bims-axbals 2024-01-28 papers

bims-axbals

Biomed News

on Axonal Biology and ALS

Issue of 2024‒01‒28
thirty-six papers selected by
TJ Krzystek, ALS Therapy Development Institute

Mis-spliced transcripts generate de novo proteins in TDP-43-related ALS/FTD.
Nuclear-import receptors as gatekeepers of pathological phase transitions in ALS/FTD.
Emerging perspectives of synaptic biomarkers in ALS and FTD.
A fluid biomarker reveals loss of TDP-43 splicing repression in presymptomatic ALS-FTD.
Fluid biomarkers for amyotrophic lateral sclerosis: a review.
A Panel of miRNA Biomarkers Common to Serum and Brain-Derived Extracellular Vesicles Identified in Mouse Model of Amyotrophic Lateral Sclerosis.
Beyond C9orf72: repeat expansions and copy number variations as risk factors of amyotrophic lateral sclerosis across various populations.
Scalable, optically-responsive human neuromuscular junction model reveals convergent mechanisms of synaptic dysfunction in familial ALS.
TDP-43 pathology links innate and adaptive immunity in amyotrophic lateral sclerosis.
ALS' Perfect Storm: C9orf72-Associated Toxic Dipeptide Repeats as Potential Multipotent Disruptors of Protein Homeostasis.
Precision Medicine in Parkinson's Disease using Induced Pluripotent Stem Cells.
ICA-27243 improves neuromuscular function and preserves motoneurons in the transgenic SOD1G93A mice.
The Multifaceted Role of Cofilin in Neurodegeneration and Stroke: Insights into Pathogenesis and Targeting as a Therapy.
Treatment with sodium butyrate induces autophagy resulting in therapeutic benefits for spinocerebellar ataxia type 3.
A Machine Learning Approach for Highlighting microRNAs as Biomarkers Linked to Amyotrophic Lateral Sclerosis Diagnosis and Progression.
Axonal Lysosomal Assays for Characterizing the Effects of LRRK2 G2019S.
Dietary NMN supplementation enhances motor and NMJ function in ALS.
Caspase-dependent apoptosis in Ribloflavin transporter deficiency iPSCs and derived motor neurons.
Human Pluripotent Stem Cell-Derived Retinal Organoids: A Viable Platform for Investigating the Efficacy of Adeno-Associated Virus Gene Therapy.
Mitochondrial CISD1/Cisd accumulation blocks mitophagy and genetic or pharmacological inhibition rescues neurodegenerative phenotypes in Pink1/parkin models.
Identification and characterization of novel ERBB4 variant associated with sporadic amyotrophic lateral sclerosis (ALS).
Autophagy in spinal muscular atrophy: from pathogenic mechanisms to therapeutic approaches.
The glymphatic system and Amyotrophic lateral sclerosis.
Editorial: Molecular mechanisms underlying C9orf72 neurodegeneration, volume II.
Perry Disease: Bench to Bedside Circulation and a Team Approach.
The SMA Modifier Plastin 3 Targets Cell Membrane-Associated Proteins in Motoneurons.
TDP-43 and Alzheimer's Disease Pathology in the Brain of a Harbor Porpoise Exposed to the Cyanobacterial Toxin BMAA.
Motion of VAPB molecules reveals ER-mitochondria contact site subdomains.
The Promise and Potential of Brain Organoids.
Using an expanded algorithm to estimate prevalence of amyotrophic lateral sclerosis in U.S. and UK.
DNA methylome, R-loop and clinical exome profiling of patients with sporadic amyotrophic lateral sclerosis.
Shared structural features of Miro binding control mitochondrial homeostasis.
Neuronal sensorimotor integration guiding salt concentration navigation in Caenorhabditis elegans.
Protein Quality Control Systems and ER Stress as Key Players in SARS-CoV-2-Induced Neurodegeneration.
Constitutive Endolysosomal Perforation in Neurons allows Induction of α-Synuclein Aggregation by Internalized Pre-Formed Fibrils.
Characterization of a loss-of-function NSF attachment protein beta mutation in monozygotic triplets affected with epilepsy and autism using cortical neurons from proband-derived and CRISPR-corrected induced pluripotent stem cell lines.

Sci Transl Med. 2024 Jan 26. eadg7162

Mis-spliced transcripts generate de novo proteins in TDP-43-related ALS/FTD.

Sahba Seddighi, Yue A Qi, Anna-Leigh Brown, Oscar G Wilkins, Colleen Bereda, Cedric Belair, Yong-Jie Zhang, Mercedes Prudencio, Matthew J Keuss, Aditya Khandeshi, Sarah Pickles, Sarah E Kargbo-Hill, James Hawrot, Daniel M Ramos, Hebao Yuan, Jessica Roberts, Erika Kelmer Sacramento, Syed I Shah, Mike A Nalls, Jennifer M Colón-Mercado, Joel F Reyes, Veronica H Ryan, Matthew P Nelson, Casey N Cook, Ziyi Li, Laurel Screven, Justin Y Kwan, Puja R Mehta, Matteo Zanovello, Martina Hallegger, Anantharaman Shantaraman, Lingyan Ping, Yuka Koike, Björn Oskarsson, Nathan P Staff, Duc M Duong, Aisha Ahmed, Maria Secrier, Jernej Ule, Steven Jacobson, Daniel S Reich, Jonathan D Rohrer, Andrea Malaspina, Dennis W Dickson, Jonathan D Glass, Alessandro Ori, Nicholas T Seyfried, Manolis Maragkakis, Leonard Petrucelli, Pietro Fratta, Michael E Ward.

Functional loss of TDP-43, an RNA-binding protein genetically and pathologically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), leads to inclusion of cryptic exons in hundreds of transcripts during disease. Cryptic exons can promote degradation of affected transcripts, deleteriously altering cellular function through loss-of-function mechanisms. Here, we show that mRNA transcripts harboring cryptic exons generated de novo proteins in TDP-43-depleted human iPSC-derived neurons in vitro, and de novo peptides were found in cerebrospinal fluid (CSF) samples from patients with ALS or FTD. Using coordinated transcriptomic and proteomic studies of TDP-43-depleted human iPSC-derived neurons, we identified 65 peptides that mapped to 12 cryptic exons. Cryptic exons identified in TDP-43-depleted human iPSC-derived neurons were predictive of cryptic exons expressed in postmortem brain tissue from patients with TDP-43 proteinopathy. These cryptic exons produced transcript variants that generated de novo proteins. We discovered that inclusion of cryptic peptide sequences in proteins altered their interactions with other proteins, thereby likely altering their function. Finally, we showed that 18 de novo peptides across 13 genes were present in CSF samples from patients with ALS/FTD spectrum disorders. The demonstration of cryptic exon translation suggests new mechanisms for ALS/FTD pathophysiology downstream of TDP-43 dysfunction and may provide a potential strategy to assay TDP-43 function in patient CSF.

DOI: https://doi.org/10.1126/scitranslmed.adg7162
Mol Neurodegener. 2024 Jan 22. 19(1): 8

Nuclear-import receptors as gatekeepers of pathological phase transitions in ALS/FTD.

Bilal Khalil, Miriam Linsenmeier, Courtney L Smith, James Shorter, Wilfried Rossoll.

  Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative disorders on a disease spectrum that are characterized by the cytoplasmic mislocalization and aberrant phase transitions of prion-like RNA-binding proteins (RBPs). The common accumulation of TAR DNA-binding protein-43 (TDP-43), fused in sarcoma (FUS), and other nuclear RBPs in detergent-insoluble aggregates in the cytoplasm of degenerating neurons in ALS/FTD is connected to nuclear pore dysfunction and other defects in the nucleocytoplasmic transport machinery. Recent advances suggest that beyond their canonical role in the nuclear import of protein cargoes, nuclear-import receptors (NIRs) can prevent and reverse aberrant phase transitions of TDP-43, FUS, and related prion-like RBPs and restore their nuclear localization and function. Here, we showcase the NIR family and how they recognize cargo, drive nuclear import, and chaperone prion-like RBPs linked to ALS/FTD. We also discuss the promise of enhancing NIR levels and developing potentiated NIR variants as therapeutic strategies for ALS/FTD and related neurodegenerative proteinopathies.

