bims-axbals Biomed News
on Axonal biology and ALS
Issue of 2025–01–05
twenty papers selected by
TJ Krzystek, ALS Therapy Development Institute
  1. Deciphering the interactome of Ataxin-2 and TDP-43 in iPSC-derived neurons for potential ALS targets.
  2. Autophagy receptor-inspired chimeras: a novel approach to facilitate the removal of protein aggregates and organelle by autophagy degradation.
  3. NS1 binding protein regulates stress granule dynamics and clearance by inhibiting p62 ubiquitination.
  4. Decoding TDP-43: the molecular chameleon of neurodegenerative diseases.
  5. NLS-binding deficient Kapβ2 reduces neurotoxicity via selective interaction with C9orf72-ALS/FTD dipeptide repeats.
  6. Parkinson disease-associated toxic exposures selectively upregulate vesicular glutamate transporter vGlut2 in a model of human cortical neurons.
  7. Localized molecular chaperone synthesis maintains neuronal dendrite proteostasis.
  8. Loss of LRRK2 activity induces cytoskeleton defects and oxidative stress during porcine oocyte maturation.
  9. Lineage Recording in Human Brain Organoids with iTracer.
  10. Advances in Aggrephagy: Mechanisms, Disease Implications, and Therapeutic Strategies.
  11. Distinct regulation of Tau Monomer and aggregate uptake and intracellular accumulation in human neurons.
  12. Release of FUS into the extracellular space is regulated by its amino-terminal prion-like domain.
  13. DLK-dependent axonal mitochondrial fission drives degeneration after axotomy.
  14. Selective diagnostics of Amyotrophic Lateral Sclerosis, Alzheimer's and Parkinson's Diseases with machine learning and miRNA.
  15. An Inducible Neural Stem Progenitor Cell Model for Testing Therapeutic Interventions Against Neurodegeneration FENIB.
  16. An unstable variant of GAP43 leads to neurodevelopmental deficiency.
  17. Linear ubiquitination at damaged lysosomes induces local NFKB activation and controls cell survival.
  18. iPSC-derived human sensory neurons reveal a subset of TRPV1 antagonists as anti-pruritic compounds.
  19. Brain organoid methodologies to explore mechanisms of disease in progressive multiple sclerosis.
  20. OSP-1 protects neurons from autophagic cell death induced by acute oxidative stress.
  1. PLoS One. 2024 ;19(12): e0308428
    Deciphering the interactome of Ataxin-2 and TDP-43 in iPSC-derived neurons for potential ALS targets.
    Yuan Tian, Nicolette Heinsinger, Yinghui Hu, U-Ming Lim, Yi Wang, Aaron Zefrin Fernandis, Sophie Parmentier-Batteur, Becky Klein, Jason M Uslaner, Sean M Smith.
      Ataxin-2 is a protein containing a polyQ extension and intermediate length of polyQ extensions increases the risk of Amyotrophic Lateral Sclerosis (ALS). Down-regulation of Ataxin-2 has been shown to mitigate TDP-43 proteinopathy in ALS models. To identify alternative therapeutic targets that can mitigate TDP-43 toxicity, we examined the interaction between Ataxin-2 and TDP-43. Co-immunoprecipitation demonstrated that Ataxin-2 and TDP-43 interact, that their interaction is mediated through the RNA recognition motif (RRM) of TDP-43, and knocking down Ataxin-2 or mutating the RRM domains rescued TDP-43 toxicity in an iPSC-derived neuronal model with TDP-43 overexpression. To decipher the Ataxin-2 and TDP-43 interactome, we used co-immunoprecipitation followed by mass spectrometry to identify proteins that interacted with Ataxin-2 and TDP-43 under conditions of endogenous or overexpressed TDP-43 in iPSC-derived neurons. Multiple interactome proteins were differentially regulated by TDP-43 overexpression and toxicity, including those involved in RNA regulation, cell survival, cytoskeleton reorganization, protein modification, and diseases. Interestingly, the RNA-binding protein (RBP), TAF15 which has been implicated in ALS was identified as a strong binder of Ataxin-2 in the condition of TDP-43 overexpression. Together, this study provides a comprehensive annotation of the Ataxin-2 and TDP-43 interactome and identifies potential therapeutic pathways and targets that could be modulated to alleviate Ataxin-2 and TDP-43 interaction-induced toxicity in ALS.
    DOI:  https://doi.org/10.1371/journal.pone.0308428
  2. J Zhejiang Univ Sci B. 2024 Sep 25. pii: 1673-1581(2024)12-1115-05. [Epub ahead of print]25(12): 1115-1119
    Autophagy receptor-inspired chimeras: a novel approach to facilitate the removal of protein aggregates and organelle by autophagy degradation.
    Liwen Wang, Huimei Liu, Lanfang Li.
