bims-axbals 2026-08-09 papers

bims-axbals

Biomed News

on Axonal biology and ALS

Issue of 2026–08–09
thirty-two papers selected by
TJ Krzystek

Targeting Ubiquitinated Protein Aggregates in Neurodegenerative Diseases: current Status and Future Directions.
Targeting TDP-43 in sporadic amyotrophic lateral sclerosis.
Inhibition of Glutamate Decarboxylase in the Spinal Cord Induces Motor Deficits and Motor Neuron Degeneration.
LRRK2 regulates synaptic function through modulation of actin cytoskeletal dynamics.
Glial cell toxicity in a Drosophila C9orf72 neurodegeneration model.
A multi-well axon array device for evaluation of stimulus responses on human sensory neural spheroid-derived axon fascicles.
Wild-type C9orf72 drives proteasomal dysfunction and mutant aggregates via a Stat1-Isg15 axis in Huntington's disease.
Molecular switches of SQSTM1: the impact of post-translational modifications on autophagy and neurodegeneration.
Distinct competitive and allosteric binding modes of nanobodies targeting EphA4.
NAT10 inhibition corrects nuclear defects in tau mutant human neurons and extends lifespan in a Drosophila tauopathy model.
A single-domain antibody targets aggregation-prone region of α-synuclein to reduce synucleinopathy, rescue neurodegeneration and improve function.
α-Synuclein blocks endoplasmic reticulum co-translational protein translocation early in Parkinson's disease.
Active transport by cytoplasmic dynein sustains dendritic MAP2 localization in developing neurons.
Rab10 Promotes Atlastin-Mediated Endoplasmic Reticulum Membrane Fusion.
From neural development to regenerative medicine: A research journey in stem cell biology, spinal cord repair, and iPSC-based drug discovery.
Temporal changes in metabolism guide oligodendrocyte precursor cell dynamics in aging and multiple sclerosis.
Evaluation of Antisense Oligonucleotide-Associated Neuronal Lysosomal Changes.
Weekend-free and robotics-compatible protocols for high-throughput human-induced pluripotent stem cell maintenance, amplification, and differentiation.
Cortical organoids reveal human-specific role of METTL5 in neurodevelopment via regulation of CHCHD2.
Tau-induced mitochondrial reverse electron transport drives neurodegeneration.
C9orf72-associated and sporadic FTD patient iPSC-microglia show differences in phagocytosis and gene expression.
Mitochondrial homeostasis dysregulation: Potential mechanisms of Alzheimer's disease mediated by TDP-43.
Lysosomal dysfunction drives a transcriptional and epigenetic signature found in disease-associated microglia in neurodegenerative diseases.
Generation of retinitis pigmentosa patient-derived hiPSC lines (IDVi007-A, IDVi007-B) carrying the RHO c.68C > A variant (p.P23H) and CRISPR/Cas9-corrected isogenic hiPSC lines (IDVi007-A-1, IDVi007-A-2, IDVi007-A-3).
Artificial intelligence-based 3D segmentation of tangle-associated TDP-43 in neurodegeneration.
A novel gross deletion in the progranulin gene in four subjects with frontotemporal dementia.
Lysosomal Profiling With LysoTracker For Quantitative Assessment of Cellular Senescence In Human Fibroblasts.
Bruno 1 remodels P-bodies to protect select mRNAs during the early ER stress response.
Organelle contact sites as spatial regulators of lipid fate in adipose tissue metabolic disease.
A molecular switch for coordinating kinesin and dynein transport of mitochondrial cargo.
Mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE): genetics, mechanisms and precision therapy.
Microtubules in Spinal Cord Injury: From Cytoskeletal Dysregulation to Therapeutic Regeneration.

Mol Cell Biol. 2026 Aug 04. 1-19

Targeting Ubiquitinated Protein Aggregates in Neurodegenerative Diseases: current Status and Future Directions.

Masahiko Takahashi, Takayuki Abe, Masahiro Fujii.

  Various cellular stressors inhibit translation initiation and promote ribosome disassembly, thereby transiently inducing stress granules (SGs), dynamic ribonucleoprotein condensates that contain mRNAs and RNA-binding proteins. Although SG assembly is usually reversible, dysregulated SG dynamics can trigger the formation of persistent ubiquitin-positive protein inclusions. There is increasing evidence that this conversion of SGs into insoluble aggregates represents a central pathogenic mechanism in neurodegenerative proteinopathies, such as amyotrophic lateral sclerosis (ALS) and Alzheimer's disease (AD). TAR DNA-binding protein 43 (TDP-43) and Tau are causative factors in ALS and AD, respectively, and both localize to SGs under stress conditions. During disease progression, TDP-43 or Tau within SGs undergoes pathological changes that promote the formation of neurotoxic inclusions, which propagate neuronal dysfunction and death. This review summarizes recent advances in understanding the molecular factors that regulate SG assembly and disassembly, as well as the pathological processes that drive the conversion of SGs into aggregates associated with neurodegenerative diseases. Particular emphasis is placed on the role of the ubiquitin-specific protease 10 (USP10), which modulates SG dynamics and has been mechanistically implicated in both ALS and AD. Finally, we discuss the therapeutic potential of targeting these pathways to mitigate neurodegenerative disease progression.

Keywords:  Alzheimer’s disease; Amyotrophic lateral sclerosis; stress granule; ubiquitin-specific protease 10

DOI:  https://doi.org/10.1080/10985549.2026.2705871
J Neurol. 2026 Aug 01. pii: 498. [Epub ahead of print]273(8):

Targeting TDP-43 in sporadic amyotrophic lateral sclerosis.

Carlos Estevez-Fraga, Rodrigo Alvarez-Velasco, Tariq Afroz, Marcos R Costa, Ana Jovičić, Felix L Yeh, Peter McColgan, Andrea Malaspina, Alexander McCampbell.

  Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder characterized by motor neuron degeneration leading to early mortality. Despite advances in understanding genetic and molecular contributors, effective disease-modifying therapies for sporadic ALS are of limited utility. The identification of the accumulation of TAR DNA-binding protein 43 (TDP-43) in 97% of total ALS cases represents a critical pathogenic hallmark. This review examines key biological mechanisms underlying TDP-43 pathology, emerging therapeutic strategies, and evolving approaches to clinical trial design and biomarker development. TDP-43 loss of nuclear function, leading to widespread RNA missplicing, and inclusion of cryptic exons, represents an early and critical event in ALS pathogenesis causing downstream dysregulation of key neuronal genes such as STMN2 and UNC13A contributing to axonal degeneration and synaptic dysfunction. Therapeutic strategies targeting these pathways are currently under investigation. Additional approaches aim to ameliorate TDP-43 gain-of-function through cytoplasmic TDP-43 aggregation or modulating processes such as stress responses and RNA metabolism, although clinical translation has been challenging. Advances in biomarkers, including neurofilament light chain and cryptic exon-derived peptides, provide tools for developing efficient clinical trials. However, heterogeneity in disease progression and limitations of available clinical endpoints complicate trial design. Integration of biological insights with biomarker-driven patient stratification and optimized trial methodologies is essential to improve clinical trial outcomes. Emerging biomarkers may enable earlier diagnosis, monitoring of therapeutic response, and personalized treatment approaches. Continued alignment of biological discovery with innovative clinical trial design holds promise for advancing effective therapies and transforming the future of ALS.

Keywords:  Amyotrophic lateral sclerosis; Clinical trials; STMN2; TDP-43; UNC13A

DOI:  https://doi.org/10.1007/s00415-026-14023-5
Neurotox Res. 2026 Aug 05. pii: 40. [Epub ahead of print]44(4):

Inhibition of Glutamate Decarboxylase in the Spinal Cord Induces Motor Deficits and Motor Neuron Degeneration.

Elizabeth Colín-Martínez, Uri Nimrod Ramírez-Jarquín, Ricardo Tapia, Clorinda Arias.

