bims-axbals 2026-02-22 papers

bims-axbals

Biomed News

on Axonal biology and ALS

Issue of 2026–02–22
ten papers selected by
TJ Krzystek

A guide to selecting high-performing antibodies for Optineurin (UniProt ID: Q96CV9) for use in western blot, immunoprecipitation, and immunofluorescence.
C9orf72-derived dipeptide repeat proteins poly-PR disrupt membrane excitability and synaptic function in cortical neurons.
Increased neuronal activity restores circadian function in Drosophila models of C9orf72-ALS/FTD.
The Role of the Golgi Apparatus in Neurodegeneration.
GSK-3β coordinates axonal microtubule organization through Shot and Tau.
Protocol for combining BMP, MEK, WNT inhibition and iNGN2 to enable rapid neuronal differentiation and regional patterning from hiPSCs.
Lysosome pH Dynamics in Physiology and Disease: Molecular Mechanisms and Therapeutic Insights.
Sub-Neuronal Network Profiling of Extracellular Vesicle Release Using a Compartmentalized Neurofluidic Platform.
Spatiotemporal analysis of phosphatidylinositol 4-phosphate dynamics.
Goal-directed learning in cortical organoids.

F1000Res. 2025 ;14 1137

A guide to selecting high-performing antibodies for Optineurin (UniProt ID: Q96CV9) for use in western blot, immunoprecipitation, and immunofluorescence.

Vera Ruíz Moleón, Riham Ayoubi, Charles Alende, Maryam Fothouhi, Joel Ryan, Sara González Bolívar, Donovan Worrall, Thomas M Durcan, Claire M Brown, Vincent Francis, Peter S McPherson, Carl Laflamme.

  Optineurin (OPTN) is a multifunctional cytoplasmic adaptor protein implicated in maintaining neuronal homeostasis through its roles in selective autophagy, vesicle trafficking, and regulation of inflammatory signaling. Mutations in the OPTN gene are causally linked to several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and primary open-angle glaucoma. Here we have eight optineurin commercial antibodies for western blot, immunoprecipitation, and immunofluorescence using a standardized experimental protocol based on comparing read-outs in knockout cell lines and isogenic parental controls. These studies are part of a larger, collaborative initiative seeking to address antibody reproducibility issues by characterizing commercially available antibodies for human proteins and publishing the results openly as a resource for the scientific community. While the use of antibodies and protocols vary between laboratories, we encourage readers to use this report as a guide to select the most appropriate antibodies for their specific needs.

Keywords:  OPTN; Q96CV9; antibody characterization; antibody validation; immunofluorescence; immunoprecipitation; optineurin; western blot

DOI:  https://doi.org/10.12688/f1000research.169966.1
Neurobiol Dis. 2026 Feb 13. pii: S0969-9961(26)00064-1. [Epub ahead of print]221 107320

C9orf72-derived dipeptide repeat proteins poly-PR disrupt membrane excitability and synaptic function in cortical neurons.

Shao-Ming Wang, Jui-Cheng Chan, Engkarat Supapatarnun, Chao-Yi Tsai, Phan Thi Ngoc Lan, Eddie Feng-Ju Weng.

  Amyotrophic lateral sclerosis (ALS) is one of the most fatal neurodegenerative disease, with the most common genetic form of the ALS is associated with hexanucleotide GGGGCC repeat expansions in the first intron of C9orf72 gene. Cortical hyperexcitability is one of the symptoms reported in several forms of ALS and implicated as a cause of neuronal death, however, the underlying mechanisms are still unclear. The dipeptide repeat (DPR) proteins produced from hexanucleotide repeat expansion have been shown toxic to neurons and induce cellular damages. In this study, we explore relationships between the membrane excitability of cortical neurons and the expression of one of the DPR proteins poly-proline-arginine (poly-PR). We found that expression of poly-PR in primary cultured cortical neurons induced an elevation of intrinsic membrane excitability and decreases in dendritic arborization and excitatory synaptic activity. The increased membrane excitability can be restored by Nav channel inhibitor riluzole and Kv7 channel activator retigabine. Our results suggest a rescuable ion channel-mediated hyperexcitability induced by poly-PR expression in cortical neurons, providing a foundation for developing targeted therapies for C9orf72 ALS.