Keywords:  Aberrant phase transition; Amyotrophic lateral sclerosis; Chaperone; FUS; Frontotemporal dementia; Importin; Nuclear pore; Nucleocytoplasmic transport; Protein aggregation; RNA-binding proteins; TDP-43

DOI:  https://doi.org/10.1186/s13024-023-00698-1
Front Mol Neurosci. 2023 ;16 1279999

Emerging perspectives of synaptic biomarkers in ALS and FTD.

Karrthik Krishnamurthy, Raj Kumar Pradhan.

  Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD) are debilitating neurodegenerative diseases with shared pathological features like transactive response DNA-binding protein of 43 kDa (TDP-43) inclusions and genetic mutations. Both diseases involve synaptic dysfunction, contributing to their clinical features. Synaptic biomarkers, representing proteins associated with synaptic function or structure, offer insights into disease mechanisms, progression, and treatment responses. These biomarkers can detect disease early, track its progression, and evaluate therapeutic efficacy. ALS is characterized by elevated neurofilament light chain (NfL) levels in cerebrospinal fluid (CSF) and blood, correlating with disease progression. TDP-43 is another key ALS biomarker, its mislocalization linked to synaptic dysfunction. In FTD, TDP-43 and tau proteins are studied as biomarkers. Synaptic biomarkers like neuronal pentraxins (NPs), including neuronal pentraxin 2 (NPTX2), and neuronal pentraxin receptor (NPTXR), offer insights into FTD pathology and cognitive decline. Advanced technologies, like machine learning (ML) and artificial intelligence (AI), aid biomarker discovery and drug development. Challenges in this research include technological limitations in detection, variability across patients, and translating findings from animal models. ML/AI can accelerate discovery by analyzing complex data and predicting disease outcomes. Synaptic biomarkers offer early disease detection, personalized treatment strategies, and insights into disease mechanisms. While challenges persist, technological advancements and interdisciplinary efforts promise to revolutionize the understanding and management of ALS and FTD. This review will explore the present comprehension of synaptic biomarkers in ALS and FTD and discuss their significance and emphasize the prospects and obstacles.

Keywords:  C9orf72; TDP-43; amyotrophic lateral sclerosis; artificial intelligence; frontotemporal dementia; neuronal pentraxin; synaptic biomarkers; synaptic dysfunction

DOI:  https://doi.org/10.3389/fnmol.2023.1279999
Nat Med. 2024 Jan 26.

A fluid biomarker reveals loss of TDP-43 splicing repression in presymptomatic ALS-FTD.

Katherine E Irwin, Pei Jasin, Kerstin E Braunstein, Irika R Sinha, Mark A Garret, Kyra D Bowden, Koping Chang, Juan C Troncoso, Abhay Moghekar, Esther S Oh, Denitza Raitcheva, Dan Bartlett, Timothy Miller, James D Berry, Bryan J Traynor, Jonathan P Ling, Philip C Wong.

Although loss of TAR DNA-binding protein 43 kDa (TDP-43) splicing repression is well documented in postmortem tissues of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), whether this abnormality occurs during early-stage disease remains unresolved. Cryptic exon inclusion reflects loss of function of TDP-43, and thus detection of proteins containing cryptic exon-encoded neoepitopes in cerebrospinal fluid (CSF) or blood could reveal the earliest stages of TDP-43 dysregulation in patients. Here we use a newly characterized monoclonal antibody specific to a TDP-43-dependent cryptic epitope (encoded by the cryptic exon found in HDGFL2) to show that loss of TDP-43 splicing repression occurs in ALS-FTD, including in presymptomatic C9orf72 mutation carriers. Cryptic hepatoma-derived growth factor-like protein 2 (HDGFL2) accumulates in CSF at significantly higher levels in familial ALS-FTD and sporadic ALS compared with controls and is elevated earlier than neurofilament light and phosphorylated neurofilament heavy chain protein levels in familial disease. Cryptic HDGFL2 can also be detected in blood of individuals with ALS-FTD, including in presymptomatic C9orf72 mutation carriers, and accumulates at levels highly correlated with those in CSF. Our findings indicate that loss of TDP-43 cryptic splicing repression occurs early in disease progression, even presymptomatically, and that detection of the HDGFL2 cryptic neoepitope serves as a potential diagnostic biomarker for ALS, which should facilitate patient recruitment and measurement of target engagement in clinical trials.

DOI: https://doi.org/10.1038/s41591-023-02788-5
Mol Neurodegener. 2024 Jan 24. 19(1): 9

Fluid biomarkers for amyotrophic lateral sclerosis: a review.

Katherine E Irwin, Udit Sheth, Philip C Wong, Tania F Gendron.

  Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the loss of upper and lower motor neurons. Presently, three FDA-approved drugs are available to help slow functional decline for patients with ALS, but no cure yet exists. With an average life expectancy of only two to five years after diagnosis, there is a clear need for biomarkers to improve the care of patients with ALS and to expedite ALS treatment development. Here, we provide a review of the efforts made towards identifying diagnostic, prognostic, susceptibility/risk, and response fluid biomarkers with the intent to facilitate a more rapid and accurate ALS diagnosis, to better predict prognosis, to improve clinical trial design, and to inform interpretation of clinical trial results. Over the course of 20 + years, several promising fluid biomarker candidates for ALS have emerged. These will be discussed, as will the exciting new strategies being explored for ALS biomarker discovery and development.

Keywords:  Amyotrophic lateral sclerosis; Cerebrospinal fluid; Clinical trial; Fluid biomarkers; Neurofilament; Plasma; Serum; TDP-43

DOI:  https://doi.org/10.1186/s13024-023-00685-6
Mol Neurobiol. 2024 Jan 22.

A Panel of miRNA Biomarkers Common to Serum and Brain-Derived Extracellular Vesicles Identified in Mouse Model of Amyotrophic Lateral Sclerosis.

Natasha Vassileff, Jereme G Spiers, John D Lee, Trent M Woodruff, Esmaeil Ebrahimie, Manijeh Mohammadi Dehcheshmeh, Andrew F Hill, Lesley Cheng.

  Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disease characterised by the deposition of aggregated proteins including TAR DNA-binding protein 43 (TDP-43) in vulnerable motor neurons and the brain. Extracellular vesicles (EVs) facilitate the spread of neurodegenerative diseases and can be easily accessed in the bloodstream. This study aimed to identify a panel of EV miRNAs that can capture the pathology occurring in the brain and peripheral circulation. EVs were isolated from the cortex (BDEVs) and serum (serum EVs) of 3 month-old and 6-month-old TDP-43*Q331K and TDP-43*WT mice. Following characterisation and miRNA isolation, the EVs underwent next-generation sequencing where 24 differentially packaged miRNAs were identified in the TDP-43*Q331K BDEVs and 7 in the TDP-43*Q331K serum EVs. Several miRNAs, including miR-183-5p, were linked to ALS. Additionally, miR-122-5p and miR-486b-5p were identified in both panels, demonstrating the ability of the serum EVs to capture the dysregulation occurring in the brain. This is the first study to identify miRNAs common to both the serum EVs and BDEVs in a mouse model of ALS.

Keywords:  ALS; Amyotrophic lateral sclerosis; BDEV; Extracellular vesicles; TDP-43; miRNA

DOI:  https://doi.org/10.1007/s12035-023-03857-z
BMC Med Genomics. 2024 Jan 22. 17(1): 30

Beyond C9orf72: repeat expansions and copy number variations as risk factors of amyotrophic lateral sclerosis across various populations.

Zsófia Flóra Nagy, Margit Pál, József I Engelhardt, Mária Judit Molnár, Péter Klivényi, Márta Széll.

  Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder which is characterized by the loss of both upper and lower motor neurons in the central nervous system. In a significant fraction of ALS cases - irrespective of family history- a genetic background may be identified. The genetic background of ALS shows a high variability from one ethnicity to another. The most frequent genetic cause of ALS is the repeat expansion of the C9orf72 gene. With the emergence of next-generation sequencing techniques and copy number alteration calling tools the focus in ALS genetics has shifted from disease causing genes and mutations towards genetic susceptibility and risk factors.In this review we aimed to summarize the most widely recognized and studied ALS linked repeat expansions and copy number variations other than the hexanucleotide repeat expansion in the C9orf72 gene. We compare and contrast their involvement and phenotype modifying roles in ALS among different populations.