  Motor neuron (MN) diseases such as amyotrophic lateral sclerosis (ALS) are characterized by the loss of cortical and spinal MNs. Although the precise mechanisms of MN degeneration are still unknown, downregulation of GABAergic circuits has been identified in both ALS patients and transgenic models of the disease. GABA synthesis depends on the activity of the enzyme glutamate decarboxylase (GAD), of which two isoforms are known: GAD65 and GAD67. To study the effects of decreased GABA synthesis on spinal cord motor function, we analyzed the effects of administering three selective inhibitors of GAD: 3-mercaptopropionic acid (MPA), a competitive inhibitor of GAD, thiosemicarbazide (TSC), and pyridoxal phosphate γ-glutamyl hydrazone (PLPGH), two GAD cofactor blockers. A single dose of any of these inhibitors did not affect motor behavior or MN morphology. However, subchronic (3 days) and chronic (10 days) administration of MPA, TSC or PLPGH in rats caused motor alterations and cellular changes, including episodic myoclonus-like movements, flaccidity in the ipsilateral phalanges, loss of 35-50% of MNs, reactive astrogliosis and decreased GAD activity. These findings suggest that chronic inhibition of GAD can lead to MN degeneration and further suggest that GABA metabolism in the spinal cord may participate in the mechanisms that cause MN death in patients with neurodegenerative diseases such as ALS.

Keywords:  ALS; GABA metabolism; GAD inhibitors; GAD isoforms; Motor neuron degeneration; Rat spinal cord

DOI:  https://doi.org/10.1007/s12640-026-00815-0
Elife. 2026 Aug 06. pii: RP95987. [Epub ahead of print]13

LRRK2 regulates synaptic function through modulation of actin cytoskeletal dynamics.

Giulia Tombesi, Shiva Kompella, Giulia Favetta, Chuyu Chen, Marta Ornaghi, Yibo Zhao, Ester Morosin, Martina Sevegnani, Adriano Lama, Antonella Marte, Ilaria Battisti, Lucia Iannotta, Nicoletta Plotegher, Laura Civiero, Franco Onofri, Britta J Eickholt, Giovanni Piccoli, Giorgio Arrigoni, Dayne Beccano-Kelly, Claudia Manzoni, Loukia Parisiadou, Elisa Greggio.

  Parkinson's disease (PD) is a multisystemic disorder that manifests through motor and non-motor symptoms. Motor dysfunction results from the degeneration of dopamine-producing neurons in the substantia nigra pars compacta. Increasing evidence suggests that synapse dysfunction precedes neuronal loss by years. Still, early synaptic alterations in PD remain poorly understood. Here, we integrate literature meta-analysis and multi-omics with biochemical, imaging, and electrophysiological measurements in Lrrk2 mouse models and human iPSC-derived neurons lacking LRRK2. We demonstrate that brain-derived neurotrophic factor (BDNF) activates LRRK2 in differentiated SH-SY5Y cells and primary mouse neurons, reshaping the LRRK2 interactome toward a network of actin cytoskeleton-related proteins. Gene-ontology analyses of both literature-curated LRRK2 interactors and phospho-proteome from striatal tissues with elevated LRRK2 activity highlight synapse-actin remodeling as major affected pathways. We further observed that loss of LRRK2 impairs BDNF signaling and alters postsynaptic density architecture. Young Lrrk2 knockout mice display structural alterations in dendritic protrusions, a phenotype that normalizes with age. In human iPSC-derived neurons, LRRK2 knockout affects maturation and BDNF-dependent regulation of spontaneous synaptic activity. Taken together, our study discloses a critical role of LRRK2 in BDNF-dependent synaptic modulation and identifies the synaptic actin cytoskeleton as a convergent site of LRRK2-associated pathophysiological processes in PD.

Keywords:  BDNF; LRRK2; Parkinson's disease; actin cytoskeleton; drebrin; human; mouse; neuroscience; synapse

DOI:  https://doi.org/10.7554/eLife.95987
PLoS Genet. 2026 Aug 05. 22(8): e1011909

Glial cell toxicity in a Drosophila C9orf72 neurodegeneration model.

Isabel Hubbard, Josh Dubnau.

The most common genetic cause of both familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is an expanded G4C2 repeat in the first intron of the gene C9orf72. The C9orf72 repeat expansion is bidirectionally transcribed into sense and anti-sense RNA foci, and also produces dipeptide repeats (DPRs) via a non-canonical translation mechanism known as repeat-associated (RAN) translation. Each of these components of the G4C2 repeat expansion cause neurodegenerative effects in animal models when expressed in neurons, but impacts from glial expression are more poorly understood. Here, we use glial cell type-specific expression of individual DPRs, of RNA repeat-only, or of the G4C2 repeat, that produces both DPRs and RNA repeats, to systematically investigate glial toxicity of each component. We find that as with neurons, the GR and G4C2 transgenes produce the highest degree of toxicity when expressed in glia. Each of these transgenes are capable to produce the GR DPR, which also is the most toxic factor in neurons. We demonstrate that both the GR and G4C2 transgenes cause activation of mdg4, an endogenous retrovirus (ERV). Such ERV expression is a hallmark of TDP-43 dysfunction that is commonly observed in C9orf72 patients. We find that glial expression of either the GR or the G4C2 transgene is toxic to glial cells, but such expression does not cause loss nearby neurons. However, blocking apoptotic signaling within glia that express either GR or G4C2 via expression of the p35 caspase inhibitor further exacerbates effects on lifespan and ablating such glia via expression of the proapoptotic reaper gene partially ameliorates these effects. Together, these results indicate that expression of toxic C9orf72 components in glia produces deleterious effects on lifespan, though potentially through different mechanisms than seen in TDP-43 models of ALS/FTD.

DOI: https://doi.org/10.1371/journal.pgen.1011909
Bioelectrochemistry. 2026 Jul 30. pii: S1567-5394(26)00194-5. [Epub ahead of print]173 109408

A multi-well axon array device for evaluation of stimulus responses on human sensory neural spheroid-derived axon fascicles.

Atsushi Saito, Eiko Yoshida, Satoshi Nakasono.

  Understanding the response of sensory neurons involved in pain perception to external stimuli is crucial for developing chronic pain treatments and determining pain thresholds. In the field of drug discovery, cultured neurons derived from human induced pluripotent stem cells (hiPSCs) are used to evaluate pain perception. Recently, three-dimensional axonal tissues derived from hiPSC-derived sensory neural spheroids have been constructed. These three-dimensional axonal tissues can mimic axon fascicles (AFs) found in the peripheral nervous system, making these tissues promising for cellular experiments aimed at overcoming interspecies differences. However, evaluations of physical and pharmacological stimulus responses, focusing on AF function, are insufficient. Here, we develop a multi-well axon array (MAA) device for hiPSC-derived sensory neural spheroids, which has four AFs, and simultaneously evaluate various stimulus responses in these fascicles. Using the MAA device, we assess temporal changes in spontaneous activity during the functional development of axonal fascicles and the responses to thermal and pharmacological stimuli targeting nociceptors. We also confirm that the MAA device allows for electrical stimulation of localized regions within AFs and detection of stimulation-evoked responses. These findings indicate that the MAA device is useful for evaluating the properties of stimulus-evoked responses of AFs.

Keywords:  Axon fascicles; Electrical stimulation; Human sensory neural spheroids; Microelectrode array; Pharmacological stimulation; Thermal stimulation

DOI:  https://doi.org/10.1016/j.bioelechem.2026.109408
Neurotherapeutics. 2026 Aug 05. pii: S1878-7479(26)00140-6. [Epub ahead of print] e00970

Wild-type C9orf72 drives proteasomal dysfunction and mutant aggregates via a Stat1-Isg15 axis in Huntington's disease.

Siew Chin Chan, Chih-Wei Tung, Chih-Yi Chang, Ching-Chun Su, Yi-Ching Chen, Po-Ming Wu, Chia-Yu Tung, Shih-Feng Chen, Hsiao-Ying Kuo, Pei-Hsun Cheng, Chuan-Mu Chen, Shang-Hsun Yang.

