

DOI:  https://doi.org/10.1172/JCI194721