Keywords:  Amyotrophic lateral sclerosis; C9orf72; Hyperexcitability; Poly-PR

DOI:  https://doi.org/10.1016/j.nbd.2026.107320
iScience. 2026 Feb 20. 29(2): 114798

Increased neuronal activity restores circadian function in Drosophila models of C9orf72-ALS/FTD.

Sho Inami, Benjamin P Jenny, Oghenerukevwe Akpoghiran, Sara I Gallagher, Alexandra K Strich, Ayako Tonoki, Davide Trotti, Aaron R Haeusler, Kyunghee Koh.

  Circadian rhythm disruptions are common across neurodegenerative diseases, but their link to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) remains unclear. The C9orf72 hexanucleotide repeat expansion is the most prevalent genetic cause of ALS/FTD. Here, we used Drosophila models expressing pathogenic arginine-rich dipeptides (PR or GR) or GGGGCC hexanucleotide repeats to investigate circadian deficits in C9orf72-ALS/FTD. We found that circadian rhythmicity and period length were altered in a repeat number-, dosage-, expression pattern-, and age-dependent manner. Additionally, we observed lower levels of the neuropeptide PDF, a key regulator of free-running circadian rhythms, as well as decreased projection complexity and reduced neuronal activity in PDF-expressing neurons. Importantly, increases in neuronal activity significantly rescued mild circadian dysfunction across ages and across PR, GR, and GGGGCC repeat models when appropriately tuned. These results implicate reduced neuronal activity in C9orf72-ALS/FTD circadian deficits, underscoring the importance of calibrated, and stage-specific interventions.

Keywords:  Cellular neuroscience; Systems neuroscience

DOI:  https://doi.org/10.1016/j.isci.2026.114798
Subcell Biochem. 2026 ;111 413-440

The Role of the Golgi Apparatus in Neurodegeneration.

Sina Shadfar, Sara Assar Kashani, Shashi Gautam, Zeinab Takalloo, Fabiha Farzana, Sonam Parakh, Julie D Atkin.

  The Golgi apparatus has important, well characterised functions in the trafficking, processing, and post-translational modification of proteins and lipids. However, roles in other cellular processes are increasingly reported, including autophagy, apoptosis, DNA repair, and cytoskeletal (microtubules and actin) function. The Golgi therefore serves as a regulatory hub for multiple signalling pathways that maintain essential cellular activities. The Golgi normally consists of flattened stacks of membrane (cisternae), but during normal physiology and pathological conditions it 'fragments', resulting in altered morphology and distribution. This is well described as an early pathological feature of many neurodegenerative diseases, including Alzheimer's (AD), Parkinson's (PD), Huntington's (HD) and prion diseases, and amyotrophic lateral sclerosis (ALS). These age-related conditions are characterised by the death of neurons: highly specialised, unique cells that form the foundation of the nervous system. Interestingly, many Golgi-related functions are also dysregulated in these diseases. However, this has received relatively little attention compared to other pathogenic mechanisms. The Golgi apparatus in neurons shares features common to other eukaryotic cells but it also has unique properties, such as the presence of distinctive assemblies: Golgi outposts and satellites, which remain poorly characterised. Here we discuss the increasing evidence describing dysfunction and fragmentation of the Golgi apparatus and its possible role in the pathogenesis of neurodegenerative diseases.

Keywords:  Golgi apparatus; Golgi outposts; Neurodegeneration; Neurodegenerative diseases; Neurons; Vesicular transport

DOI:  https://doi.org/10.1007/978-3-032-16833-7_17
Proc Natl Acad Sci U S A. 2026 Feb 24. 123(8): e2516746123

GSK-3β coordinates axonal microtubule organization through Shot and Tau.

André Voelzmann, Lubna Nuhu-Soso, Alex E Roof, Sanjai Patel, Hayley Bennett, Antony Adamson, Gareth J O Evans, Marvin Bentley, Ines Hahn.