  Mutant C9orf72 has been extensively studied as a major genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia, and is also known to generate Huntington's disease (HD)-like phenocopies. However, despite this strong disease association, the role of wild-type C9orf72 (wt-C9orf72) in neurodegeneration remains largely unexplored. HD is a neurodegenerative disease, and characterized by the accumulation of misfolded mutant Huntingtin (mHTT) and impaired proteostasis, yet the upstream mechanisms driving ubiquitin-proteasome system (UPS) dysfunction are not fully understood. Here, we identify a previously unrecognized modulatory role of wt-C9orf72 in regulating mHTT aggregation in experimental HD models. Analysis of public transcriptomic datasets reveal context-dependent C9ORF72 expression changes across HD-related human datasets, while C9orf72 levels are increased in R6/2 mouse brain lysates. Functional analyses reveal that overexpression of wt-C9orf72 increases mHTT aggregation and is accompanied by increased apoptotic signaling and reduced cell viability. Unbiased proteomic profiling identifies Stat1 as a key downstream effector. Mechanistically, wt-C9orf72 promotes Stat1 activation and nuclear translocation, leading to transcriptional upregulation of Isg15, a ubiquitin-like modifier. Elevated Isg15 disrupts UPS function, resulting in accumulation of polyubiquitinated proteins and impaired proteasomal degradation. Importantly, genetic suppression of Stat1 or Isg15 significantly attenuates C9orf72-associated mHTT aggregation, supporting a functional C9orf72-Stat1-Isg15 axis. Consistent with these cell-based findings, Stat1, phosphorylated Stat1 and Isg15 levels are elevated in the cortex and striatum of R6/2 HD mouse brains. Collectively, our findings identify a novel wt-C9orf72-Stat1-Isg15 axis that promotes proteasomal dysfunction and mHTT aggregation, providing new insights into wt-C9orf72-associated protein homeostasis.

Keywords:  Huntington’s disease; Isg15; Stat1; Ubiquitin-proteasome system; Wild-type C9orf72

DOI:  https://doi.org/10.1016/j.neurot.2026.e00970
Autophagy. 2026 Aug 06. 1-17

Molecular switches of SQSTM1: the impact of post-translational modifications on autophagy and neurodegeneration.

F Abrar, D D O Martin.

  SQSTM1/p62 (sequestosome 1) is an important receptor protein involved in many cellular signaling processes, including macroautophagy/autophagy. It is a molecular hub for cellular homeostasis and cellular responses. Within autophagy, SQSTM1 targets ubiquitinated cargo for degradation, maintaining cellular proteostasis. Structurally, SQSTM1 consists of several domains that facilitate its binding to ubiquitinated cargo, the formation of SQSTM1 aggregate inclusions, interactions with MAP1LC3/LC3, and the mediation of clearance via the autophagy pathway. Beyond its structure, post-translational modifications of SQSTM1 dynamically regulate its function within a cell. Post-translational modifications - such as phosphorylation, ubiquitination, acetylation, S-acylation, and S-nitrosylation - are crucial for regulating SQSTM1 function, localization, and interaction with autophagic components, thereby influencing SQSTM1's role in the autophagy pathway. Understanding the role of these protein modifications in modulating autophagy may provide better insight into developing therapeutic strategies for diseases with dysregulated autophagy, such as neurodegenerative diseases. This review will discuss the role of these post-translational modifications in controlling SQSTM1's localization and function in autophagy.Abbreviations: ABHD = α/β-hydrolase domain; AD = Alzheimer Disease; ALS = amyotrophic lateral sclerosis; ATG = autophagy related ; CSNK2/CK2 = casein kinase 2; HD = Huntington Disease; HDAC/KDAC = histone deacetylase/lysine deacetylase; HTT = huntingtin; KAT = lysine acetyltransferase; KEAP1 = kelch like ECH associated protein 1; KIR = KEAP1-interacting region; LIR = LC3-interacting region; LYPLA/APT = lysophospholipase/acyl-protein thioesterase; MAP1LC3/LC3 = microtubule associated protein 1 light chain 3; MEF = mouse embryonic fibroblast; mHTT = mutant huntingtin; MTORC1 = MTOR complex 1; NBR1 = NBR1 autophagy cargo receptor; NEDD4 = NEDD4 E3 ubiquitin protein ligase ; NO = nitric oxide; NFE2L2/Nrf2 = nuclear factor erythroid 2-factor 2; PAT = palmitoyl acyltransferase; PB1 = Phox-BEM1 domain; PE = phosphatidylethanolamine; PLEKHM1 = pleckstrin homology and RUN domain containing M1; PLK2 = polo like kinase 2; PRKA/PKA = protein kinase cAMP-activated; PPT1 = palmitoyl-protein thioesterase 1; RB1CC1 = RB1 inducible coiled-coil 1; SNCA/α-synuclein = synuclein alpha; SNO = S-nitrosothiol; SOD1 = superoxide dismutase 1; SQSTM1 = sequestosome 1; TARDBP/TDP-43 = TAR DNA binding protein ; TBK1 = TANK binding kinase 1; TAX1BP1 = Tax1 binding protein 1; TRIM = tripartite motif containing ; UBA = ubiquitin-associated domain; UBE = ubiquitin-conjugating enzyme; ULK1 = unc-51 like autophagy activating kinase 1; UPS =ubiquitin-proteasome system; USP8 = ubiquitin specific peptidase 8; ZDHHC = zDHHC palmitoyltransferase.

Keywords:  Neuroscience; S-acylation; p62; post-translational modifications; sequestosome 1

DOI:  https://doi.org/10.1080/15548627.2026.2711593
J Biol Chem. 2026 Aug 05. pii: S0021-9258(26)02266-0. [Epub ahead of print] 113394

Distinct competitive and allosteric binding modes of nanobodies targeting EphA4.

He Jiang, Lulu Ding, Chenlu Yang, Guankai Guo, Chao Zhong, Zhiqiang Ma, Haoran Zhu, Jiahua Zhang, Yang Luo, Zhen Liu, Rui Liu, Yu Ding.

  EphA4 signaling is a key negative regulator of axonal regeneration and a genetic modifier of amyotrophic lateral sclerosis (ALS), making EphA4 an attractive but mechanistically underexplored therapeutic target. Although EphA4-targeting nanobodies have shown inhibitory potential, the structural principles governing their binding and inhibitory mechanisms remain largely unknown. Here, we report high-resolution crystal structures of the EphA4 ligand-binding domain (LBD) in complex with four nanobodies (Nb50, Nb53, Nb57, and Nb60), resolved at 1.34-2.21 Å. Nb50, Nb53, and Nb57 competitively engage the canonical ephrin-binding pocket through deep CDR3 insertion, directly mimicking ephrin recognition. In contrast, Nb60 adopts a previously unrecognized binding mode, contacting two EphA4 molecules at noncanonical sites in the crystal structure through framework-dominated interactions and supporting a structural model for steric and allosteric restriction of ephrin access. Integrated biophysical analyses reveal distinct thermodynamic and kinetic signatures underlying these binding mechanisms. Together, our findings uncover unexpected structural diversity in nanobody-mediated EphA4 recognition and provide a framework for rational development of EphA4-targeted modulators for ALS and related neurodegenerative conditions.

Keywords:  Amyotrophic Lateral Sclerosis (ALS); Antibody; EphA4; Nanobody; Structure

DOI:  https://doi.org/10.1016/j.jbc.2026.113394
iScience. 2026 Aug 21. 29(8): 116861

NAT10 inhibition corrects nuclear defects in tau mutant human neurons and extends lifespan in a Drosophila tauopathy model.

Francesco Paonessa, Bernardo Delarue Bizzini, Tom Campbell, Emily Coode, Jonathan Lam, Ravi Solanki, Richard Butler, James Smith, Catherine M Davidson, Delphine Larrieu, Andrea H Brand, Frederick J Livesey.

  Mutations in the gene encoding the microtubule-associated protein tau (MAPT) that are causal for frontotemporal dementia result in nuclear envelope deformation and disrupted nucleocytoplasmic transport when expressed in human neurons. A small-molecule inhibitor of the acetyltransferase NAT10 has been shown to correct similar nuclear membrane defects in Hutchinson-Gilford progeria syndrome, primarily by modulating microtubule dynamics. We report here that NAT10 inhibition and loss of function correct nuclear membrane abnormalities in human MAPT-mutant neurons. Similarly, NAT10 inhibition and haploinsufficiency correct neuronal nuclear shape defects and extend lifespan in vivo in a Drosophila model of tauopathy. NAT10 inhibition changes microtubule dynamics and corrects aberrant nucleocytoplasmic transport, and NAT10 directly interacts with regulators of microtubule dynamics in human MAPT-mutant neurons. We conclude that NAT10 mediates neuronal pathologies in tauopathies and is a potential therapeutic target in these diseases.