      Neurodegenerative diseases (NDDs), mainly including Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), and Alzheimer's disease (AD), are sporadic and rare genetic disorders of the central nervous system. A key feature of these conditions is the slow accumulation of misfolded protein deposits in brain neurons, the excessive aggregation of which leads to neurotoxicity and further disorders of the nervous system.
    Keywords:  Autophagy; Organelle; Protein aggregates; Synthetic autophagy receptors; p62
    DOI:  https://doi.org/10.1631/jzus.B2300853
  3. Nat Commun. 2024 Dec 30. 15(1): 10925
    NS1 binding protein regulates stress granule dynamics and clearance by inhibiting p62 ubiquitination.
    Pureum Jeon, Hyun-Ji Ham, Haneul Choi, Semin Park, Jae-Woo Jang, Sang-Won Park, Dong-Hyung Cho, Hyun-Jeong Lee, Hyun Kyu Song, Masaaki Komatsu, Dohyun Han, Deok-Jin Jang, Jin-A Lee.
      The NS1 binding protein, known for interacting with the influenza A virus protein, is involved in RNA processing, cancer, and nerve cell growth regulation. However, its role in stress response independent of viral infections remains unclear. This study investigates NS1 binding protein's function in regulating stress granules during oxidative stress through interactions with GABARAP subfamily proteins. We find that NS1 binding protein localizes to stress granules, interacting with core components, GABARAP proteins, and p62, a protein involved in autophagy. In cells lacking NS1 binding protein, stress granule dynamics are altered, and p62 ubiquitination is increased, suggesting impaired stress granule degradation. Overexpression of NS1 binding protein reduces p62 ubiquitination. In amyotrophic lateral sclerosis patient-derived neurons, reduced NS1 binding protein and p62 disrupt stress granule morphology. These findings identify NS1 binding protein as a negative regulator of p62 ubiquitination and a facilitator of GABARAP recruitment to stress granules, implicating it in stress granule regulation and amyotrophic lateral sclerosis pathogenesis.
    DOI:  https://doi.org/10.1038/s41467-024-55446-w
  4. Acta Neuropathol Commun. 2024 Dec 31. 12(1): 205
    Decoding TDP-43: the molecular chameleon of neurodegenerative diseases.
    Jixiang Zeng, Chunmei Luo, Yang Jiang, Tao Hu, Bixia Lin, Yuanfang Xie, Jiao Lan, Jifei Miao.
      TAR DNA-binding protein 43 (TDP-43) has emerged as a critical player in neurodegenerative disorders, with its dysfunction implicated in a wide spectrum of diseases including amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), and Alzheimer's disease (AD). This comprehensive review explores the multifaceted roles of TDP-43 in both physiological and pathological contexts. We delve into TDP-43's crucial functions in RNA metabolism, including splicing regulation, mRNA stability, and miRNA biogenesis. Particular emphasis is placed on recent discoveries regarding TDP-43's involvement in DNA interactions and chromatin dynamics, highlighting its broader impact on gene expression and genome stability. The review also examines the complex pathogenesis of TDP-43-related disorders, discussing the protein's propensity for aggregation, its effects on mitochondrial function, and its non-cell autonomous impacts on glial cells. We provide an in-depth analysis of TDP-43 pathology across various neurodegenerative conditions, from well-established associations in ALS and FTLD to emerging roles in diseases such as Huntington's disease and Niemann-Pick C disease. The potential of TDP-43 as a therapeutic target is explored, with a focus on recent developments in targeting cryptic exon inclusion and other TDP-43-mediated processes. This review synthesizes current knowledge on TDP-43 biology and pathology, offering insights into the protein's central role in neurodegeneration and highlighting promising avenues for future research and therapeutic interventions.
    Keywords:  RNA metabolism; TDP-43; chromatin regulation; cryptic exons; mitochondrial dysfunction; neurodegeneration; therapeutic targets
    DOI:  https://doi.org/10.1186/s40478-024-01914-9
  5. Commun Biol. 2025 Jan 02. 8(1): 2
    NLS-binding deficient Kapβ2 reduces neurotoxicity via selective interaction with C9orf72-ALS/FTD dipeptide repeats.
    Kevin M Kim, Amandeep Girdhar, Maria E Cicardi, Vaishnavi Kankate, Miyuki Hayashi, Ruoyu Yang, Jenny L Carey, Charlotte M Fare, James Shorter, Gino Cingolani, Davide Trotti, Lin Guo.