Keywords:  ALS; ALS genetics; ATXN1; ATXN2; Amyotrophic lateral sclerosis; Copy number variation; Intermediate length repeat expansion; NIPA1; SMN1; SMN2

DOI:  https://doi.org/10.1186/s12920-024-01807-9
bioRxiv. 2024 Jan 12. pii: 2024.01.11.575304. [Epub ahead of print]

Scalable, optically-responsive human neuromuscular junction model reveals convergent mechanisms of synaptic dysfunction in familial ALS.

Daniel Chen, Polyxeni Philippidou, Bianca de Freitas Brenha, Ashleigh E Schaffer, Helen C Miranda.

Neuromuscular junctions (NMJs) are specialized synapses that mediate communication between motor neurons and skeletal muscles and are essential for movement. The degeneration of this system can lead to symptoms observed in neuromuscular and motor neuron diseases. Studying these synapses and their degeneration has proven challenging. Prior NMJ studies heavily relied upon the use of mouse, chick, or isolated primary human cells, which have demonstrated limited fidelity for disease modeling. To enable the study of NMJ dysfunction and model genetic diseases, we, and others, have developed methods to generate human NMJs from pluripotent stem cells (PSCs), embryonic stem cells, and induced pluripotent stem cells. However, published studies have highlighted technical limitations associated with these complex in vitro NMJ models. In this study, we developed a robust PSC-derived motor neuron and skeletal muscle co-culture method, and demonstrated its sensitivity in modeling motor neuron disease. Our method spontaneously and reproducibly forms human NMJs. We developed multiwell-multielectrode array (MEA) parameters to quantify the activity of PSC-derived skeletal muscles, as well as measured the electrophysiological activity of functional human PSC-derived NMJs. We further leveraged our method to morphologically and functionally assess NMJs from the familial amyotrophic lateral sclerosis (fALS) PSCs, C9orf72 hexanucleotide (G4C2)n repeat expansion (HRE), SOD1 A5V , and TDP43 G298S to define the reproducibility and sensitivity of our system. We observed a significant decrease in the numbers and activity of PSC-derived NMJs developed from the different ALS lines compared to their respective controls. Furthermore, we evaluated a therapeutic candidate undergoing clinical trials and observed a variant-dependent rescue of functionality of NMJs. Our newly developed method provides a platform for the systematic investigation of genetic causes of NMJ neurodegeneration and highlights the need for therapeutic avenues to consider patient genotype.

DOI: https://doi.org/10.1101/2024.01.11.575304
bioRxiv. 2024 Jan 10. pii: 2024.01.07.574541. [Epub ahead of print]

TDP-43 pathology links innate and adaptive immunity in amyotrophic lateral sclerosis.

Baggio A Evangelista, Joey V Ragusa, Kyle Pellegrino, Yija Wu, Ivana Yoseli Quiroga-Barber, Shannon R Cahalan, Omeed K Arooji, Jillann A Madren, Sally Schroeter, Joe Cozzarin, Ling Xie, Xian Chen, Kristen K White, J Ashley Ezzell, Marie A Iannone, Sarah Cohen, Rebecca E Traub, Xiaoyan Li, Richard Bedlack, Douglas H Phanstiel, Rick Meeker, Natalie Stanley, Todd J Cohen.

Amyotrophic lateral sclerosis is the most common fatal motor neuron disease. Approximately 90% of ALS patients exhibit pathology of the master RNA regulator, Transactive Response DNA Binding protein (TDP-43). Despite the prevalence TDP-43 pathology in ALS motor neurons, recent findings suggest immune dysfunction is a determinant of disease progression in patients. Whether TDP-43 pathology elicits disease-modifying immune responses in ALS remains underexplored. In this study, we demonstrate that TDP-43 pathology is internalized by antigen presenting cells, causes vesicle rupture, and leads to innate and adaptive immune cell activation. Using a multiplex imaging platform, we observed interactions between innate and adaptive immune cells near TDP-43 pathological lesions in ALS brain. We used a mass cytometry-based whole-blood stimulation assay to provide evidence that ALS patient peripheral immune cells exhibit responses to TDP-43 aggregates. Taken together, this study provides a novel link between TDP-43 pathology and ALS immune dysfunction, and further highlights the translational and diagnostic implications of monitoring and manipulating the ALS immune response.

DOI: https://doi.org/10.1101/2024.01.07.574541
Cells. 2024 Jan 17. pii: 178. [Epub ahead of print]13(2):

ALS' Perfect Storm: C9orf72-Associated Toxic Dipeptide Repeats as Potential Multipotent Disruptors of Protein Homeostasis.

Paulien H Smeele, Giuliana Cesare, Thomas Vaccari.

  Protein homeostasis is essential for neuron longevity, requiring a balanced regulation between protein synthesis and degradation. The clearance of misfolded and aggregated proteins, mediated by autophagy and the ubiquitin-proteasome systems, maintains protein homeostasis in neurons, which are post-mitotic and thus cannot use cell division to diminish the burden of misfolded proteins. When protein clearance pathways are overwhelmed or otherwise disrupted, the accumulation of misfolded or aggregated proteins can lead to the activation of ER stress and the formation of stress granules, which predominantly attempt to restore the homeostasis by suppressing global protein translation. Alterations in these processes have been widely reported among studies investigating the toxic function of dipeptide repeats (DPRs) produced by G4C2 expansion in the C9orf72 gene of patients with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In this review, we outline the modalities of DPR-induced disruptions in protein homeostasis observed in a wide range of models of C9orf72-linked ALS/FTD. We also discuss the relative importance of each DPR for toxicity, possible synergies between DPRs, and discuss the possible functional relevance of DPR aggregation to disease pathogenesis. Finally, we highlight the interdependencies of the observed effects and reflect on the importance of feedback and feedforward mechanisms in their contribution to disease progression. A better understanding of DPR-associated disease pathogenesis discussed in this review might shed light on disease vulnerabilities that may be amenable with therapeutic interventions.

Keywords:  ALS; C9orf72; ER stress; FTD; autophagy; dipeptide repeats; lysosome; proteasome; protein homeostasis

DOI:  https://doi.org/10.3390/cells13020178
Adv Healthc Mater. 2024 Jan 25. e2303041

Precision Medicine in Parkinson's Disease using Induced Pluripotent Stem Cells.

Min Seong Kim, Hyesoo Kim, Gabsang Lee.

  Parkinson's Disease (PD) is one of the most devastating neurological diseases, however there is no effective cure yet. The availability of human induced pluripotent stem cells (iPSCs) provides unprecedented opportunities to understand the pathogenic mechanism and identification of new therapy for PD. In this review, we will introduce new model system of PD, including two-dimensional (2D) human iPSC-derived midbrain dopaminergic (mDA) neurons, 3D iPSC-derived midbrain organoids (MOs) with cellular complexity, and more advanced microphysiological systems (MPS) with three-dimensional (3D) organoids. We believe that successful integrations and applications of iPSC, organoid, and MPS technologies can bring new insight on PD's pathogenesis that will lead to more effective treatments for this debilitating disease. This article is protectd by copyright. All rights reserved.

Keywords:  Parkinson's disease; induced pluripotent stem cells; microphysiological systems; midbrain organoids

DOI:  https://doi.org/10.1002/adhm.202303041
Neurotherapeutics. 2024 Jan 22. pii: S1878-7479(24)00005-9. [Epub ahead of print]21(2): e00319

ICA-27243 improves neuromuscular function and preserves motoneurons in the transgenic SOD1G93A mice.

Vera M Masegosa, Xavier Navarro, Mireia Herrando-Grabulosa.

  Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the death of upper and lower motor neurons (MNs). Excessive neuronal excitability has been implicated in MN degeneration; thus, modulation of hyperexcitability appears as a promising therapeutic strategy. Potassium channels are attractive targets since they can be activated at subthreshold voltages and can regulate neuronal excitability. In this study, we assayed the effects of N-(6-Chloro-pyridin-3-yl)-3,4-difluorobenzamide compound, known as ICA-27243, as a potential treatment for ALS. ICA-27243 is a highly selective Kv7.2/7.3 opener used mainly in epilepsy models. In the in vitro model of spinal cord organotypic cultures (SCOCs) exposed to acute excitotoxicity, ICA-27243 prevented MN degeneration at a dose-of 10 μM. Administration of ICA-27243 to transgenic SOD1G93A ALS mice improved the decline of neuromuscular function, maintained locomotion and coordination in the rotarod, decreased spinal MN death and attenuated glial reactivity. In conclusion, we report here for the first time that ICA-27243 is an effective treatment for ALS, emphasizing the potential of targeting Kv channels to reduce neuronal hyperexcitability.