Keywords:  Alzheimer’s; Drosophila; MAPT; dementia; human iPSCs; neurodegeneration; tau protein

DOI:  https://doi.org/10.1016/j.isci.2026.116861
bioRxiv. 2026 Jul 10. pii: 2026.07.07.735601. [Epub ahead of print]

A single-domain antibody targets aggregation-prone region of α-synuclein to reduce synucleinopathy, rescue neurodegeneration and improve function.

Pragati, Erin E Congdon, Yixiang Jiang, Hediye Erdjument-Bromage, Huai-Wei Huang, Ruimin Pan, Isabella S Marchal, Xiang-Peng Kong, Thomas A Neubert, Hyung Don Ryoo, Einar M Sigurdsson.

Synucleinopathies are a group of neurodegenerative disorders characterized by the accumulation of aggregated α-synuclein (α-syn), including Parkinson's disease, Dementia with Lewy Bodies, and Multiple System Atrophy. These diseases are marked by locomotor and non-motor impairments, as well as mitochondrial dysfunction and the loss of dopaminergic (DA) neurons. We have developed several anti-α-syn single-domain antibodies (sdAbs) and demonstrated the diagnostic imaging potential of two of them and the acute therapeutic benefit of one in clearing α-syn in a mouse model. However, whether these sdAbs can suppress α-syn-mediated neuronal loss and locomotor impairment in vivo remains unclear. We evaluated the therapeutic potential of five anti-α-syn sdAbs to clear pathological α-syn in mouse neuronal culture and then demonstrated their in vivo efficacy in a Drosophila model of synucleinopathy. The sdAbs differed in their efficacy to lower levels of phospho-serine 129 α-syn, prevent loss of DA neurons, alleviate mitochondrial dysfunction, improve motor function, and prolong survival in synucleinopathy flies. The most effective sdAb, 2H1, has not been reported before. It binds strongly to the aggregation prone region of α-syn and robustly improves all these disease parameters. Additionally, that sdAb is associated with α-syn in the fly neurons, as shown through proximity dependent turboID biotinylation assays. The sdAb-turboID also biotinylated α-syn-associated proteins involved in synapse/vesicle trafficking pathways, pinpointing the location of their intracellular interaction. Our findings provide an insight into the therapeutic mechanism of action of these sdAbs and strongly support their clinical development.

DOI: https://doi.org/10.64898/2026.07.07.735601
Nat Commun. 2026 Aug 06. pii: 7768. [Epub ahead of print]17(1):

α-Synuclein blocks endoplasmic reticulum co-translational protein translocation early in Parkinson's disease.

Chor Lai Lam, Nicholas J F Gatford, Ana Aragón-González, Benedict Tanudjojo, Anis Sahoo, Andrew R Castle, Devika Agarwal, Ashwin Jainarayanan, Svenja S Hester, Navoneel Sen, Justin L P Benesch, Roman Fischer, David Sims, George K Tofaris.

The primary mechanism and subcellular localisation of α-synuclein toxicity in Parkinson's disease pathogenesis remain unknown. We spatially and temporally resolved proteomic and transcriptomic changes in human iPSC-derived dopaminergic neurons with increasing burden of pathological α-synuclein. We found that misfolded α-synuclein proteoforms, signified by the formation of nanoscale intraneuronal puncta, are associated with impaired translocon function at the endoplasmic reticulum (ER). We show that α-synuclein interacts with Sec61A in iPSC-derived dopaminergic neurons and in post-mortem brain tissue from patients with Parkinson's disease. This interaction interferes with the co-translational translocation of ER-processed proteins including the vacuolar-type ATPase V0a1 subunit, glucocerebrosidase, and Cathepsin B, causing defective organelle function such as reduced lysosomal acidification, leading to increased extracellular vesicle release of α-synuclein. Defective ER-translocation was associated with increased ribosomal UFMylation and proteasomal recruitment but not activation of the unfolded protein response. Reduction of pathological α-synuclein by either CRISPRi to decrease α-synuclein expression or pharmacological activation of proteasomal degradation with repurposed drugs mitigates the ER defect. Our study offers a unifying mechanistic link between α-synuclein pathology and dysregulation of diverse organelle-associated proteins that are both Sec61A translocon substrates and genetic modifiers of Parkinson's disease risk. Our data also provide a therapeutic rationale for proteasomal activation in early Parkinson's disease.

DOI: https://doi.org/10.1038/s41467-026-76173-4
J Biol Chem. 2026 Aug 07. pii: S0021-9258(26)02279-9. [Epub ahead of print] 113407

Active transport by cytoplasmic dynein sustains dendritic MAP2 localization in developing neurons.

Yoji Yonemura, Yuri Sakai, Rinaho Nakata, Ayaka Hagita-Tatsumoto, Tomohiro Miyasaka, Hiroaki Misonou.

  MAP2 has been widely used as a marker of neuronal dendrites because of its extensive restriction in the somatodendritic region. Despite that, how the precise localization of such a soluble protein is established and maintained against diffusion has been elusive and long remained a mystery in neuroscience. In this study, using GFP-tagged MAP2 expressed in cultured hippocampal neurons, we discovered a crucial protein region responsible for the localization of MAP2, the serine/proline-rich (S/P) region. Our pulse-chase live-cell imaging revealed the slow but steady migration of MAP2 toward distal dendrites, which was not observed in the presence of a Dynein inhibitor. By integrating these experimental parameters into a mathematical model, we demonstrated that an intermittent active transport mechanism by Dynein is sufficient to explain the observed MAP2 dynamics. In addition, our experiments using a Dynein inhibitor as well as Dynein knockdown, showed that impaired Dynein function leads to mislocalization of MAP2 in the axon. Furthermore, we verified that cytoplasmic Dynein binds to MAP2 through the S/P region in heterologous cells. Finally, we show that the failure of this Dynein-mediated transport mechanism results in the ectopic stabilization of axonal microtubules, thereby disrupting axonal identity. Thus, we propose that the cytoplasmic Dynein recruits and transports free MAP2 toward distal dendrites, thereby maintaining the precise dendritic localization of MAP2. Our findings shed light on the previously unknown mechanism behind MAP2 localization and provide a new direction for soluble protein trafficking research in the field of cell biology of neurons.

Keywords:  Dynein; Neuron; Transport; localization; microtubule‐associated protein (MAP)

DOI:  https://doi.org/10.1016/j.jbc.2026.113407
FASEB J. 2026 Aug 15. 40(15): e72170

Rab10 Promotes Atlastin-Mediated Endoplasmic Reticulum Membrane Fusion.

Minseok Kim, Kongmin Na, Hyeonji Kim, Eunhong Jang, So Young Yoon, Changwook Lee, Youngsoo Jun.

  Intracellular membrane fusion typically involves two distinct classes of GTPases. Dynamin-like GTPases mediate homotypic fusion between organelles, such as mitochondria and the endoplasmic reticulum (ER), while Rab GTPases facilitate fusion of transport vesicles with target membranes through vesicle tethering. Notably, these two classes of GTPases have not previously been implicated in the same fusion event. In this study, we demonstrate that Rab10 promotes ER membrane fusion driven by the dynamin-like GTPase atlastin (ATL). Rab10 interacted physically with ATL2, a human ATL predominantly expressed in non-neuronal cells, and co-localized with ATL2 throughout the ER, including at three-way junctions where fusion occurs. Fusion between ER microsomes isolated from HEK293T cells, in which ATL2 is the primary ATL isoform, was inhibited by affinity-purified anti-Rab10 antibodies, and was reduced in microsomes derived from Rab10 knockout cells. Moreover, co-reconstitution of Rab10 markedly enhanced fusion of ATL2-containing liposomes. Our findings reveal crosstalk between dynamin-like and Rab GTPases during ATL-mediated ER membrane fusion, uncovering a novel regulatory mechanism for organelle dynamics.

Keywords:  Rab10; atlastin; endoplasmic reticulum; membrane fusion; organelle dynamics

DOI:  https://doi.org/10.1096/fj.202503069RR
Regen Ther. 2026 Dec;33 101157

From neural development to regenerative medicine: A research journey in stem cell biology, spinal cord repair, and iPSC-based drug discovery.