      Arginine-rich dipeptide repeat proteins (R-DPRs) are highly toxic proteins found in patients with C9orf72-linked amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). R-DPRs can cause toxicity by disrupting the natural phase behavior of RNA-binding proteins (RBPs). Mitigating this abnormal phase behavior is, therefore, crucial to reduce R-DPR-induced toxicity. Here, we use FUS as a model RBP to investigate the mechanism of R-DPR-induced aberrant RBP phase transition. We find that this phase transition can be mitigated by Kapβ2. However, as a nuclear import receptor and phase modifier for PY-NLS-containing RBPs, the function of WT Kapβ2 could lead to undesired interaction with its native substrates when used as therapeutics for C9-ALS/FTD. To address this issue, it is crucial to devise effective strategies that allow Kapβ2 to selectively target its binding to the R-DPRs, instead of the RBPs. We show that NLS-binding deficient Kapβ2W460A:W730A can indeed selectively interact with R-DPRs in FUS assembly without affecting normal FUS phase separation. Importantly, Kapβ2W460A:W730A prevents enrichment of poly(GR) in stress granules and mitigates R-DPR neurotoxicity. Thus, NLS-binding deficient Kapβ2 may be implemented as a potential therapeutic for C9-ALS/FTD.
    DOI:  https://doi.org/10.1038/s42003-024-07412-x
  6. Mol Biol Cell. 2025 Jan 02. mbcE24080376
    Parkinson disease-associated toxic exposures selectively upregulate vesicular glutamate transporter vGlut2 in a model of human cortical neurons.
    Karis A Clark, Andrew J White, Wojciech Paslawski, Kellianne D Alexander, Shaoning Peng, Tracy L Young-Pearse, Per Svenningsson, Dennis J Selkoe, Gary P H Ho.
      Parkinson disease (PD) is the second most common neurodegenerative disease, characterized by both motor and cognitive features. Motor symptoms primarily involve midbrain dopaminergic neurons, while cognitive dysfunction involves cortical neurons. Environmental factors are important contributors to PD risk. In rodents, rare midbrain dopaminergic neurons which co-express the vesicular glutamate transporter 2 (vGlut2) are resistant to various toxins which induce dopaminergic neurodegeneration. However, it is unclear how, and with what degree of specificity, cortical glutamatergic neurons respond to PD-associated exposures with respect to vGlut2. Here, we found that vGlut2 in stem cell derived human cortical-like glutamatergic neurons was upregulated in a highly specific manner to certain PD-related chemicals, such as rotenone, but not others, such as paraquat. Further, exposure to recombinant pre-formed fibrils (PFFs) of alpha-synuclein (αS), a protein which accumulates in PD, also increased vGlut2, while fibrils from non-PD related proteins did not. This effect did not involve templated aggregation of endogenous αS. Finally, knockdown of vGlut2 sensitized cortical neurons to rotenone, supporting a functional role in resilience. Thus, upregulation of vGlut2 occurs in a highly selective manner in response to specific PD-associated exposures in a model of cortical glutamatergic neurons, a key cell type for understanding PD dementia.
    DOI:  https://doi.org/10.1091/mbc.E24-08-0376
  7. Nat Commun. 2024 Dec 30. 15(1): 10796
    Localized molecular chaperone synthesis maintains neuronal dendrite proteostasis.
    Célia Alecki, Javeria Rizwan, Phuong Le, Suleima Jacob-Tomas, Mario Fernandez Comaduran, Morgane Verbrugghe, Jia Ming Stella Xu, Sandra Minotti, James Lynch, Jeetayu Biswas, Tad Wu, Heather D Durham, Gene W Yeo, Maria Vera.
      Proteostasis is maintained through regulated protein synthesis and degradation and chaperone-assisted protein folding. However, this is challenging in neuronal projections because of their polarized morphology and constant synaptic proteome remodeling. Using high-resolution fluorescence microscopy, we discover that hippocampal and spinal cord motor neurons of mouse and human origin localize a subset of chaperone mRNAs to their dendrites and use microtubule-based transport to increase this asymmetric localization following proteotoxic stress. The most abundant dendritic chaperone mRNA encodes a constitutive heat shock protein 70 family member (HSPA8). Proteotoxic stress also enhances HSPA8 mRNA translation efficiency in dendrites. Stress-mediated HSPA8 mRNA localization to the dendrites is impaired by depleting fused in sarcoma-an amyotrophic lateral sclerosis-related protein-in cultured spinal cord mouse motor neurons or by expressing a pathogenic variant of heterogenous nuclear ribonucleoprotein A2/B1 in neurons derived from human induced pluripotent stem cells. These results reveal a neuronal stress response in which RNA-binding proteins increase the dendritic localization of HSPA8 mRNA to maintain proteostasis and prevent neurodegeneration.
    DOI:  https://doi.org/10.1038/s41467-024-55055-7
  8. Cell Commun Signal. 2025 Jan 02. 23(1): 2
    Loss of LRRK2 activity induces cytoskeleton defects and oxidative stress during porcine oocyte maturation.
    Yu-Xia Wei, Ya-Han Wang, Xiao-Ting Yu, Lin-Lin Hu, Xiao-Qiong Luo, Shao-Chen Sun.