Keywords:  Amyotrophic lateral sclerosis; Hyperexcitability; ICA-27243; Motoneuron degeneration; SOD1(G93A) transgenic mice

DOI:  https://doi.org/10.1016/j.neurot.2024.e00319
Cells. 2024 Jan 18. pii: 188. [Epub ahead of print]13(2):

The Multifaceted Role of Cofilin in Neurodegeneration and Stroke: Insights into Pathogenesis and Targeting as a Therapy.

Faheem Shehjar, Daniyah A Almarghalani, Reetika Mahajan, Syed A-M Hasan, Zahoor A Shah.

  This comprehensive review explores the complex role of cofilin, an actin-binding protein, across various neurodegenerative diseases (Alzheimer's, Parkinson's, schizophrenia, amyotrophic lateral sclerosis (ALS), Huntington's) and stroke. Cofilin is an essential protein in cytoskeletal dynamics, and any dysregulation could lead to potentially serious complications. Cofilin's involvement is underscored by its impact on pathological hallmarks like Aβ plaques and α-synuclein aggregates, triggering synaptic dysfunction, dendritic spine loss, and impaired neuronal plasticity, leading to cognitive decline. In Parkinson's disease, cofilin collaborates with α-synuclein, exacerbating neurotoxicity and impairing mitochondrial and axonal function. ALS and frontotemporal dementia showcase cofilin's association with genetic factors like C9ORF72, affecting actin dynamics and contributing to neurotoxicity. Huntington's disease brings cofilin into focus by impairing microglial migration and influencing synaptic plasticity through AMPA receptor regulation. Alzheimer's, Parkinson's, and schizophrenia exhibit 14-3-3 proteins in cofilin dysregulation as a shared pathological mechanism. In the case of stroke, cofilin takes center stage, mediating neurotoxicity and neuronal cell death. Notably, there is a potential overlap in the pathologies and involvement of cofilin in various diseases. In this context, referencing cofilin dysfunction could provide valuable insights into the common pathologies associated with the aforementioned conditions. Moreover, this review explores promising therapeutic interventions, including cofilin inhibitors and gene therapy, demonstrating efficacy in preclinical models. Challenges in inhibitor development, brain delivery, tissue/cell specificity, and long-term safety are acknowledged, emphasizing the need for precision drug therapy. The call to action involves collaborative research, biomarker identification, and advancing translational efforts. Cofilin emerges as a pivotal player, offering potential as a therapeutic target. However, unraveling its complexities requires concerted multidisciplinary efforts for nuanced and effective interventions across the intricate landscape of neurodegenerative diseases and stroke, presenting a hopeful avenue for improved patient care.

Keywords:  cofilin; cofilin inhibition; cofilin signaling; neurodegenerative diseases; neuroinflammation

DOI:  https://doi.org/10.3390/cells13020188
FASEB J. 2024 Jan 31. 38(2): e23429

Treatment with sodium butyrate induces autophagy resulting in therapeutic benefits for spinocerebellar ataxia type 3.

Maxinne Watchon, Katherine J Robinson, Luan Luu, Yousun An, Kristy C Yuan, Stuart K Plenderleith, Flora Cheng, Emily K Don, Garth A Nicholson, Albert Lee, Angela S Laird.

  Spinocerebellar ataxia type 3 (SCA3, also known as Machado Joseph disease) is a fatal neurodegenerative disease caused by the expansion of the trinucleotide repeat region within the ATXN3/MJD gene. Mutation of ATXN3 causes formation of ataxin-3 protein aggregates, neurodegeneration, and motor deficits. Here we investigated the therapeutic potential and mechanistic activity of sodium butyrate (SB), the sodium salt of butyric acid, a metabolite naturally produced by gut microbiota, on cultured SH-SY5Y cells and transgenic zebrafish expressing human ataxin-3 containing 84 glutamine (Q) residues to model SCA3. SCA3 SH-SY5Y cells were found to contain high molecular weight ataxin-3 species and detergent-insoluble protein aggregates. Treatment with SB increased the activity of the autophagy protein quality control pathway in the SCA3 cells, decreased the presence of ataxin-3 aggregates and presence of high molecular weight ataxin-3 in an autophagy-dependent manner. Treatment with SB was also beneficial in vivo, improving swimming performance, increasing activity of the autophagy pathway, and decreasing the presence of insoluble ataxin-3 protein species in the transgenic SCA3 zebrafish. Co-treating the SCA3 zebrafish with SB and chloroquine, an autophagy inhibitor, prevented the beneficial effects of SB on zebrafish swimming, indicating that the improved swimming performance was autophagy-dependent. To understand the mechanism by which SB induces autophagy we performed proteomic analysis of protein lysates from the SB-treated and untreated SCA3 SH-SY5Y cells. We found that SB treatment had increased activity of Protein Kinase A and AMPK signaling, with immunoblot analysis confirming that SB treatment had increased levels of AMPK protein and its substrates. Together our findings indicate that treatment with SB can increase activity of the autophagy pathway process and that this has beneficial effects in vitro and in vivo. While our results suggested that this activity may involve activity of a PKA/AMPK-dependent process, this requires further confirmation. We propose that treatment with sodium butyrate warrants further investigation as a potential treatment for neurodegenerative diseases underpinned by mechanisms relating to protein aggregation including SCA3.

Keywords:  Machado-Joseph disease; autophagy; neurodegeneration; polyQ; sodium butyrate; spinocerebellar ataxia type 3; trinucleotide repeat disease; zebrafish

DOI:  https://doi.org/10.1096/fj.202300963RR
Biomolecules. 2023 Dec 29. pii: 47. [Epub ahead of print]14(1):

A Machine Learning Approach for Highlighting microRNAs as Biomarkers Linked to Amyotrophic Lateral Sclerosis Diagnosis and Progression.

Graziantonio Lauria, Rosita Curcio, Paola Tucci.

  Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive loss of motor neurons in the brain and spinal cord. The early diagnosis of ALS can be challenging, as it usually depends on clinical examination and the exclusion of other possible causes. In this regard, the analysis of miRNA expression profiles in biofluids makes miRNAs promising non-invasive clinical biomarkers. Due to the increasing amount of scientific literature that often provides controversial results, this work aims to deepen the understanding of the current state of the art on this topic using a machine-learning-based approach. A systematic literature search was conducted to analyze a set of 308 scientific articles using the MySLR digital platform and the Latent Dirichlet Allocation (LDA) algorithm. Two relevant topics were identified, and the articles clustered in each of them were analyzed and discussed in terms of biomolecular mechanisms, as well as in translational and clinical settings. Several miRNAs detected in the tissues and biofluids of ALS patients, including blood and cerebrospinal fluid (CSF), have been linked to ALS diagnosis and progression. Some of them may represent promising non-invasive clinical biomarkers. In this context, future scientific priorities and goals have been proposed.

Keywords:  ALS; clinical markers; degenerative diseases; digitalization; miRNAs; prognosis; text mining

DOI:  https://doi.org/10.3390/biom14010047
Biology (Basel). 2024 Jan 20. pii: 58. [Epub ahead of print]13(1):

Axonal Lysosomal Assays for Characterizing the Effects of LRRK2 G2019S.

Priyanka Bhatia, Marc Bickle, Amay A Agrawal, Buster Truss, Aikaterina Nikolaidi, Kathrin Brockmann, Lydia Reinhardt, Stefanie Vogel, Eva M Szegoe, Arun Pal, Andreas Hermann, Ivan Mikicic, Maximina Yun, Björn Falkenburger, Jared Sterneckert.

  The degeneration of axon terminals before the soma, referred to as "dying back", is a feature of Parkinson's disease (PD). Axonal assays are needed to model early PD pathogenesis as well as identify protective therapeutics. We hypothesized that defects in axon lysosomal trafficking as well as injury repair might be important contributing factors to "dying back" pathology in PD. Since primary human PD neurons are inaccessible, we developed assays to quantify axonal trafficking and injury repair using induced pluripotent stem cell (iPSC)-derived neurons with LRRK2 G2019S, which is one of the most common known PD mutations, and isogenic controls. We observed a subtle axonal trafficking phenotype that was partially rescued by a LRRK2 inhibitor. Mutant LRRK2 neurons showed increased phosphorylated Rab10-positive lysosomes, and lysosomal membrane damage increased LRRK2-dependent Rab10 phosphorylation. Neurons with mutant LRRK2 showed a transient increase in lysosomes at axotomy injury sites. This was a pilot study that used two patient-derived lines to develop its methodology; we observed subtle phenotypes that might correlate with heterogeneity in LRRK2-PD patients. Further analysis using additional iPSC lines is needed. Therefore, our axonal lysosomal assays can potentially be used to characterize early PD pathogenesis and test possible therapeutics.