Hideyuki Okano.

  This commemorative article reflects on a research journey spanning neural development, stem cell biology, regenerative medicine, and iPSC-based drug discovery. My early work focused on RNA-mediated regulation in the nervous system, including studies on myelin basic protein gene regulation and the identification and functional characterization of the RNA-binding protein Musashi. These studies contributed to the conceptual foundation of neural stem cell biology and helped establish methods for identifying and isolating neural stem/progenitor cells, including those present in the adult human brain. Building on this foundation, my colleagues and I pursued translational research in spinal cord injury, ranging from analyses of injury pathophysiology and molecular interventions to preclinical studies using rodent and non-human primate models. These efforts ultimately led to the first-in-human clinical study of induced pluripotent stem cell-derived neural stem/progenitor cell transplantation for subacute spinal cord injury. In parallel, we developed patient-derived iPSC platforms for neurological disease modeling and drug discovery, particularly for amyotrophic lateral sclerosis, where iPSC-based screening identified Ropinirole as a therapeutic candidate and enabled reverse translational research linking cellular phenotypes with clinical responses. Looking ahead, I argue that the future of regenerative therapy will depend on the continued integration of developmental biology, stem cell science, disease modeling, rehabilitation, and clinical translation to address unmet medical needs in disorders of the central nervous system.

Keywords:  Amyotrophic lateral sclerosis; Induced pluripotent stem cells; Neural stem cells; Regenerative medicine; Spinal cord injury

DOI:  https://doi.org/10.1016/j.reth.2026.101157
Neuron. 2026 Aug 07. pii: S0896-6273(26)00570-2. [Epub ahead of print]

Temporal changes in metabolism guide oligodendrocyte precursor cell dynamics in aging and multiple sclerosis.

Tess Dierckx, Sarah E Wilson, Rebecca Buchanan, Themistoklis M Tsarouchas, Yuhsiang Cheng, Maria Sacconi Nunez, Kelly Strickland, Dena Kumsa, Yohan S S Auguste, Sam Vanherle, Sander Bouwman, Daniela Rojo, Louisa Dal Cengio, Celia Lerma-Martin, Yassene Mohammed, Lucas Schirmer, Jeroen F J Bogie, Bart J L Eggen, Erin M Gibson.

  Impaired oligodendrocyte precursor cell (OPC) differentiation limits myelin renewal in aging and contributes to multiple sclerosis (MS) progression. How aging drives OPC deficits remains incompletely understood. We find dysregulation of genes associated with the circadian clock, including Bmal1, and metabolism in aged compared with young OPCs. Targeted loss of Bmal1 in OPCs drives metabolic dysfunction, leading to cellular senescence and impaired dynamics. OPC proliferation and differentiation occur at different rates throughout the day in young adult mice and become disrupted with aging. Chronotherapeutic targeting of BMAL1-controlled sirtuin signaling restores Bmal1-disrupted OPC dynamics after demyelination via sirtuin 2 (Sirt2)-dependent mechanisms. Induced pluripotent stem cell (iPSC)-derived OPCs from MS patients and MS lesion oligodendroglia recapitulate BMAL1 and SIRT2 disruptions. These findings establish BMAL1 as a key regulator of OPC energy metabolism, sirtuin homeostasis, and senescence. We anticipate that this work will provide a foundation for future studies investigating the interconnected roles of aging, circadian disruption, and myelin biology.

Keywords:  BMAL1; OPCs; aging; circadian; iPSC; metabolism; multiple sclerosis; myelination; oligodendrocyte precursor cells; oligodendrocytes

DOI:  https://doi.org/10.1016/j.neuron.2026.07.015
Nucleic Acid Ther. 2026 Aug 06. 21593337261473518

Evaluation of Antisense Oligonucleotide-Associated Neuronal Lysosomal Changes.

Albert A Mondragon, Kirk W Donovan, Xiaoping Hronowski, Susanne E Swalley, Sarah Lamore, Benbo Gao, Ramiro Massol, Martin Lamb, Branka Grubor, William Meier, Jim Fikes.

  Antisense oligonucleotides (ASOs) are a rapidly growing therapeutic modality that directly modulate splicing or expression of disease-causing genes. ASOs are internalized through various endocytic mechanisms that converge on the endolysosomal pathway. Our work here aims to evaluate changes to the endolysosomal system following repeated ASO exposure. Histological examinations of nonhuman primates following repeated intrathecal administration of ASOs reveal dose-related neuronal microvesicular vacuolation in the hippocampus, cortex, and spinal cord. These changes are not associated with any neuronal degenerative changes or glial activation. Examination by electron microscopy reveals lysosomes containing stacked membranous material. We established an induced pluripotent stem cell-derived motor neuron (iPSC-MN) model that recapitulates these lysosome changes. ASO exposure did not cause any changes in iPSC-MN viability. To characterize lysosomal changes, we isolated lysosomes from iPSC-MNs after ASO treatment and quantified their protein and lipid contents by liquid chromatography-mass spectrometry. Our lipidomics studies documented increases in bis(monoacylglycerol)phosphate and lactosylceramide following ASO administration; proteomic analysis showed changes in several proteins, including decreases in four lysosomal hydrolases (Carboxypeptidase Q, ß-galactosidase, Cathepsin A, and α-l-Fucosidase). Altogether, this work advances our understanding of the cellular consequences following prolonged ASO administration and may guide further investigations to characterize these effects.

Keywords:  ASO; NHP; lipids; lysosome

DOI:  https://doi.org/10.1177/21593337261473518
Stem Cells Transl Med. 2026 Jul 20. pii: szag060. [Epub ahead of print]15(8):

Weekend-free and robotics-compatible protocols for high-throughput human-induced pluripotent stem cell maintenance, amplification, and differentiation.

Mariam Jouni, Sakina Petiwala, Divya Desai, Grzegorz Gawlak, Emily Y Chen, Alexandra Griffiths, Christopher Hogan, Venus E Thomanetz, Cecilia Heyne Lee, Joseph Tamm, Lamiaa Bahnassawy, Elke Käfer, Anja Finck, Sabina Bopp, Kari Barlan, Emma L Wambeke, Daniel Verduzco, Jacob D Painter, Jarel Gandhi, Peter Reinhardt, Anneke I Den Hollander.

   BACKGROUND: Human induced pluripotent stem cells (hiPSCs) are essential tools for disease modeling, drug testing, and regenerative medicine. These applications require differentiation of multiple cell lines in parallel, synchronized production of large numbers of hiPSCs and differentiated cells, and assessment of differentiation efficiency before proceeding to in-depth characterization through molecular and cellular assays. However, hiPSC culture protocols are often laborious manual processes, which affects reproducibility and makes high-throughput applications challenging.
METHODS: We describe high-throughput hiPSC maintenance and amplification protocols that are weekend-free, scalable, and can be performed manually or automated. These optimized protocols enable scale-up of hiPSC production and differentiation to multiple cell types, including endothelial cells, microglia, and retinal pigment epithelial cells.
RESULTS: We characterized the differentiated cells using molecular and cellular assays and demonstrated that cells generated with this approach represent accurate cell identities.
CONCLUSION: The approaches described here enable high-throughput hiPSC applications and improve reproducibility and scalability.If you want, I can also tighten this further to better fit a strict 350-word journal limit or adapt the heading style to a specific journal.

Keywords:  automation; hiPSC differentiation; hiPSC scalability; high throughput; weekend-free

DOI:  https://doi.org/10.1093/stcltm/szag060
Stem Cell Reports. 2026 Aug 06. pii: S2213-6711(26)00238-9. [Epub ahead of print] 103027

Cortical organoids reveal human-specific role of METTL5 in neurodevelopment via regulation of CHCHD2.

Elena M Turkalj, Gugene Kang, Isabelle Liu, Mariami Kuljanishvili, Neda Keyhanvar, Michael C Oldham, Caroline Vissers.