      Leucine-rich repeat kinase 2 (LRRK2) is a ROCO family member which its mutation is closely related with Parkinson's disease, and LRRK2 is widely involved into the regulation of autophagy, vesicle transport and neuronal proliferation. However, the roles of LRRK2 during mammalian oocyte maturation are still largely unclear. In present study, we disturbed the activity of LRRK2 and showed its essential roles in porcine oocytes. We showed that LRRK2 stably expressed during oocyte maturation, and the loss of LRRK2 activity disturbed cumulus expansion and oocyte polar body extrusion, indicating its involvement into oocyte maturation. Further analysis indicated that LRRK2 was related with cytoskeleton dynamics since its inhibition caused spindle organization defect and chromosome misalignment, and both cytoplasmic and cortex actin decreased. Moreover, LRRK2 co-localized with mitochondria and its activity was essential for mitochondria distribution. Loss of LRRK2 activity altered the TMRE level, which ultimately induced ROS-related oxidative stress. Taken together, our data suggested the important roles of LRRK2 on mammalian oocyte maturation through its effects on cytoskeleton dynamics and mitochondria functions.
    Keywords:  Actin; Mitochondria; Oocyte; Parkinson’s disease; Spindle
    DOI:  https://doi.org/10.1186/s12964-024-01997-w
  9. Methods Mol Biol. 2025 ;2886 85-101
    Lineage Recording in Human Brain Organoids with iTracer.
    Eugenio Gentile, Ashley Maynard, Zhisong He, Barbara Treutlein.
      Induced pluripotent stem cell (iPSC)-derived organoids provide models to study human organ development. Single-cell transcriptomics enables highly resolved descriptions of cell states within these systems; however, approaches are needed to directly determine the lineage relationship between cells. Here we provide a detailed protocol (Fig. 1) for the application of iTracer (He Z, Maynard A, Jain A, et al., Nat Methods 19:90-99, 2022), a recently published lineage recorder that combines reporter barcodes with inducible CRISPR-Cas9 scarring and is compatible with single-cell and spatial transcriptomics. iTracer is used to explore clonality and lineage dynamics during brain organoid development. More broadly, iTracer can be adapted to any iPSC-derived culture system to dissect lineage dynamics during normal or perturbed development.
    Keywords:  Brain organoid; Inducible scarring; Lineage tracing; Single-cell RNA sequencing
    DOI:  https://doi.org/10.1007/978-1-0716-4310-5_5
  10. J Cell Physiol. 2025 Jan;240(1): e31512
    Advances in Aggrephagy: Mechanisms, Disease Implications, and Therapeutic Strategies.
    Haixia Zhuang, Xinyu Ma.
      The accumulation of misfolded proteins within cells leads to the formation of protein aggregates that disrupt normal cellular functions and contribute to a range of human pathologies, notably neurodegenerative disorders. Consequently, the investigation into the mechanisms of aggregate formation and their subsequent clearance is of considerable importance for the development of therapeutic strategies. The clearance of protein aggregates is predominantly achieved via the autophagy-lysosomal pathway, a process known as aggrephagy. In this pathway, autophagosome biogenesis and lysosomal digestion provide necessary conditions for the clearance of protein aggregates, while autophagy receptors such as P62, NBR1, TAX1BP1, TOLLIP, and CCT2 facilitate the recognition of protein aggregates by the autophagy machinery, playing a pivotal role in their degradation. This review will introduce the mechanisms of aggregate formation, progression, and degradation, with particular emphasis on advances in aggrephagy, providing insights for aggregates-related diseases and the development of novel therapeutic strategies.
    Keywords:  aggrephagy; aggrephagy receptors; autophagy; neurodegeneration; protein aggregates
    DOI:  https://doi.org/10.1002/jcp.31512
  11. Mol Neurodegener. 2024 Dec 31. 19(1): 100
    Distinct regulation of Tau Monomer and aggregate uptake and intracellular accumulation in human neurons.
    Amir T Marvian, Tabea Strauss, Qilin Tang, Benjamin J Tuck, Sophie Keeling, Daniel Rüdiger, Negar Mirzazadeh Dizaji, Hossein Mohammad-Beigi, Brigitte Nuscher, Pijush Chakraborty, Duncan S Sutherland, William A McEwan, Thomas Köglsperger, Stefan Zahler, Markus Zweckstetter, Stefan F Lichtenthaler, Wolfgang Wurst, Sigrid Schwarz, Günter Höglinger.
       BACKGROUND: The prion-like spreading of Tau pathology is the leading cause of disease progression in various tauopathies. A critical step in propagating pathologic Tau in the brain is the transport from the extracellular environment and accumulation inside naïve neurons. Current research indicates that human neurons internalize both the physiological extracellular Tau (eTau) monomers and the pathological eTau aggregates. However, similarities or differences in neuronal transport mechanisms between Tau species remain elusive.
    METHOD: Monomers, oligomers, and fibrils of recombinant 2N4R Tau were produced and characterized by biochemical and biophysical methods. A neuronal eTau uptake and accumulation assay was developed for human induced pluripotent stem cell-derived neurons (iPSCNs) and Lund human mesencephalic cells (LUHMES)-derived neurons. Mechanisms of uptake and cellular accumulation of eTau species were studied by using small molecule inhibitors of endocytic mechanisms and siRNAs targeting Tau uptake mediators.