  Glycogen Synthase Kinase 3β (GSK-3β) is a key coordinator of neuronal development and maintenance; hyperactive GSK-3β is linked to neurodevelopmental and -degenerative diseases and therefore a promising therapeutic target. In neurons, GSK-3β coordinates the cytoskeleton by phosphorylating microtubule-binding proteins. In this study, we found that tight regulation of GSK-3β kinase activity is required for the maintenance of parallel microtubule bundles in Drosophila and rat axons. Up- or downregulation of GSK-3β led to axons forming pathological swellings in which microtubule bundles disintegrated into disorganized, curled microtubules. We identified the microtubule bundling proteins Shot and Tau as key GSK-3β targets and found that GSK-3β exerted its regulatory effect on microtubule bundling through them. GSK-3β regulates the ability of Shot and Tau to attach to microtubules and/or Eb1. Misregulation of GSK-3β leads to the loss of Eb1-Shot-mediated guidance of polymerizing microtubules into parallel bundles, thus causing disorganization. We propose that microtubule disorganization during both active and inactive states of GSK-3β links its hyperactivity to neurodegeneration and may explain why global GSK-3β inhibition has failed in clinical trials.

Keywords:  GSK-3β; axons; microtubules; neurodegeneration; neurodevelopment

DOI:  https://doi.org/10.1073/pnas.2516746123
STAR Protoc. 2026 Feb 19. pii: S2666-1667(26)00038-9. [Epub ahead of print]7(1): 104385

Protocol for combining BMP, MEK, WNT inhibition and iNGN2 to enable rapid neuronal differentiation and regional patterning from hiPSCs.

Carina Habich, Astrid Doering, Justine D Manos, Miroslav Cik, Peter Reinhardt.

  Neurogenin 2 (iNGN2) overexpression induces human induced pluripotent stem cells (hiPSCs) into neurons but results in a mixed population of peripheral and central nervous system neurons. Pre-differentiation using BMP, MEK, and WNT inhibition ("BMWi") prior to iNGN2 promotes telencephalic neuron differentiation. We outline neural induction, neural progenitor replating/freezing/thawing, and telencephalic neuron maturation and describe protocols for patterning motor neurons, ventral midbrain, and sensory neurons (sensBMi). For complete details on the use and execution of this protocol, please refer to Habich et al.1.

Keywords:  Cell Differentiation; Molecular Biology; Neuroscience; Stem Cells

DOI:  https://doi.org/10.1016/j.xpro.2026.104385
Acta Physiol (Oxf). 2026 Mar;242(3): e70160

Lysosome pH Dynamics in Physiology and Disease: Molecular Mechanisms and Therapeutic Insights.

Sonia Infante-Tadeo, Diane L Barber.

   BACKGROUND: An acidic lysosomal lumen (pH ~4.5) is essential for the degradative and signaling functions of this organelle, which serves as a central hub for cellular homeostasis. Lysosome pH (pHlys), however, is not static but dynamically regulated by the coordinated action of the V-ATPase, counterion fluxes, membrane composition, and nutrient-sensitive signaling networks.
PURPOSE: This review integrates recent advances in the molecular mechanisms regulating pHlys with emerging insights on how dysregulated pHlys contributes to pathologies in neurodegenerative disorders, lysosomal storage diseases, and cancers with changes in lumenal proteolytic activity and macromolecular degradation.
MAIN FINDINGS: We discuss how pHlys acts as both a sensor and effector in lysosome biology, shaping transcriptional responses, membrane trafficking, and stress adaptation. We also review tools to measure pHlys, ranging from fluorescent dyes to genetically encoded biosensors and nanomaterial-based probes, and evaluate their use in disease-modeling applications.
CONCLUSIONS: By highlighting pHlys as a nodal point in cellular functions, this review underscores the relevance of pHlys as a diagnostic marker and therapeutic target. Restoring pHlys in diseases offers translational potential to re-establish proteostasis and limit associated pathologies.

Keywords:  cancer; lysosomal signaling; lysosome pH; neurodegeneration; pHlys regulation

DOI:  https://doi.org/10.1111/apha.70160
Adv Biol (Weinh). 2026 Feb;10(2): e00381

Sub-Neuronal Network Profiling of Extracellular Vesicle Release Using a Compartmentalized Neurofluidic Platform.

Zeynep Malkoc, Esther Stopps, Prince M K Asamoah, Stephanie E McCalla, Anja Kunze.