  Methyltransferase-like 5 (METTL5) catalyzes N6-methyladenosine (m6A) modification on 18S rRNA. In humans, loss-of-function mutations in METTL5 cause severe microcephaly and intellectual disability, whereas Mettl5 knockout (KO) animal models display inconsistent and milder phenotypes. To better model human disease, we generated METTL5-KO human-induced pluripotent stem cell (hiPSC)-derived cortical organoids, which exhibit impaired neural progenitor cell (NPC) proliferation and differentiation, leading to reduced ventricle-like structures and significant reductions in cortical organoid diameter. Mechanistically, Ribo-seq analysis revealed broad translational changes in METTL5-KO NPCs consistent with cellular stress responses rather than transcript-specific translational changes. Single-cell RNA-seq identified downregulation of coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2), a mitochondrial regulator of oxidative metabolism. Overexpression of CHCHD2 in METTL5-KO NPCs rescued proliferation and partially rescued oxidative metabolism in NPCs and ventricle formation in organoids. This highlights a previously uncharacterized connection between CHCHD2, oxidative metabolism, and METTL5-mediated regulation of human neurogenesis.

Keywords:  CHCHD2; METTL5; epitranscriptomics; m6A; neural stem cell; neurogenesis; organoids; rRNA

DOI:  https://doi.org/10.1016/j.stemcr.2026.103027
Neuron. 2026 Aug 06. pii: S0896-6273(26)00541-6. [Epub ahead of print]

Tau-induced mitochondrial reverse electron transport drives neurodegeneration.

Wen Li, Suman Rimal, Sunil Bhurtel, Lucas Yeung, Benjamin G Lu, Lea T Grinberg, Salvatore Spina, Maria Inmaculada Cobos Sillero, William W Seeley, Su Guo, Bingwei Lu.

  Hyperphosphorylation and aggregation of tau are pathological hallmarks of tauopathies. Mitochondrial dysfunction is also a common feature of tauopathies. The mechanistic link between tau abnormalities and mitochondrial dysfunction and its relationship to the physiological function of tau, however, is unclear. Here, we demonstrate that tau regulates mitochondrial reverse electron transport (RET), which produces excess reactive oxygen species (ROS), reduces the NAD+/NADH ratio, and is activated by aging or stress. In flies, mice, and human induced pluripotent stem cell (hiPSC)-derived neurons, tau depletion eliminates stress-induced RET and confers resilience. Mechanistically, tau enters mitochondria and directly interacts with the complex I subunit NDUFS3 to promote RET in a phosphorylation-dependent manner. Elevated RET further drives tau hyperphosphorylation, establishing a self-perpetuating pathological loop. Inhibition of RET ameliorates tau toxicity across species. RET regulation thus represents a previously unrecognized normal function of tau that becomes pathological in disease, providing a therapeutic target for various conditions characterized by tau abnormalities and mitochondrial dysfunction.

Keywords:  Alzheimer’s disease; NAD(+)/NADH ratio; NDUFS3; ROS; complex I; mitochondria; phosphorylation; reverse electron transport; tau; tauopathy

DOI:  https://doi.org/10.1016/j.neuron.2026.07.012
Stem Cell Reports. 2026 Aug 06. pii: S2213-6711(26)00237-7. [Epub ahead of print] 103026

C9orf72-associated and sporadic FTD patient iPSC-microglia show differences in phagocytosis and gene expression.

Hannah Rostalski, Tomi Hietanen, Dorit Hoffmann, Sami Heikkinen, Nadine Huber, Ashutosh Dhingra, Salvador Rodriguez-Nieto, Teemu Kuulasmaa, Sohvi Ohtonen, Henna Jäntti, Viivi Pekkala, Stina Leskelä, Petra Mäkinen, Kasper Katisko, Päivi Hartikainen, Šárka Lehtonen, Eino Solje, Jari Koistinaho, Tarja Malm, Anne M Portaankorva, Teemu Natunen, Henna Martiskainen, Mari Takalo, Mikko Hiltunen, Annakaisa Haapasalo.

  C9orf72 hexanucleotide repeat expansion (C9-HRE) is a major genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (FTD). However, approximately half of the FTD patients are sporadic without a clear genetic background. To compare characteristics of microglia from different FTD subtypes, we generated induced pluripotent stem cell-derived microglia (iMG) from sporadic and C9-HRE-carrying behavioral variant FTD (bvFTD) patients and healthy controls. C9-HRE iMG displayed C9-HRE-associated RNA foci and dipeptide repeat proteins. All bvFTD iMG had fewer LAMP2-A-positive vesicles compared to control iMG. Additionally, C9-HRE iMG showed significantly increased LC3BII/I conversion after bafilomycin A1 treatment and altered phagocytic activity. The gene expression profile of C9-HRE iMG only modestly differed from the control iMG, but was greatly different from the sporadic bvFTD patient iMG. Our data show alterations in phagocytic and autophagosomal/lysosomal pathways and gene expression profiles between C9-HRE and sporadic bvFTD iMG for the first time.

Keywords:  ALS; C9orf72 hexanucleotide repeat expansion; FTD; RNA sequencing; microglia; phagocytosis

DOI:  https://doi.org/10.1016/j.stemcr.2026.103026
Ageing Res Rev. 2026 Aug 05. pii: S1568-1637(26)00282-5. [Epub ahead of print] 103290

Mitochondrial homeostasis dysregulation: Potential mechanisms of Alzheimer's disease mediated by TDP-43.

Wendi Huang, Juan Huang, Nanyu Kuang, Jingjing Wu, Fei Feng, Yong Luo, Nanqu Huang.

  Alzheimer's disease (AD) exhibits substantial clinical and pathological heterogeneity that is not fully explained by amyloid-β and tau pathology alone. TAR DNA-binding protein 43 (TDP-43) is increasingly recognized as a frequent copathology in AD, particularly in limbic regions, where its presence is associated with accelerated cognitive decline. Disruption of mitochondrial homeostasis is also an early and consistent feature of AD and contributes to neuronal vulnerability. In this review, we summarize current evidence linking TDP-43 pathology to impaired mitochondrial homeostasis in AD. We outline key features of mitochondrial homeostasis in neurons, review neuropathological and clinical data supporting the relevance of TDP-43 in AD, and synthesize emerging mechanisms by which TDP-43 may perturb mitochondrial homeostasis, including effects on expression, aggregation and localization, quality control, organelle dynamics, and endoplasmic reticulum-mitochondria communication.

Keywords:  Alzheimer's Disease; Mitochondrial fission; Mitochondrial fusion; Mitochondrial homeostasis; Mitophagy; TDP-43

DOI:  https://doi.org/10.1016/j.arr.2026.103290
Immunity. 2026 Aug 03. pii: S1074-7613(26)00307-9. [Epub ahead of print]

Lysosomal dysfunction drives a transcriptional and epigenetic signature found in disease-associated microglia in neurodegenerative diseases.

Christopher D Balak, Johannes C M Schlachetzki, Addison J Lana, Elizabeth West, Christine Hong, Jordan DuGal, Yi Zhou, Benjamin Li, Nathanael J Spann, Payam Saisan, Vishal Sarsani, Kilian L Kleemann, Xiaoming Zhang, Martina P Pasillas, Sydney O'Brien, Juliette A Bokor, Philip L S M Gordts, Oleg Butovsky, Beth Stevens, Fredrik Kamme, Christopher K Glass.

  Lysosomal dysfunction is causally linked to neurodegeneration in many lysosomal storage disorders and is associated with various age-related neurodegenerative diseases. Here, we investigated the question of underlying mechanisms using a mouse model of mucopolysaccharidosis type IIIA caused by deficiency of the lysosomal hydrolase SGSH. Systematic imaging and transcriptomic and epigenetic studies revealed microglia to be the most profoundly impacted cell type in brains of Sgsh-deficient mice. Further investigation identified dominant and context-dependent roles of members of the MITF/TFE family as major drivers of microglia-specific epigenetic and transcriptional changes resulting from lysosomal stress that are dependent on collaborative interactions with AP-1/ATF, C/EBP, and PU.1/ETS transcription factors. Features of the transcriptomic and epigenetic alterations observed in murine Sgsh deficiency were also observed in microglia derived from mouse models of age-related neurodegeneration and in human Alzheimer's disease patients. These findings reveal common and disease-specific transcriptional mechanisms associated with disease-associated microglia phenotypes.