    RESULTS: Extracellular Tau aggregates accumulated more than monomers in human neurons, mainly due to the higher efficiency of small fibrillar and soluble oligomeric aggregates in intraneuronal accumulation. A competition assay revealed a distinction in the neuronal accumulation between physiological eTau Monomers and pathology-relevant aggregates, suggesting differential transport mechanisms. Blocking heparan sulfate proteoglycans (HSPGs) with heparin only inhibited the accumulation of eTau aggregates, whereas monomers' uptake remained unaltered. At the molecular level, the downregulation of genes involved in HSPG synthesis exclusively blocked neuronal accumulation of eTau aggregates but not monomers, suggesting its role in the transport of pathologic Tau. Moreover, the knockdown of LRP1, as a receptor of Tau, mainly reduced the accumulation of monomeric form, confirming its involvement in Tau's physiological transport.
    CONCLUSION: These data propose that despite the similarity in the cellular mechanism, the uptake and accumulation of eTau Monomers and aggregates in human neurons are regulated by different molecular mediators. Thus, they address the possibility of targeting the pathological spreading of Tau aggregates without disturbing the probable physiological or non-pathogenic transport of Tau Monomers.
    Keywords:  Cell-to-cell spreading; Extracellular Tau; HSPGs; LRP1; Neurodegeneration; Uptake; VPS35
    DOI:  https://doi.org/10.1186/s13024-024-00786-w
  12. FEBS Lett. 2024 Dec 29.
    Release of FUS into the extracellular space is regulated by its amino-terminal prion-like domain.
    Tadashi Nakaya.
      Fused in sarcoma (FUS) is a causative factor of amyotrophic lateral sclerosis (ALS) and is believed to propagate pathologically by transmission from cell to cell. However, the mechanism underlying FUS release from cells, which is a critical step for the propagation system, remains poorly understood. This study conducted an analysis of the release of human and mouse FUS from neurons, revealing that human FUS is significantly released into the media compared to its mouse counterpart. Further study using chimeric FUS proteins identified the amino-terminal region of human FUS as essential for its release. These findings indicate that human FUS is released directly from neurons and underscore the novel functional role of its amino-terminal region in this process.
    Keywords:  FUS; extracellular; prion‐like domain
    DOI:  https://doi.org/10.1002/1873-3468.15086
  13. Nat Commun. 2024 Dec 30. 15(1): 10806
    DLK-dependent axonal mitochondrial fission drives degeneration after axotomy.
    Jorge Gómez-Deza, Matthew Nebiyou, Mor R Alkaslasi, Francisco M Nadal-Nicolás, Preethi Somasundaram, Anastasia L Slavutsky, Wei Li, Michael E Ward, Trent A Watkins, Claire E Le Pichon.
      Currently there are no effective treatments for an array of neurodegenerative disorders to a large part because cell-based models fail to recapitulate disease. Here we develop a reproducible human iPSC-based model where laser axotomy causes retrograde axon degeneration leading to neuronal cell death. Time-lapse confocal imaging revealed that damage triggers an apoptotic wave of mitochondrial fission proceeding from the site of injury to the soma. We demonstrate that this apoptotic wave is locally initiated in the axon by dual leucine zipper kinase (DLK). We find that mitochondrial fission and resultant cell death are entirely dependent on phosphorylation of dynamin related protein 1 (DRP1) downstream of DLK, revealing a mechanism by which DLK can drive apoptosis. Importantly, we show that CRISPR mediated Drp1 depletion protects mouse retinal ganglion neurons from degeneration after optic nerve crush. Our results provide a platform for studying degeneration of human neurons, pinpoint key early events in damage related neural death and provide potential focus for therapeutic intervention.
    DOI:  https://doi.org/10.1038/s41467-024-54982-9
  14. Metab Brain Dis. 2025 Jan 02. 40(1): 79
    Selective diagnostics of Amyotrophic Lateral Sclerosis, Alzheimer's and Parkinson's Diseases with machine learning and miRNA.
    Juhyeok Lee, Valentina L Kouznetsova, Santosh Kesari, Igor Tsigelny.
      The diagnosis of neurological diseases can be expensive, invasive, and inaccurate, as it is often difficult to distinguish between different types of diseases with similar motor symptoms. However, the dysregulation of miRNAs can be used to create a robust machine-learning model for a reliable diagnosis of neurological diseases. We used miRNA sequence descriptors and gene target data to create machine-learning models that can be used as diagnostic tools. The top-performing machine-learning models, trained on filtered miRNA datasets for Amyotrophic Lateral Sclerosis, Alzheimer's and Parkinson's Diseases of this research yielded 94, 97, and 96, percent accuracies, respectively. Analysis of dysregulated miRNA in neurological diseases elucidated novel biomarkers that could be used to diagnose and distinguish between the diseases. Machine-learning models developed using sequence and gene target descriptors of miRNA biomarkers can achieve favorable accuracies for disease classification and attain a robust discerning capability of neurological diseases.