Keywords:  LRRK2; Parkinson’s disease; axonal trafficking; dying back; iPS cells

DOI:  https://doi.org/10.3390/biology13010058
Exp Neurol. 2024 Jan 22. pii: S0014-4886(24)00024-4. [Epub ahead of print]374 114698

Dietary NMN supplementation enhances motor and NMJ function in ALS.

Samuel Lundt, Nannan Zhang, Luis Polo-Parada, Xinglong Wang, Shinghua Ding.

  Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease that causes the degeneration of motor neurons in the motor cortex and spinal cord. Patients with ALS experience muscle weakness and atrophy in the limbs which eventually leads to paralysis and death. NAD+ is critical for energy metabolism, such as glycolysis and oxidative phosphorylation, but is also involved in non-metabolic cellular reactions. In the current study, we determined whether the supplementation of nicotinamide mononucleotide (NMN), an NAD+ precursor, in the diet had beneficial impacts on disease progression using a SOD1G93A mouse model of ALS. We found that the ALS mice fed with an NMN-supplemented diet (ALS+NMN mice) had modestly extended lifespan and exhibited delayed motor dysfunction. Using electrophysiology, we studied the effect of NMN on synaptic transmission at neuromuscular junctions (NMJs) in symptomatic of ALS mice (18 weeks old). ALS+NMN mice had larger end-plate potential (EPP) amplitudes and maintained better responses than ALS mice, and also had restored EPP facilitation. While quantal content was not affected by NMN, miniature EPP (mEPP) amplitude and frequency were elevated in ALS+NMN mice. NMN supplementation in diet also improved NMJ morphology, innervation, mitochondrial structure, and reduced reactive astrogliosis in the ventral horn of the lumbar spinal cord. Overall, our results indicate that dietary consumption of NMN can slow motor impairment, enhance NMJ function and improve healthspan of ALS mice.

Keywords:  ALS; EPP; NAD+; NMN; Neuromuscular junction

DOI:  https://doi.org/10.1016/j.expneurol.2024.114698
Cell Death Discov. 2024 Jan 26. 10(1): 54

Caspase-dependent apoptosis in Ribloflavin transporter deficiency iPSCs and derived motor neurons.

Chiara Marioli, Maurizio Muzzi, Fiorella Colasuonno, Cristian Fiorucci, Nicolò Cicolani, Stefania Petrini, Enrico Bertini, Marco Tartaglia, Claudia Compagnucci, Sandra Moreno.

Riboflavin Transporter Deficiency (RTD) is a rare genetic, childhood-onset disease. This pathology has a relevant neurological involvement, being characterized by motor symptoms, ponto-bulbar paralysis and sensorineural deafness. Such clinical presentation is associated with muscle weakness and motor neuron (MN) degeneration, so that RTD is considered part of the MN disease spectrum. Based on previous findings demonstrating energy dysmetabolism and mitochondrial impairment in RTD induced Pluripotent Stem cells (iPSCs) and iPSC-derived MNs, here we address the involvement of intrinsic apoptotic pathways in disease pathogenesis using these patient-specific in vitro models by combined ultrastructural and confocal analyses. We show impaired neuronal survival of RTD iPSCs and MNs. Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) documents severe alterations in patients' cells, including deranged mitochondrial ultrastructure, and altered plasma membrane and nuclear organization. Occurrence of aberrantly activated apoptosis is confirmed by immunofluorescence and TUNEL assays. Overall, our work provides evidence of a role played by mitochondrial dysfunction in RTD, and identifies neuronal apoptosis as a contributing event in disease pathogenesis, indicating intrinsic apoptosis pathways as possible relevant targets for more effective therapeutical approaches.

DOI: https://doi.org/10.1038/s41420-024-01812-y
Int J Stem Cells. 2024 01 22.

Human Pluripotent Stem Cell-Derived Retinal Organoids: A Viable Platform for Investigating the Efficacy of Adeno-Associated Virus Gene Therapy.

Hyeon-Jin Na, Jae-Eun Kwon, Seung-Hyun Kim, Jiwon Ahn, Ok-Seon Kwon, Kyung-Sook Chung.

  With recent advances in adeno-associated virus (AAV)-based gene therapy, efficacy and toxicity screening have become essential for developing gene therapeutic drugs for retinal diseases. Retinal organoids from human pluripotent stem cells (hPSCs) offer a more accessible and reproducible human test platform for evaluating AAV-based gene therapy. In this study, hPSCs were differentiated into retinal organoids composed of various types of retinal cells. The transduction efficiencies of AAV2 and AAV8, which are widely used in clinical trials of inherited retinal diseases, were analyzed using retinal organoids. These results suggest that retinal organoids derived from hPSCs serve as suitable screening platforms owing to their diverse retinal cell types and similarity to the human retina. In summary, we propose an optimal stepwise protocol that includes the generation of retinal organoids and analysis of AAV transduction efficacy, providing a comprehensive approach for evaluating AAV-based gene therapy for retinal diseases.

Keywords:  Adeno-associated virus; Gene therapy; Organoids; Pluripotent stem cells; Retina

DOI:  https://doi.org/10.15283/ijsc23071
Mol Neurodegener. 2024 Jan 25. 19(1): 12

Mitochondrial CISD1/Cisd accumulation blocks mitophagy and genetic or pharmacological inhibition rescues neurodegenerative phenotypes in Pink1/parkin models.

Aitor Martinez, Alvaro Sanchez-Martinez, Jake T Pickering, Madeleine J Twyning, Ana Terriente-Felix, Po-Lin Chen, Chun-Hong Chen, Alexander J Whitworth.

  BACKGROUND: Mitochondrial dysfunction and toxic protein aggregates have been shown to be key features in the pathogenesis of neurodegenerative diseases, such as Parkinson's disease (PD). Functional analysis of genes linked to PD have revealed that the E3 ligase Parkin and the mitochondrial kinase PINK1 are important factors for mitochondrial quality control. PINK1 phosphorylates and activates Parkin, which in turn ubiquitinates mitochondrial proteins priming them and the mitochondrion itself for degradation. However, it is unclear whether dysregulated mitochondrial degradation or the toxic build-up of certain Parkin ubiquitin substrates is the driving pathophysiological mechanism leading to PD. The iron-sulphur cluster containing proteins CISD1 and CISD2 have been identified as major targets of Parkin in various proteomic studies.METHODS: We employed in vivo Drosophila and human cell culture models to study the role of CISD proteins in cell and tissue viability as well as aged-related neurodegeneration, specifically analysing aspects of mitophagy and autophagy using orthogonal assays.
RESULTS: We show that the Drosophila homolog Cisd accumulates in Pink1 and parkin mutant flies, as well as during ageing. We observed that build-up of Cisd is particularly toxic in neurons, resulting in mitochondrial defects and Ser65-phospho-Ubiquitin accumulation. Age-related increase of Cisd blocks mitophagy and impairs autophagy flux. Importantly, reduction of Cisd levels upregulates mitophagy in vitro and in vivo, and ameliorates pathological phenotypes in locomotion, lifespan and neurodegeneration in Pink1/parkin mutant flies. In addition, we show that pharmacological inhibition of CISD1/2 by rosiglitazone and NL-1 induces mitophagy in human cells and ameliorates the defective phenotypes of Pink1/parkin mutants.
CONCLUSION: Altogether, our studies indicate that Cisd accumulation during ageing and in Pink1/parkin mutants is a key driver of pathology by blocking mitophagy, and genetically and pharmacologically inhibiting CISD proteins may offer a potential target for therapeutic intervention.

Keywords:  Ageing; Autophagy; CISD1; CISD2; Cisd; Mitochondria; Mitophagy; Neurodegeneration; PINK1; Parkin; Parkinson’s disease

DOI:  https://doi.org/10.1186/s13024-024-00701-3
J Neurol Sci. 2024 Jan 13. pii: S0022-510X(24)00020-0. [Epub ahead of print] 122885

Identification and characterization of novel ERBB4 variant associated with sporadic amyotrophic lateral sclerosis (ALS).