Keywords:  ChIP-seq; MITF; MPS-IIIA; TFE3; disease-associated microglia; epigenetics; lysosomal storage disorder; lysosome; microglia; neurodegeneration

DOI:  https://doi.org/10.1016/j.immuni.2026.07.008
Stem Cell Res. 2026 Jun 19. pii: S1873-5061(26)00138-8. [Epub ahead of print]95 104042

Generation of retinitis pigmentosa patient-derived hiPSC lines (IDVi007-A, IDVi007-B) carrying the RHO c.68C > A variant (p.P23H) and CRISPR/Cas9-corrected isogenic hiPSC lines (IDVi007-A-1, IDVi007-A-2, IDVi007-A-3).

Marilou Clémençon, Jérémy Brogard, Marie Rozen, Camille Hourton, Rodrigo Meléndez García, Stéphanie Bigou, Stephen H Tsang, Olivier Thouvenin, Kate Grieve, Sacha Reichman.

The p.Pro23His (c.68C > A; P23H) mutation leads to autosomal dominant retinitis pigmentosa (adRP). Here, we reprogrammed adRP patient fibroblasts in human induced pluripotent stem cells (hiPSCs) using Sendai virus. We then generated two mutated hiPSC clones and three isogenic controls using CRISPR/Cas9. All five hiPSC lines express pluripotency genes and are able to differentiate into the three germ layers as well as retinal organoids. Altogether, these hiPSCs constitute unique biological tools to elucidate mechanisms of adRP linked to the RHO-P23H mutation.

DOI: https://doi.org/10.1016/j.scr.2026.104042
Brain Pathol. 2026 Aug 07. e70131

Artificial intelligence-based 3D segmentation of tangle-associated TDP-43 in neurodegeneration.

Gokhan Uruk, Hossam Youssef, Rodolfo G Gatto, Nadia Hossain, Jennifer L Whitwell, Robert R Reichard, Keith A Josephs.

  TAR DNA-binding protein 43 (TDP-43) inclusions are often associated with hyperphosphorylated tau, thus neurofibrillary tangles as the hallmark of Alzheimer's disease (AD) and primary age-related tauopathy (PART). TDP-43 in AD is associated with cognitive impairment, and while staging is known, the localization, cellular and inclusion characteristics of TDP-43 are yet to be elucidated. We investigate relationships between TDP-43 inclusions and the tangle maturation continuum in AD, PART, and co-pathologies by multiplex immunostaining combined with artificial intelligence (AI)-based segmentation via object recognition, reconstruction, and quantification. We performed anti-phosphorylated TDP-43 immunofluorescence with phosphorylated tau labeling different stages and modifications of tangles (AT8, pS396, TauC3, MN423, GT38) in three controls, three cases with PART and TDP-43 (PART-TDP), five cases with high likelihood AD and TDP-43 (AD-TDP), and four cases of high likelihood AD with TDP-43 and Lewy Body disease (AD-TDP-LBD). Confocal imaging was taken from eight regions: amygdala (amygdala-BL and amygdala-CM) and hippocampus (Cornu Ammonis (CA)-1, CA2/3, CA4, dentate gyrus (DG), subiculum (SUB)), and entorhinal cortex (ERC) and quantified with AI segmentation to identify 3D spatial relations, thus the maturity of neurofibrillary tangle associated TDP-43 (TAT) inclusions. TATs, which were either identified by pTDP-43 and AT8 or pTDP-43 and pS396 double positivity, were also investigated by Thioflavin S (ThioS) histochemistry. We found pS396 labeled mature TATs predominated in PART and AD in every region. Basolateral and centromedial amygdala displayed overall greatest number of pre-TATs and mature TATs. Mature TATs were homogenously distributed among hippocampal subfields whereas CA4 and DG had the greatest mature TAT composition. ERC revealed closer numbers of pre-TATs and mature TATs yet mature TATs predominated all groups. Unbiased AI-based object identification, reconstruction, and TAT maturation analysis pipeline in conjunction with TDP-43, tau, and ThioS multiplex immunostaining demonstrated unique aggregation and maturation patterns, highlighting region-specific dynamics in the neurodegenerative processes of PART and AD.

Keywords:  Alzheimer's disease (AD); TAR DNA‐binding protein 43 (TDP‐43); artificial intelligence (AI); neurofibrillary tangle associated TDP‐43 (TAT); phosphorylated tau; primary age‐related tauopathy (PART)

DOI:  https://doi.org/10.1111/bpa.70131
Neurol Sci. 2026 Apr 04. pii: 684. [Epub ahead of print]47(9):

A novel gross deletion in the progranulin gene in four subjects with frontotemporal dementia.

M Ricci, G Di Fede, P Caroppo, V Aprea, C Villa, A Romeo, P Tiraboschi, A Marti, M Grisoli, M M Piccione, S Cimini, Giacomina Rossi.

   BACKGROUND: Mutations in progranulin gene (GRN) are a major cause of frontotemporal dementia (FTD). Most reported pathogenic mutations are nonsense, frameshift, or splicing mutations, resulting in a premature stop codon, degradation of mutated mRNA and consequent protein haploinsufficiency.
OBJECTIVES: In this study, we analysed four subjects with FTD who had low plasma progranulin levels but no mutation detectable by sequencing of GRN, to disclose the underlying genetic cause of disease.
METHODS: Multiplex ligation-dependent probe amplification (MLPA) method was applied to search for rearrangements in GRN. Region-specific polymerase chain reaction (PCR) and Sanger sequencing were performed to define the breakpoint. Quantitative real-time PCR (qRT-PCR) on GRN mRNA and haplotype sharing analysis were also performed.
RESULTS: MLPA revealed in all the subjects the same heterozygous deletion, and a possible common ancestor was suggested by haplotype sharing. PCR and sequencing allowed us to define the size of the deletion (3028 bp), that removes part of GRN promoter, exon 1 including the transcription start site and most of the intron 1, and the breakpoints. qRT-PCR showed reduced level of mRNA, confirming the pathological nature of the deletion.
CONCLUSIONS: In this study, we described a GRN heterozygous gross deletion which removes the consensus sequences for transcription factors and the transcription start site, leading to a reduced levels of plasma progranulin. Our study indicates that GRN rearrangements, although not common, should be investigated in patients with FTD who show low plasma progranulin levels but no GRN mutations detectable by DNA sequencing.

Keywords:  Deletion; Frontotemporal dementia; Haploinsufficiency; MLPA; Mutation; Progranulin

DOI:  https://doi.org/10.1007/s10072-026-09030-3
J Vis Exp. 2026 Jul 17.

Lysosomal Profiling With LysoTracker For Quantitative Assessment of Cellular Senescence In Human Fibroblasts.

Javier Estrada Toro, Scott A Tenenbaum, Melinda Larsen, Thomas J Begley, J Andres Melendez.

Cellular senescence is a stable cell-cycle arrest state associated with characteristic phenotypes, including enlarged cell morphology, altered secretory signaling, and pronounced lysosomal remodeling. Senescent cells commonly exhibit expansion of the acidic endo-lysosomal compartment, accompanied by changes in luminal acidity and degradative capacity, creating an opportunity for simple live-cell readouts of senescence-linked organelle remodeling. This work describes a live-cell imaging protocol that uses LysoTracker Deep Red, an acidotropic fluorescent dye, to provide an indirect, pH-dependent proxy for the acidic organelle compartment as a correlate of senescence burden. The method is demonstrated in IMR-90 human lung fibroblasts undergoing replicative senescence across serial passaging. The protocol details cell culture and passage tracking, LysoTracker staining, fluorescence imaging, and image-based quantification of lysosomal signal intensity and signal-positive area per cell. Senescence-associated β-galactosidase (SA-β-Gal) staining on parallel cultures is included as an optional confirmatory marker rather than a reference standard. Representative outcomes show higher acidotropic fluorescent dye signal and larger lyso-positive regions in late-passage cultures than in early-passage controls, consistent with expansion of the acidic organelle compartment during senescence. Because the readout depends on compartment volume, proton gradient, and dye availability, it is best interpreted as an indirect correlate of lysosomal remodeling rather than a direct measure of lysosome number or biogenesis. The protocol is simple to adopt and can be adapted to other cell types or senescence-inducing stresses, providing a practical, quantitative complement to conventional endpoint assays.

DOI: https://doi.org/10.3791/70684
Life Sci Alliance. 2026 Oct;pii: e202603806. [Epub ahead of print]9(10):

Bruno 1 remodels P-bodies to protect select mRNAs during the early ER stress response.