    Keywords:  Alzheimer’s disease; Amyotrophic lateral sclerosis; Machine learning; Neurological disease; Parkinson’s disease; miRNA
    DOI:  https://doi.org/10.1007/s11011-024-01490-w
  15. Drug Dev Res. 2025 Feb;86(1): e70041
    An Inducible Neural Stem Progenitor Cell Model for Testing Therapeutic Interventions Against Neurodegeneration FENIB.
    Alessandro Giustini, Alice Maiocchi, Ilaria Serangeli, Martina Pedrini, Anna Quintiliani, Valentina Sabato, Francesca Bonato, Pierfausto Seneci, Giuseppe Lupo, Daniele Passarella, Elena Miranda.
      Familial encephalopathy with neuroserpin inclusion bodies (FENIB) is a neurodegenerative pathology caused by accumulation of mutant neuroserpin (NS) polymers inside the endoplasmic reticulum (ER) of neurons, leading to cellular toxicity and neuronal death. To date, there is no cure for FENIB, and only palliative care is available for FENIB patients, underlining the urgency to develop therapeutic strategies. The purpose of this work was to create a cellular system designed for testing small molecules able to reduce the formation of NS polymers. Our results show the generation and characterisation of a novel cell culture model for FENIB based on neural stem progenitor cells (NPCs) with inducible expression of either wild type (WT) or G392E NS, a variant that causes severe FENIB. We also report the use of these novel cell lines to explore the effects of four different proteolysis targeting chimaera (PROTAC) compounds, small bivalent molecules engineered to bind to the E3 ubiquitin ligase cereblon, and to NS through a recruiting motif based on the small molecule embelin. This approach aims to enhance the degradation of mutant NS after retro-translocation to the cytosol by facilitating its targeting to the proteasome. Our results show little toxicity and no variation in NS levels with any of the compounds tested. In conclusion, this work sets the basis for future attempts to identify molecules able to prevent NS accumulation inside the ER of cultured cells.
    Keywords:  FENIB; PROTAC; cereblon; embelin; neural progenitor cells; neuroserpin
    DOI:  https://doi.org/10.1002/ddr.70041
  16. Sci Rep. 2024 Dec 30. 14(1): 31911
    An unstable variant of GAP43 leads to neurodevelopmental deficiency.
    Mariko Noda, Ayumi Matsumoto, Hidenori Ito, Masayo Kagami, Toshihiro Tajima, Takayoshi Matsumura, Takanori Yamagata, Koh-Ichi Nagata.
      Growth-associated protein 43 (GAP43) is a membrane-associated phosphoprotein predominantly expressed in the nervous systems, and controls axonal growth, branching, and pathfinding. While the association between GAP43 and human neurological disorders have been reported, the underlying mechanisms remain largely unknown. We performed whole exome sequencing on a patient with intellectual disability (ID), neurodevelopmental disorders, short stature, and skeletal abnormalities such as left-right difference in legs and digital deformities, and identified a heterozygous missense variation in the GAP43 gene [NM_001130064.2: c.436G > A/p.(E146K)]. The variant GAP43 protein was unstable in primary cultured cortical neurons and hippocampal neurons in vitro. In utero electroporation of the variant protein also confirmed its instability in vivo, suggesting that the variant led to a condition similar with haploinsufficiency in the patient. Silencing of GAP43 via in utero electroporation of RNAi vectors demonstrated that loss of GAP43 suppressed axon elongation into the contralateral hemisphere and impaired the dendritic arbor formation as shown by decreased dendritic branch points and shortened total dendritic lengths. Collectively, these findings confirmed the critical roles of GAP43 in brain development and the pathological basis of GAP43-associated diseases. Our study will contribute to a better understanding of how dysregulation of GAP43 leads to human diseases.
    DOI:  https://doi.org/10.1038/s41598-024-83445-w
  17. Autophagy. 2025 Jan 02. 1-21
    Linear ubiquitination at damaged lysosomes induces local NFKB activation and controls cell survival.
    Laura Zein, Marvin Dietrich, Denise Balta, Verian Bader, Christoph Scheuer, Suzanne Zellner, Nadine Weinelt, Julia Vandrey, Muriel C Mari, Christian Behrends, Friederike Zunke, Konstanze F Winklhofer, Sjoerd J L Van Wijk.