Younghwi Kwon, Minsung Kang, Yu-Mi Jeon, Shinrye Lee, Ho-Won Lee, Jin-Sung Park, Hyung-Jun Kim.

  Amyotrophic Lateral Sclerosis (ALS) is the most common type of motor neuron disease characterized by progressive motor neuron degeneration in brain and spinal cord. Most cases are sporadic in ALS and 5-10% of cases are familiar. >50 genes are known to be associated with ALS and one of them is ERBB4. In this paper, we report the case of a 53-year-old ALS patient with progressive muscle weakness and fasciculation, but he had no cognitive decline. We performed the next generation sequencing (NGS) and in silico analysis, it predicted a highly pathogenic variant, c.2116 A > G, p.Asn706Asp (N706D) in the ERBB4 gene. The amino acid residue is highly conserved among species. ERBB4 is a member of the ERBB family of receptor tyrosine kinases. ERBB4 has multiple tyrosine phosphorylation sites, including an autophosphorylation site at tyrosine 1284 residue. Autophosphorylation of ERBB4 promotes biological activity and it associated with NRG-1/ERBB4 pathway. It is already known that tyrosine 128 phosphorylation of ERBB4 is decreased in patients who have ALS-associated ERBB4 mutations. We generated ERBB4 N706D construct using site-directed mutagenesis and checked the phosphorylation level of ERBB4 N706D in NSC-34 cells. We found that the phosphorylation of ERBB4 N706D was decreased compared to ERBB4 wild-type, indicating a loss of function mutation in ERBB4. We report a novel variant in ERBB4 gene leading to ALS through dysfunction of ERBB4.

Keywords:  Amyotrophic lateral sclerosis; ERBB4 N706D; Next generation sequencing

DOI:  https://doi.org/10.1016/j.jns.2024.122885
Front Cell Neurosci. 2023 ;17 1307636

Autophagy in spinal muscular atrophy: from pathogenic mechanisms to therapeutic approaches.

Saman Rashid, Maria Dimitriadi.

  Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder caused by the depletion of the ubiquitously expressed survival motor neuron (SMN) protein. While the genetic cause of SMA has been well documented, the exact mechanism(s) by which SMN depletion results in disease progression remain elusive. A wide body of evidence has highlighted the involvement and dysregulation of autophagy in SMA. Autophagy is a highly conserved lysosomal degradation process which is necessary for cellular homeostasis; defects in the autophagic machinery have been linked with a wide range of neurodegenerative disorders, including amyotrophic lateral sclerosis, Alzheimer's disease and Parkinson's disease. The pathway is particularly known to prevent neurodegeneration and has been suggested to act as a neuroprotective factor, thus presenting an attractive target for novel therapies for SMA patients. In this review, (a) we provide for the first time a comprehensive summary of the perturbations in the autophagic networks that characterize SMA development, (b) highlight the autophagic regulators which may play a key role in SMA pathogenesis and (c) propose decreased autophagic flux as the causative agent underlying the autophagic dysregulation observed in these patients.

Keywords:  autophagic flux; autophagy; macroautophagy; mitophagy; spinal muscular atrophy

DOI:  https://doi.org/10.3389/fncel.2023.1307636
Prog Neurobiol. 2024 Jan 22. pii: S0301-0082(24)00007-8. [Epub ahead of print]234 102571

The glymphatic system and Amyotrophic lateral sclerosis.

Andrew Eisen, Maiken Nedergaard, Emma Gray, Matthew C Kiernan.

  The glymphatic system and the meningeal lymphatic vessels provide a pathway for transport of solutes and clearance of toxic material from the brain. Of specific relevance to ALS, this is applicable for TDP-43 and glutamate, both major elements in disease pathogenesis. Flow is propelled by arterial pulsation, respiration, posture, as well as the positioning and proportion of aquaporin-4 channels (AQP4). Non-REM slow wave sleep is the is key to glymphatic drainage which discontinues during wakefulness. In Parkinson's disease and Alzheimer's disease, sleep impairment is known to predate the development of characteristic clinical features by several years and is associated with progressive accumulation of toxic proteinaceous products. While sleep issues are well described in ALS, consideration of preclinical sleep impairment or the potential of a failing glymphatic system in ALS has rarely been considered. Here we review how the glymphatic system may impact ALS. Preclinical sleep impairment as an unrecognized major risk factor for ALS is considered, while potential therapeutic options to improve glymphatic flow are explored.

Keywords:  Amyotrophic lateral sclerosis; Epidemiology; Glymphatic system; Neurodegeneration; Sleep

DOI:  https://doi.org/10.1016/j.pneurobio.2024.102571
Front Cell Neurosci. 2023 ;17 1357319

Editorial: Molecular mechanisms underlying C9orf72 neurodegeneration, volume II.

Jean-Marc Gallo, Agnes Nishimura, Annakaisa Haapasalo.



Keywords:  C9orf72; amyotrophic lateral sclerosis; autophagy; frontotemporal dementia; neurodegeneration; nucleocytoplasmic transport; small GTPases; telomere

DOI:  https://doi.org/10.3389/fncel.2023.1357319
Biomedicines. 2024 Jan 05. pii: 113. [Epub ahead of print]12(1):

Perry Disease: Bench to Bedside Circulation and a Team Approach.

Takayasu Mishima, Junichi Yuasa-Kawada, Shinsuke Fujioka, Yoshio Tsuboi.

  With technological applications, especially in genetic testing, new diseases have been discovered and new disease concepts have been proposed in recent years; however, the pathogenesis and treatment of these rare diseases are not as well established as those of common diseases. To demonstrate the importance of rare disease research, in this paper we focus on our research topic, Perry disease (Perry syndrome). Perry disease is a rare autosomal dominant neurodegenerative disorder clinically characterized by parkinsonism, depression/apathy, weight loss, and respiratory symptoms including central hypoventilation and central sleep apnea. The pathological classification of Perry disease falls under TAR DNA-binding protein 43 (TDP-43) proteinopathies. Patients with Perry disease exhibit DCTN1 mutations, which is the causative gene for the disease; they also show relatively uniform pathological and clinical features. This review summarizes recent findings regarding Perry disease from both basic and clinical perspectives. In addition, we describe technological innovations and outline future challenges and treatment prospects. We discuss the expansion of research from rare diseases to common diseases and the importance of collaboration between clinicians and researchers. Here, we highlight the importance of researching rare diseases as it contributes to a deeper understanding of more common diseases, thereby opening up new avenues for scientific exploration.

Keywords:  Perry syndrome; bedside; common disease; genetic testing; pathogenesis; rare disease; research; team; technological applications; treatment

DOI:  https://doi.org/10.3390/biomedicines12010113
Neurosci Insights. 2024 ;19 26331055241226623

The SMA Modifier Plastin 3 Targets Cell Membrane-Associated Proteins in Motoneurons.

Sibylle Jablonka, Natascha Schäfer.

  Loss of the Survival Motor Neuron (SMN) gene inevitably leads to spinal muscular atrophy (SMA), one of the most common fatal neuromuscular diseases in children with FDA and EMA approved therapies. However, the cellular mechanisms leading to neuromuscular junction (NMJ) dysfunction due to impaired Ca2+ homeostasis in the presynaptic compartment remain largely unexplained. In the last decade, the so-called SMA modifiers have gained attention. The F-actin bundler Plastin 3 (PLS3) is one of them and counteracts neurotransmission defects, including altered vesicle endocytosis, in Smn-deficient NMJs. Properly bundled F-actin is the basis for the translocation and arrangement of transmembrane proteins at the cell surface. Our recently published data by Hennlein et al., J Cell Biol. (2023) clearly showed that Smn deficiency impairs the F-actin dependent translocation of the high-affinity BDNF receptor TrkB to the cell surface resulting in reduced BDNF-mediated TrkB activation in motor axon terminals. Strikingly, the overexpression of PLS3 restores TrkB availability, and significantly improves the clustering of the active zone-associated voltage-gated calcium channel Cav2.2 in growth cones of Smn-deficient motoneurons. These observations raise the question of how PLS3 mediates the proper cell surface localization and cluster-like formation of Cav2.2 in motor axon terminals.

Keywords:  3D cell culture; BDNF/TrkB; Cacna2d2; Cav2.2; Plastin 3; motoneuron; spinal muscular atrophy

DOI:  https://doi.org/10.1177/26331055241226623
Toxins (Basel). 2024 Jan 12. pii: 42. [Epub ahead of print]16(1):

TDP-43 and Alzheimer's Disease Pathology in the Brain of a Harbor Porpoise Exposed to the Cyanobacterial Toxin BMAA.