  Extracellular vesicles (EVs) are membrane-bound vesicles that are secreted by a wide range of organisms and cells, carrying cell-specific receptors and molecular cargo such as proteins and nucleic acids. EVs have emerged as promising biomarkers for cancer and neurodegenerative disorders like Alzheimer's Disease (AD). Traditional methods for isolating neuron-derived EVs from bodily fluids or conditioned media are based on bulk analysis methods, such as ultracentrifugation, isolation reagents, and immunoaffinity-based techniques, and lack spatial resolution to capture localized secretion dynamics. Here, our neurofluidic platform compartmentalizes neuronal networks and enables spatially resolved analysis of EV profiling before subsequent traditional isolation and content screening. This intermediate resolution provides critical insights into localized sub-neuronal EV secretion dynamics in cortical, hippocampal, and brainstem neurons. Using our platform, the influence of growth environment, cell maturation time, and exogenous stressors such as shear and biochemical stress can be unraveled. Biochemical stress is induced through okadaic acid (OA), a PP1A/PP2A inhibitor, which leads to hyperphosphorylation of proteins. In parallel, microRNA expression profiles are shown after OA treatment in primary neuron cultures, indicating an additional transcriptional response. These findings reveal regional differences in EV secretion dynamics associated with neuronal development and external stressors, including shear forces and PP1A/PP2A inhibition.

Keywords:  Cryo‐EM; exosomes; extracellular vesicle profiling; neurofluidics; neuron‐derived micro‐RNA sequencing; okadaic acid

DOI:  https://doi.org/10.1002/adbi.202500381
Methods Enzymol. 2026 ;pii: S0076-6879(25)00493-8. [Epub ahead of print]726 143-155

Spatiotemporal analysis of phosphatidylinositol 4-phosphate dynamics.

Asami Kawasaki, Shinya Tsukiji, Fubito Nakatsu.

  Phosphatidylinositol 4-phosphate (PI4P) is a fundamental phosphoinositide that controls a variety of cellular processes, including signaling, membrane trafficking and intracellular lipid transport. Given the importance of PI4P, tools and methods for monitoring its dynamics are in high demand. We recently identified the pleckstrin homology (PH) domain of oxysterol-binding protein-related protein 9 (ORP9) as a novel genetically encoded probe that enables high-contrast visualization of PI4P across multiple cellular membranes, including the plasma membrane (PM), Golgi, endosomes and lysosomes. Here, we describe methods for imaging and quantifying PI4P dynamics using ORP9-PH with standard confocal microscopy. These approaches include monitoring PI4P distribution at distinct cellular membranes, quantifying PI4P dynamics at the PM in response to pharmacological inhibition of PI 4-kinase and physiological activation of Gq-coupled G protein-coupled receptors. These methods offer a reliable approach for examining the spatial and temporal dynamics of PI4P in situ.

Keywords:  Imaging; Membrane contact site; Oxysterol-binding protein–related protein; Phosphatidylinositol 4-phosphate

DOI:  https://doi.org/10.1016/bs.mie.2025.11.012
Cell Rep. 2026 Feb 19. pii: S2211-1247(26)00062-8. [Epub ahead of print] 116984

Goal-directed learning in cortical organoids.

Ash Robbins, Hunter E Schweiger, Sebastian Hernandez, Alex Spaeth, Kateryna Voitiuk, David F Parks, Tjitse van der Molen, Jinghui Geng, Isabel Cline, Kenneth S Kosik, Sofie R Salama, Tal Sharf, Mohammed A Mostajo-Radji, David Haussler, Mircea Teodorescu.

  Experimental neuroscience techniques are advancing rapidly, with developments in high-density electrophysiology and targeted electrical stimulation enabling single-cell-resolution recording and stimulation. Cortical organoids derived from pluripotent stem cells show great promise as in vitro models of brain development, function, and disease. In this work, we demonstrate goal-directed learning in brain organoids through feedback-driven neural plasticity. We developed a closed-loop electrophysiology framework to embody mouse cortical organoids into a pole-balancing task ("cartpole") and evaluated performance improvements when delivering high-frequency training signals. We found that, for most organoids, training signals chosen by artificial reinforcement learning yield better performance than randomly chosen training signals or no training signal, yet improvements do not persist after the 45-min rest period. We further show that training-induced plasticity requires intact glutamatergic transmission, as pharmacological blockade of AMPA and NMDA receptors abolished performance improvements. This systematic approach to studying goal-directed neural plasticity mechanisms in vitro opens new possibilities for neural rehabilitation and biological computation.

Keywords:  CP: neuroscience; CP: stem cell research; artificial intelligence; biocomputing; causal connectivity; closed-loop control; cortical organoid; electrical stimulation; electrophysiology; in vitro; organoid intelligence; reinforcement learning

DOI:  https://doi.org/10.1016/j.celrep.2026.116984