      Lysosomes are the major cellular organelles responsible for nutrient recycling and degradation of cellular material. Maintenance of lysosomal integrity is essential for cellular homeostasis and lysosomal membrane permeabilization (LMP) sensitizes toward cell death. Damaged lysosomes are repaired or degraded via lysophagy, during which glycans, exposed on ruptured lysosomal membranes, are recognized by galectins leading to K48- and K63-linked poly-ubiquitination (poly-Ub) of lysosomal proteins followed by recruitment of the macroautophagic/autophagic machinery and degradation. Linear (M1) poly-Ub, catalyzed by the linear ubiquitin chain assembly complex (LUBAC) E3 ligase and removed by OTULIN (OTU deubiquitinase with linear linkage specificity) exerts important functions in immune signaling and cell survival, but the role of M1 poly-Ub in lysosomal homeostasis remains unexplored. Here, we demonstrate that L-leucyl-leucine methyl ester (LLOMe)-damaged lysosomes accumulate M1 poly-Ub in an OTULIN- and K63 Ub-dependent manner. LMP-induced M1 poly-Ub at damaged lysosomes contributes to lysosome degradation, recruits the NFKB (nuclear factor kappa B) modulator IKBKG/NEMO and locally activates the inhibitor of NFKB kinase (IKK) complex to trigger NFKB activation. Inhibition of lysosomal degradation enhances LMP- and OTULIN-regulated cell death, indicating pro-survival functions of M1 poly-Ub during LMP and potentially lysophagy. Finally, we demonstrate that M1 poly-Ub also occurs at damaged lysosomes in primary mouse neurons and induced pluripotent stem cell-derived primary human dopaminergic neurons. Our results reveal novel functions of M1 poly-Ub during lysosomal homeostasis, LMP and degradation of damaged lysosomes, with important implications for NFKB signaling, inflammation and cell death.Abbreviation: ATG: autophagy related; BafA1: bafilomycin A1; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CRISPR: clustered regularly interspaced short palindromic repeats; CHUK/IKKA: component of inhibitor of nuclear factor kappa B kinase complex; CUL4A-DDB1-WDFY1: cullin 4A-damage specific DNA binding protein 1-WD repeat and FYVE domain containing 1; DGCs: degradative compartments; DIV: days in vitro; DUB: deubiquitinase/deubiquitinating enzyme; ELDR: endo-lysosomal damage response; ESCRT: endosomal sorting complex required for transport; FBXO27: F-box protein 27; GBM: glioblastoma multiforme; IKBKB/IKKB: inhibitor of nuclear factor kappa B kinase subunit beta; IKBKG/NEMO: inhibitor of nuclear factor kappa B kinase regulatory subunit gamma; IKK: inhibitor of NFKB kinase; iPSC: induced pluripotent stem cell; KBTBD7: kelch repeat and BTB domain containing 7; KO: knockout; LAMP1: lysosomal associated membrane protein 1; LCD: lysosomal cell death; LGALS: galectin; LMP: lysosomal membrane permeabilization; LLOMe: L-leucyl-leucine methyl ester; LOP: loperamide; LUBAC: linear ubiquitin chain assembly complex; LRSAM1: leucine rich repeat and sterile alpha motif containing 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; NBR1: NBR1 autophagy cargo receptor; NFKB/NF-κB: nuclear factor kappa B; NFKBIA/IĸBα: nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha; OPTN: optineurin; ORAS: OTULIN-related autoinflammatory syndrome; OTULIN: OTU deubiquitinase with linear linkage specificity; RING: really interesting new gene; RBR: RING-in-between-RING; PLAA: phospholipase A2 activating protein; RBCK1/HOIL-1: RANBP2-type and C3HC4-type zinc finger containing 1; RNF31/HOIP: ring finger protein 31; SHARPIN: SHANK associated RH domain interactor; SQSTM1/p62: sequestosome 1; SR-SIM: super-resolution-structured illumination microscopy; TAX1BP1: Tax1 binding protein 1; TBK1: TANK binding kinase 1; TH: tyrosine hydroxylase; TNF/TNFα: tumor necrosis factor; TNFRSF1A/TNFR1-SC: TNF receptor superfamily member 1A signaling complex; TRIM16: tripartite motif containing 16; Ub: ubiquitin; UBE2QL1: ubiquitin conjugating enzyme E2 QL1; UBXN6/UBXD1: UBX domain protein 6; VCP/p97: valosin containing protein; WIPI2: WD repeat domain, phosphoinositide interacting 2; YOD1: YOD1 deubiquitinase.
    Keywords:  Cell death; LUBAC; NF-κB; OTULIN; linear ubiquitination; lysosomes
    DOI:  https://doi.org/10.1080/15548627.2024.2443945
  18. Sci Rep. 2024 12 28. 14(1): 31182
    iPSC-derived human sensory neurons reveal a subset of TRPV1 antagonists as anti-pruritic compounds.
    Shermaine Huiping Tay, Jeremy Kah Sheng Pang, Winanto Ng, Chong Yi Ng, Zi Jian Khong, Zheng-Shan Chong, Boon Seng Soh, Shi-Yan Ng.