Susanna P Garamszegi, Daniel J Brzostowicki, Thomas M Coyne, Regina T Vontell, David A Davis.

  Cetaceans are well-regarded as sentinels for toxin exposure. Emerging studies suggest that cetaceans can also develop neuropathological changes associated with neurodegenerative disease. The occurrence of neuropathology makes cetaceans an ideal species for examining the impact of marine toxins on the brain across the lifespan. Here, we describe TAR DNA-binding protein 43 (TDP-43) proteinopathy and Alzheimer's disease (AD) neuropathological changes in a beached harbor porpoise (Phocoena phocoena) that was exposed to a toxin produced by cyanobacteria called β-N-methylamino-L-alanine (BMAA). We found pathogenic TDP-43 cytoplasmic inclusions in neurons throughout the cerebral cortex, midbrain and brainstem. P62/sequestosome-1, responsible for the autophagy of misfolded proteins, was observed in the amygdala, hippocampus and frontal cortex. Genes implicated in AD and TDP-43 neuropathology such as APP and TARDBP were expressed in the brain. AD neuropathological changes such as amyloid-β plaques, neurofibrillary tangles, granulovacuolar degeneration and Hirano bodies were present in the hippocampus. These findings further support the development of progressive neurodegenerative disease in cetaceans and a potential causative link to cyanobacterial toxins. Climate change, nutrient pollution and industrial waste are increasing the frequency of harmful cyanobacterial blooms. Cyanotoxins like BMAA that are associated with neurodegenerative disease pose an increasing public health risk.

Keywords:  Guam ALS/PDC; blue green algae bloom; cetacean stranding; marine food web; marine neurotoxin; toothed whales

DOI:  https://doi.org/10.3390/toxins16010042
Nature. 2024 Jan 24.

Motion of VAPB molecules reveals ER-mitochondria contact site subdomains.

Christopher J Obara, Jonathon Nixon-Abell, Andrew S Moore, Federica Riccio, David P Hoffman, Gleb Shtengel, C Shan Xu, Kathy Schaefer, H Amalia Pasolli, Jean-Baptiste Masson, Harald F Hess, Christopher P Calderon, Craig Blackstone, Jennifer Lippincott-Schwartz.

To coordinate cellular physiology, eukaryotic cells rely on the rapid exchange of molecules at specialized organelle-organelle contact sites1,2. Endoplasmic reticulum-mitochondrial contact sites (ERMCSs) are particularly vital communication hubs, playing key roles in the exchange of signalling molecules, lipids and metabolites3,4. ERMCSs are maintained by interactions between complementary tethering molecules on the surface of each organelle5,6. However, due to the extreme sensitivity of these membrane interfaces to experimental perturbation7,8, a clear understanding of their nanoscale organization and regulation is still lacking. Here we combine three-dimensional electron microscopy with high-speed molecular tracking of a model organelle tether, Vesicle-associated membrane protein (VAMP)-associated protein B (VAPB), to map the structure and diffusion landscape of ERMCSs. We uncovered dynamic subdomains within VAPB contact sites that correlate with ER membrane curvature and undergo rapid remodelling. We show that VAPB molecules enter and leave ERMCSs within seconds, despite the contact site itself remaining stable over much longer time scales. This metastability allows ERMCSs to remodel with changes in the physiological environment to accommodate metabolic needs of the cell. An amyotrophic lateral sclerosis-associated mutation in VAPB perturbs these subdomains, likely impairing their remodelling capacity and resulting in impaired interorganelle communication. These results establish high-speed single-molecule imaging as a new tool for mapping the structure of contact site interfaces and reveal that the diffusion landscape of VAPB at contact sites is a crucial component of ERMCS homeostasis.

DOI: https://doi.org/10.1038/s41586-023-06956-y
Adv Healthc Mater. 2024 Jan 22. e2302745

The Promise and Potential of Brain Organoids.

Lena Smirnova, Thomas Hartung.

  Brain organoids are three-dimensional in vitro culture systems derived from human pluripotent stem cells that self-organize to model features of the (developing) human brain. This review examines the techniques behind organoid generation, their current and potential applications, and future directions for the field. Brain organoids possess complex architecture containing various neural cell types, synapses, and myelination. They have been utilized for toxicology testing, disease modeling, infection studies, personalized medicine, and gene-environment interaction studies. An emerging concept termed Organoid Intelligence (OI) combines organoids with artificial intelligence systems to generate learning and memory, with the goals of modeling cognition and enabling biological computing applications. Brain organoids allow neuroscience studies not previously achievable with traditional techniques, and have potential to transform disease modeling, drug development, and our understanding of human brain development and disorders. The aspirational vision of OI parallels the origins of artificial intelligence, and efforts are underway to map a roadmap toward its realization. In summary, brain organoids constitute a disruptive technology that is rapidly advancing and gaining traction across multiple disciplines. This article is protected by copyright. All rights reserved.

Keywords:  brain organoid; in vitro model; neurodevelopment; organoid intelligence; personalized medicine

DOI:  https://doi.org/10.1002/adhm.202302745
Neurol Sci. 2024 Jan 25.

Using an expanded algorithm to estimate prevalence of amyotrophic lateral sclerosis in U.S. and UK.

Ali Abbasi, Henrik Fryk, Jan Rudnik, Richard White, Mark Vanderkelen, Anna Scowcroft, Kerina Bonar.

  BACKGROUND: There is an increasing need to better understand the burden of amyotrophic lateral sclerosis (ALS) using real-world data (RWD). However, identifying ALS cases using RWD presents several challenges due to the rarity of ALS and the differences in database coding systems.METHODS: MarketScan claims, and the UK Clinical Practice Research Datalink (CPRD) databases were searched for diagnosis codes of ALS or MND, the only drugs approved for treating ALS (riluzole and edaravone) and clinical visits with 12-month enrolment prior to 1 January 2011. The main algorithm required ≥ 1 ALS diagnosis code together with prescriptions or clinical visits. We expanded the existing algorithm to identify unspecific (possible) ALS group that had codes for motor neuron disease (MND) and the ALS drugs. The study period was from 1 January 2011 until 31 December 2020.
RESULTS: We identified 16,246 patients with ≥ 1 ALS code in Marketscan (denominator n = 85,279,619), yet only 184 were found in the UK CPRD (denominator n = 21,318,589). Using the main algorithm 9,433 ALS patients were included in MarketScan, with a prevalence ranged between 4.5 per 100,000 in 2019 and 6.2 in 2015. In MarketScan, 3,658 (4.3 per 100,000) had ≥ 1 MND code and the ALS drug codes (possible cases). In CPRD, 47.9% of 2,785 patients with ≥ 1 MND code had a prescription for riluzole (6.3 per 100,000), regarded as possible ALS cases.
CONCLUSIONS: The expanded algorithm enabled the identification of a large population with ALS, or possible ALS, and the estimation of ALS prevalence in MarketScan and CPRD.

Keywords:  Algorithm; Amyotrophic lateral sclerosis; Epidemiology; U.S. Claims; UK primary care

DOI:  https://doi.org/10.1007/s10072-024-07336-8
Sci Data. 2024 Jan 24. 11(1): 123

DNA methylome, R-loop and clinical exome profiling of patients with sporadic amyotrophic lateral sclerosis.

Orsolya Feró, Dóra Varga, Éva Nagy, Zsolt Karányi, Éva Sipos, József Engelhardt, Nóra Török, István Balogh, Borbála Vető, István Likó, Ábel Fóthi, Zoltán Szabó, Gábor Halmos, László Vécsei, Tamás Arányi, Lóránt Székvölgyi.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the death of motor neurons, the aetiology of which is essentially unknown. Here, we present an integrative epigenomic study in blood samples from seven clinically characterised sporadic ALS patients to elucidate molecular factors associated with the disease. We used clinical exome sequencing (CES) to study DNA variants, DNA-RNA hybrid immunoprecipitation sequencing (DRIP-seq) to assess R-loop distribution, and reduced representation bisulfite sequencing (RRBS) to examine DNA methylation changes. The above datasets were combined to create a comprehensive repository of genetic and epigenetic changes associated with the ALS cases studied. This repository is well-suited to unveil new correlations within individual patients and across the entire patient cohort. The molecular attributes described here are expected to guide further mechanistic studies on ALS, shedding light on the underlying genetic causes and facilitating the development of new epigenetic therapies to combat this life-threatening disease.