Samantha N Milano, Livia V Bayer, Julie J Ko, Gwendolyn S Posner, Albina H Granovsky, Diana P Bratu.

P-bodies are cytoplasmic membraneless organelles involved in mRNA storage, yet their role in cellular stress responses remains unresolved. Here, we demonstrate that P-bodies are remodeled during the early response to ER stress throughout Drosophila melanogaster oogenesis. Notably, this remodeling occurs within minutes of stress induction and precedes stress granule formation. This early remodeling is characterized by changes in P-body morphology and internal organization and promotes selective mRNA storage. Mechanistically, we find that this process is driven by transcriptional up-regulation of the RNA-binding protein, Bruno 1, downstream of ATF4-dependent stress signaling, thereby establishing a connection between the unfolded protein response and condensate regulation. Consistent with this model, loss of Bruno 1 abolishes, whereas its overexpression enhances, P-body remodeling, demonstrating that stress-induced changes in RNA-binding protein levels can reprogram condensate properties. Together, our findings reveal that P-bodies function as stress-responsive hubs enabling selective preservation of essential mRNAs during ER stress. More broadly, this work uncovers a previously unrecognized mechanism by which stress signaling pathways reorganize cytoplasmic architecture to shape mRNA fate.

DOI: https://doi.org/10.26508/lsa.202603806
Life Sci. 2026 Aug 07. pii: S0024-3205(26)00433-9. [Epub ahead of print] 124624

Organelle contact sites as spatial regulators of lipid fate in adipose tissue metabolic disease.

Yiqin Yan, Lupeng Chen.

  Adipose tissue protects metabolic homeostasis by storing excess fatty acids, releasing fuels during energy demand and coordinating endocrine and inflammatory signals. These functions are often described as linear pathways of lipogenesis, lipolysis, fatty acid oxidation and thermogenesis. However, lipid handling in adipocytes is spatially organized by organelle contact sites. The endoplasmic reticulum (ER), lipid droplets (LDs), mitochondria, peroxisomes and lysosomes form dynamic interfaces that determine whether fatty acids are stored safely, mobilized for oxidation, processed into specialized lipid species or redirected toward lipotoxic intermediates. In this review, we synthesize evidence that ER-LD and LD-mitochondria contacts coordinate lipid storage and oxidative use, whereas peroxisome-centred contacts connect lipolysis, very-long-chain and branched-chain fatty acid processing, plasmalogen metabolism and mitochondrial remodelling. We further discuss how autophagy and lysosomal pathways maintain adipocyte quality control by regulating LD turnover, mitophagy and membrane renewal. Finally, we propose that obesity, insulin resistance, ectopic lipid deposition, lipodystrophy and adipose inflammation can be viewed as different manifestations of impaired spatial lipid routing. This framework does not replace classical metabolic models, but provides a mechanistic layer that may help identify contact-site-dependent vulnerabilities in metabolic disease.

Keywords:  Adipose tissue; Lipid droplets; Lipophagy; Metabolic disease; Mitochondria; Organelle contact sites; Peroxisomes

DOI:  https://doi.org/10.1016/j.lfs.2026.124624
Science. 2026 Aug 06. 393(6811): 601-606

A molecular switch for coordinating kinesin and dynein transport of mitochondrial cargo.

Christina Gladkova, Maria G Paez-Segala, William P Grant, Mark Kittisopikul, Samuel A Myers, Yuxiao Wang, Ronald D Vale.

The cellular distribution of mitochondria in response to stress and local energy needs is governed by the relative activities of the microtubule-based molecular motors kinesin and dynein. The mechanism for switching between these two opposite-polarity microtubule motors remains unknown. In this study, we coupled a cellular synthetic cargo transport assay with AlphaFold2-guided mutagenesis to identify a regulatory helix in the mitochondrial adaptor protein [trafficking kinesin-binding protein (TRAK)] that mediates switching between kinesin- and dynein-driven transport. Differences in the helix sequence explained why two near-identical TRAK isoforms transported mitochondria in predominantly opposite directions. Phosphorylation of the regulatory helix by stress-activated kinases caused the activation of dynein and dissociation of kinesin. Our results reveal a molecular mechanism for coordinating the directional transport of mitochondria in response to intracellular signals.

DOI: https://doi.org/10.1126/science.aeh1475
Acta Neuropathol. 2026 Aug 02. pii: 14. [Epub ahead of print]152(1):

Mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE): genetics, mechanisms and precision therapy.

James Spyrou, Paul J Lockhart, Snezana Maljevic, Katherine B Howell, Christopher A Reid.

  Mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE) is a recently defined malformation of cortical development that is an important cause of childhood-onset drug-resistant epilepsy. Clinically, the epilepsies associated with MOGHE are heterogeneous, with infantile epileptic spasms syndrome (IESS) being the most common manifestation. Histopathologically, MOGHE demonstrates subtle cortical dyslamination, heterotopic neurons in the white matter, hypomyelination, and a distinctive increase in the density and clustering of oligodendroglial cells, features that distinguish it from other malformations of cortical development such as focal cortical dysplasia (FCD). Recent genetic analyses of epileptogenic tissue resected from individuals with MOGHE have identified somatic mosaic loss-of-function variants in SLC35A2. This gene encodes the Golgi transmembrane UDP-galactose transporter, suggesting disrupted N-glycosylation as a distinct pathogenic mechanism underlying epilepsy in this disorder. In this review, we present the current clinical, histopathological, and molecular understanding of MOGHE, with a particular focus on recent insights gained from experimental rodent and human cellular models of SLC35A2 deficiency. We contextualise these findings against established models of mTORopathies including FCD type 2, placing MOGHE within the broader malformation of cortical development spectrum. Synthesising this evidence, we observe that neuronal activity in models of both MOGHE and mTORopathies such as FCD type 2 converge on reduced action potential firing, despite their distinct genetic aetiologies. Finally, we discuss how these findings inform our understanding of epileptogenesis, especially the emergence of infantile epileptic spasms, and the development of future precision therapeutic strategies across malformations of cortical development.

Keywords:  Epileptogenesis; N-glycosylation; SLC35A2; Somatic mosaicism; mTORopathies

DOI:  https://doi.org/10.1007/s00401-026-03059-6
J Neurochem. 2026 Aug;170(8): e70537

Microtubules in Spinal Cord Injury: From Cytoskeletal Dysregulation to Therapeutic Regeneration.

Itzhak Fischer, Peter W Baas.

  Spinal cord injury (SCI) triggers an immediate and sustained disruption of the composition and organization of the neuronal cytoskeleton. Radical alterations in axonal and dendritic microtubules characterize both the acute injury phase and the protracted recovery period. For decades, researchers have sought to correct these microtubule defects as a therapeutic strategy to encourage axonal regeneration, collateral sprouting, and the functional rewiring of neuronal circuits. Recent studies have demonstrated that taxol and related microtubule-active drugs improve outcomes in rodent models. These benefits are achieved by preventing microtubule depolymerization, stabilizing existing polymers, and promoting new assembly within both afflicted neurons and the glial cells essential for repair. While these findings highlight the therapeutic potential of microtubule-based interventions, we posit that successful clinical translation necessitates a more sophisticated approach rooted in the growing knowledge of microtubule-related proteins and their intricate regulatory mechanisms. This review evaluates progress in this arena, specifically examining the microtubule interactome network that includes structural microtubule-associated proteins (MAPs) such as Tau, MAP1A, MAP1B, MAP2, and MAP6, as well as the stathmin family, plus-end tracking proteins, and microtubule-severing proteins such as fidgetin and spastin. In addition, we analyze the contribution of molecular motor proteins and regulatory MAPs, including CRMP2 and CRMP4, as well as upstream transcription factors governing their expression. Finally, we address convergent regulation through kinases such as GSK3β and CDK5, which represent a central mechanistic axis linking injury signaling to cytoskeletal failure. By integrating data from studies on development and regeneration into a unified mechanistic model, we provide a framework for microtubule-based therapeutics for SCI.

Keywords:  axon; kinase; microtubule; microtubule‐associated proteins; microtubule‐severing enzymes; molecular motor proteins; regeneration/sprouting/repair; spinal cord injury; taxol/epithilone

DOI:  https://doi.org/10.1111/jnc.70537