      Signaling interplay between the histamine 1 receptor (H1R) and transient receptor potential cation channel subfamily V member 1 (TRPV1) in mediating histaminergic itch has been well-established in mammalian models, but whether this is conserved in humans remains to be confirmed due to the difficulties in obtaining human sensory neurons (SNs) for experimentation. Additionally, previously reported species-specific differences in TRPV1 function indicate that use of human SNs is vital for drug candidate screening to have a higher chance of identifying clinically effective TRPV1 antagonists. In this study, we built a histamine-dependent itch model using peripheral SNs derived from human induced pluripotent stem cells (hiPSC-SNs), which provides an accessible source of human SNs for pre-clinical drug screening. We validated channel functionality using immunostaining, calcium imaging, and multielectrode array (MEA) recordings, and confirmed the interdependence of H1R and TRPV1 signalling in human SNs. We further tested the amenability of our model for pre-clinical studies by screening multiple TRPV1 antagonists in parallel, identifying SB366791 as a potent inhibitor of H1R activation and potential candidate for alleviating histaminergic itch. Notably, some of the results using our model corroborated with efficacy and side effect findings from human clinical trials, underscoring the importance of this species-specific platform. Taken together, our results present a robust in vitro human model for histaminergic itch, which can be used to further interrogate the molecular basis of human SN function as well as screen for TRPV1 activity-modifying compounds for a number of clinical indications.
    Keywords:  Histamine receptor; Human pluripotent stem cells; Itch; MEA; Sensory neurons; TRPV1; TRPV1 antagonist
    DOI:  https://doi.org/10.1038/s41598-024-82549-7
  19. Front Cell Neurosci. 2024 ;18 1488691
    Brain organoid methodologies to explore mechanisms of disease in progressive multiple sclerosis.
    Madalena B C Simões-Abade, Marlene Patterer, Alexandra M Nicaise, Stefano Pluchino.
      Multiple sclerosis (MS), a debilitating autoimmune disorder targeting the central nervous system (CNS), is marked by relentless demyelination and inflammation. Clinically, it presents in three distinct forms: relapsing-remitting MS (RRMS), primary progressive MS (PPMS), and secondary progressive MS (SPMS). While disease-modifying therapies (DMTs) offer some relief to people with RRMS, treatment options for progressive MS (pMS) remain frustratingly inadequate. This gap highlights an urgent need for advanced disease modeling techniques to unravel the intricate pathology of pMS. Human induced pluripotent stem cell (iPSC) technologies and brain organoids are emerging as promising tools for disease modeling in both 2D and 3D in vitro environments. These innovative approaches enable the study of disease mechanisms that closely mimic human pathophysiology and offer new platforms for screening therapeutic compounds, surpassing the limitations of traditional animal models. However, deploying brain organoids in disease modeling presents challenges, especially in the context of non-monogenic disorders. This review delves into cutting-edge brain organoid techniques that hold the potential to revolutionize our understanding of pMS, offering a pathway to disentangle its underlying mechanisms and drive transformative discoveries.
    Keywords:  brain organoids; disease modeling; neuroimmunology; precision medicine; progressive multiple sclerosis; regenerative neuroimmunology; smoldering inflammation; stem cells
    DOI:  https://doi.org/10.3389/fncel.2024.1488691
  20. Nat Commun. 2025 Jan 02. 16(1): 300
    OSP-1 protects neurons from autophagic cell death induced by acute oxidative stress.
    Alessandra Donato, Fiona K Ritchie, Lachlan Lu, Mehershad Wadia, Ramon Martinez-Marmol, Eva Kaulich, Kornraviya Sankorrakul, Hang Lu, Sean Coakley, Elizabeth J Coulson, Massimo A Hilliard.
      Oxidative stress, caused by the accumulation of reactive oxygen species (ROS), is a pathological factor in several incurable neurodegenerative conditions as well as in stroke. However, our knowledge of the genetic elements that can be manipulated to protect neurons from oxidative stress-induced cell death is still very limited. Here, using Caenorhabditis elegans as a model system, combined with the optogenetic tool KillerRed to spatially and temporally control ROS generation, we identify a previously uncharacterized gene, oxidative stress protective 1 (osp-1), that protects C. elegans neurons from oxidative damage. Using rodent and human cell cultures, we also show that the protective effect of OSP-1 extends to mammalian cells. Moreover, we demonstrate that OSP-1 functions in a strictly cell-autonomous fashion, and that it localizes to the endoplasmic reticulum (ER) where it has an ER-remodeling function. Finally, we present evidence suggesting that OSP-1 may exert its neuroprotective function by influencing autophagy. Our results point to a potential role of OSP-1 in modulating autophagy, and suggest that overactivation of this cellular process could contribute to neuronal death triggered by oxidative damage.
    DOI:  https://doi.org/10.1038/s41467-024-55105-0
This page is being maintained by Thomas Krichel. It was last updated on 2025‒01‒14 at 16:41.