DOI: https://doi.org/10.1038/s41597-024-02985-y
EMBO J. 2024 Jan 24.

Shared structural features of Miro binding control mitochondrial homeostasis.

Christian Covill-Cooke, Brian Kwizera, Guillermo López-Doménech, Caleb Od Thompson, Ngaam J Cheung, Ema Cerezo, Martin Peterka, Josef T Kittler, Benoît Kornmann.

  Miro proteins are universally conserved mitochondrial calcium-binding GTPases that regulate a multitude of mitochondrial processes, including transport, clearance, and lipid trafficking. The exact role of Miro in these functions is unclear but involves binding to a variety of client proteins. How this binding is operated at the molecular level and whether and how it is important for mitochondrial health, however, remains unknown. Here, we show that known Miro interactors-namely, CENPF, Trak, and MYO19-all use a similar short motif to bind the same structural element: a highly conserved hydrophobic pocket in the first calcium-binding domain of Miro. Using these Miro-binding motifs, we identified direct interactors de novo, including MTFR1/2/1L, the lipid transporters Mdm34 and VPS13D, and the ubiquitin E3-ligase Parkin. Given the shared binding mechanism of these functionally diverse clients and its conservation across eukaryotes, we propose that Miro is a universal mitochondrial adaptor coordinating mitochondrial health.

Keywords:  AlphaFold; ERMES; Lipid Transport; Mitophagy; Organelle Transport

DOI:  https://doi.org/10.1038/s44318-024-00028-1
Proc Natl Acad Sci U S A. 2024 Jan 30. 121(5): e2310735121

Neuronal sensorimotor integration guiding salt concentration navigation in Caenorhabditis elegans.

Ayaka Matsumoto, Yu Toyoshima, Chenqi Zhang, Akihiro Isozaki, Keisuke Goda, Yuichi Iino.

  Animals navigate their environment by manipulating their movements and adjusting their trajectory which requires a sophisticated integration of sensory data with their current motor status. Here, we utilize the nematode Caenorhabditis elegans to explore the neural mechanisms of processing the sensory and motor information for navigation. We developed a microfluidic device which allows animals to freely move their heads while receiving temporal NaCl stimuli. We found that C. elegans regulates neck bending direction in response to temporal NaCl concentration changes in a way which is consistent with a C. elegans' navigational strategy which regulates traveling direction toward preferred NaCl concentrations. Our analysis also revealed that the activity of a neck motor neuron is significantly correlated with neck bending and activated by the decrease in NaCl concentration in a phase-dependent manner. By combining the analysis of behavioral and neural response to NaCl stimuli and optogenetic perturbation experiments, we revealed that NaCl decrease during ventral bending activates the neck motor neuron which counteracts ipsilateral bending. Simulations further suggest that this phase-dependent response of neck motor neurons can facilitate curving toward preferred salt concentrations.

Keywords:  behavior; mathematical modeling; navigation; sensorimotor integration

DOI:  https://doi.org/10.1073/pnas.2310735121
Cells. 2024 Jan 09. pii: 123. [Epub ahead of print]13(2):

Protein Quality Control Systems and ER Stress as Key Players in SARS-CoV-2-Induced Neurodegeneration.

Elena Gavilán, Rafael Medina-Guzman, Bazhena Bahatyrevich-Kharitonik, Diego Ruano.

  The COVID-19 pandemic has brought to the forefront the intricate relationship between SARS-CoV-2 and its impact on neurological complications, including potential links to neurodegenerative processes, characterized by a dysfunction of the protein quality control systems and ER stress. This review article explores the role of protein quality control systems, such as the Unfolded Protein Response (UPR), the Endoplasmic Reticulum-Associated Degradation (ERAD), the Ubiquitin-Proteasome System (UPS), autophagy and the molecular chaperones, in SARS-CoV-2 infection. Our hypothesis suggests that SARS-CoV-2 produces ER stress and exploits the protein quality control systems, leading to a disruption in proteostasis that cannot be solved by the host cell. This disruption culminates in cell death and may represent a link between SARS-CoV-2 and neurodegeneration.

Keywords:  COVID-19; ER stress; SARS-CoV-2; neurodegeneration; protein quality control systems

DOI:  https://doi.org/10.3390/cells13020123
bioRxiv. 2024 Jan 01. pii: 2023.12.30.573738. [Epub ahead of print]

Constitutive Endolysosomal Perforation in Neurons allows Induction of α-Synuclein Aggregation by Internalized Pre-Formed Fibrils.

Anwesha Sanyal, Gustavo Scanavachi, Elliott Somerville, Anand Saminathan, Athul Nair, Athanasios Oikonomou, Nikos S Hatzakis, Tom Kirchhausen.

The endocytic pathway is both an essential route of molecular uptake in cells and a potential entry point for pathology-inducing cargo. The cell-to-cell spread of cytotoxic aggregates, such as those of α-synuclein (α-syn) in Parkinson's Disease (PD), exemplifies this duality. Here we used a human iPSC-derived induced neuronal model (iNs) prone to death mediated by aggregation in late endosomes and lysosomes of endogenous α-syn, seeded by internalized pre-formed fibrils of α-syn (PFFs). This PFF-mediated death was not observed with parental iPSCs or other non-neuronal cells. Using live-cell optical microscopy to visualize the read out of biosensors reporting endo-lysosome wounding, we discovered that up to about 10% of late endosomes and lysosomes in iNs exhibited spontaneous constitutive perforations, regardless of the presence of internalized PFFs. This wounding, absent in parental iPSCs and non-neuronal cells, corresponded to partial damage by nanopores in the limiting membranes of a subset of endolysosomes directly observed by volumetric focused ion beam scanning electron microscopy (FIB-SEM) in iNs and in CA1 pyramidal neurons from mouse brain, and not found in iPSCs or in other non-neuronal cells in culture or in mouse liver and skin. We suggest that the compromised limiting membranes in iNs and neurons in general are the primary conduit for cytosolic α-syn to access PFFs entrapped within endo-lysosomal lumens, initiating PFF-mediated α-syn aggregation. Significantly, eradicating the intrinsic endolysosomal perforations in iNs by inhibiting the endosomal Phosphatidylinositol-3-Phosphate/Phosphatidylinositol 5-Kinase (PIKfyve kinase) using Apilimod or Vacuolin-1 markedly reduced PFF-induced α-syn aggregation, despite PFFs continuing to enter the endolysosomal compartment. Crucially, this intervention also diminished iN death associated with PFF incubation. Our results reveal the surprising presence of intrinsically perforated endo-lysosomes in neurons, underscoring their crucial early involvement in the genesis of toxic α-syn aggregates induced by internalized PFFs. This discovery offers a basis for employing PIKfyve kinase inhibition as a potential therapeutic strategy to counteract synucleinopathies.

DOI: https://doi.org/10.1101/2023.12.30.573738
Front Neurosci. 2023 ;17 1302470

Characterization of a loss-of-function NSF attachment protein beta mutation in monozygotic triplets affected with epilepsy and autism using cortical neurons from proband-derived and CRISPR-corrected induced pluripotent stem cell lines.

Gowher Ali, Kyung Chul Shin, Wesal Habbab, Ghaneya Alkhadairi, Alice AbdelAleem, Fouad A AlShaban, Yongsoo Park, Lawrence W Stanton.

  We investigated whether a homozygous recessive genetic variant of NSF attachment protein beta (NAPB) gene inherited by monozygotic triplets contributed to their phenotype of early-onset epilepsy and autism. Induced pluripotent stem cell (iPSC) lines were generated from all three probands and both parents. The NAPB genetic variation was corrected in iPSC lines from two probands by CRISPR/Cas9 gene editing. Cortical neurons were produced by directed, in vitro differentiation from all iPSC lines. These cell line-derived neurons enabled us to determine that the genetic variation in the probands causes exon skipping and complete absence of NAPB protein. Electrophysiological and transcriptomic comparisons of cortical neurons derived from parents and probands cell lines indicate that loss of NAPB function contributes to alterations in neuronal functions and likely contributed to the impaired neurodevelopment of the triplets.

Keywords:  CRISPR/Cas9; NAPB; cortical neuron; exon skipping; iPSC

DOI:  https://doi.org/10.3389/fnins.2023.1302470