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Huntingtons disease (HD) is caused by a CAG repeat expansion in the HTT gene, leading to altered gene expression. However, the mechanisms leading to disrupted RNA processing in HD remain unclear. Here we identify TDP-43 and the N6-methyladenosine (m6A) writer protein METTL3 to be upstream regulators of exon skipping in multiple HD systems. Disrupted nuclear localization of TDP-43 and cytoplasmic accumulation of phosphorylated TDP-43 occurs in HD mouse and human brains, with TDP-43 also co-localizing with HTT nuclear aggregate-like bodies distinct from mutant HTT inclusions. The binding of TDP-43 onto RNAs encoding HD-associated differentially expressed and aberrantly spliced genes is decreased. Finally, m6A RNA modification is reduced on RNAs abnormally expressed in the striatum of HD R6/2 mouse brain, including at clustered sites adjacent to TDP-43 binding sites. Our evidence supports TDP-43 loss of function coupled with altered m6A modification as a mechanism underlying alternative splicing in HD.

Loss of nuclear TDP-43 is a hallmark of neurodegeneration in TDP-43 proteinopathies, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). TDP-43 mislocalization results in cryptic splicing and polyadenylation of pre-messenger RNAs (pre-mRNAs) encoding stathmin-2 (also known as SCG10), a protein that is required for axonal regeneration. We found that TDP-43 binding to a GU-rich region sterically blocked recognition of the cryptic 3 splice site in STMN2 pre-mRNA. Targeting dCasRx or antisense oligonucleotides (ASOs) suppressed cryptic splicing, which restored axonal regeneration and stathmin-2-dependent lysosome trafficking in TDP-43-deficient human motor neurons. In mice that were gene-edited to contain human STMN2 cryptic splice-polyadenylation sequences, ASO injection into cerebral spinal fluid successfully corrected Stmn2 pre-mRNA misprocessing and restored stathmin-2 expression levels independently of TDP-43 binding.

Angelman syndrome is a neurodevelopmental disorder caused by deficiency of the maternally inherited UBE3A gene in neurons. Antisense oligonucleotide therapies are under development to reinstate UBE3A protein production. Non-invasive biomarkers to detect target engagement and treatment response are needed to support clinical trials. Delta power measured in the scalp EEG is a reliable biomarker for Angelman syndrome but varies widely across individuals and throughout development, making detection of a treatment effect using single measurements challenging. We utilized a longitudinal dataset of 204 EEG recordings from 56 subjects with Angelman syndrome to develop a natural history model of delta (2-4 Hz) power, with predictors of age, elapsed time, and relative delta power at an initial recording. Using this model, we computed the sample and effect sizes needed to detect a treatment effect in a human clinical trial with 80% power. We applied the same model structure to a mouse model of Angelman syndrome (n = 41) to detect antisense oligonucleotide-mediated treatment effects on absolute delta activity and Ube3a expression. In humans, delta power at a second time point can be reliably predicted using the natural history model. In mice, a treatment effect can be detected after antisense oligonucleotide treatment targeting the Ube3a-antisense transcript through at least 8 weeks post-treatment (P < 1e-15). Deviations in delta power from the expected natural history correlated with Ube3a expression in the mouse model (P < 0.001). Deviations in delta power from a human natural history model in Angelman syndrome can detect antisense oligonucleotide-mediated improvement in Ube3a expression in Angelman syndrome mice and may be relevant for human clinical trials.

Hexanucleotide expansions in C9ORF72 are the most frequent genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Disease mechanisms were evaluated in mice expressing C9ORF72 RNAs with up to 450 GGGGCC repeats or with one or both C9orf72 alleles inactivated. Chronic 50% reduction of C9ORF72 did not provoke disease, while its absence produced splenomegaly, enlarged lymph nodes, and mild social interaction deficits, but not motor dysfunction. Hexanucleotide expansions caused age-, repeat-length-, and expression-level-dependent accumulation of RNA foci and dipeptide-repeat proteins synthesized by AUG-independent translation, accompanied by loss of hippocampal neurons, increased anxiety, and impaired cognitive function. Single-dose injection of antisense oligonucleotides (ASOs) that target repeat-containing RNAs but preserve levels of mRNAs encoding C9ORF72 produced sustained reductions in RNA foci and dipeptide-repeat proteins, and ameliorated behavioral deficits. These efforts identify gain of toxicity as a central disease mechanism caused by repeat-expanded C9ORF72 and establish the feasibility of ASO-mediated therapy.

We have shown that lithium treatment improves motor coordination in a spinocerebellar ataxia type 1 (SCA1) disease mouse model (Sca1(154Q/+)). To learn more about disease pathogenesis and molecular contributions to the neuroprotective effects of lithium, we investigated metabolomic profiles of cerebellar tissue and plasma from SCA1-model treated and untreated mice. Metabolomic analyses of wild-type and Sca1(154Q/+) mice, with and without lithium treatment, were performed using gas chromatography time-of-flight mass spectrometry and BinBase mass spectral annotations. We detected 416 metabolites, of which 130 were identified. We observed specific metabolic perturbations in Sca1(154Q/+) mice and major effects of lithium on metabolism, centrally and peripherally. Compared to wild-type, Sca1(154Q/+) cerebella metabolic profile revealed changes in glucose, lipids, and metabolites of the tricarboxylic acid cycle and purines. Fewer metabolic differences were noted in Sca1(154Q/+) mouse plasma versus wild-type. In both genotypes, the major lithium responses in cerebellum involved energy metabolism, purines, unsaturated free fatty acids, and aromatic and sulphur-containing amino acids. The largest metabolic difference with lithium was a 10-fold increase in ascorbate levels in wild-type cerebella (p

This article, titled "Theme 04 - In Vivo Experimental Models," was published in the journal Amyotrophic Lateral Sclerosis & Frontotemporal Degeneration. The article features a large number of authors and covers a range of topics related to in vivo experimental models. The authors explore various aspects of these models, including their use in studying amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). The article provides valuable insights into the current research and understanding of these neurodegenerative diseases. [Extracted from the article]

MECP2 Duplication Syndrome (MDS) is a rare, severe neurodevelopmental disorder arising from duplications in the Xq28 region containing the MECP2 gene that predominantly affects males. We generated five human induced pluripotent stem cell (iPSC) lines from the fibroblasts of individuals carrying between 0.355 and 11.2 Mb size duplications in the chromosomal locus containing MECP2. All lines underwent extensive testing to confirm MECP2 duplication and iPSC-related features such as morphology, pluripotency markers, and trilineage differentiation potential. These lines are a valuable resource for molecular and functional studies of MDS as well as screening for a variety of therapeutic approaches. [ABSTRACT FROM AUTHOR]

Recently, a new type of limb-girdle muscular dystrophy (LGMD type 2Z) has been identified due to a missense mutation in POGLUT1 (protein O -glucosyltransferase- Rumi ), an enzyme capable of adding glucose to a distinct serine residue of epidermal growth factor-like repeats containing a C-X-S-X-(P/A)-C consensus sequence such as Notch receptors. Affected patients demonstrate reduced Notch signaling, decreased muscle stem cell pool and hypoglycosylation of α-dystroglycan, leading to LGMD phenotype. Here we report the generation and characterization of an iPSC line (CSCRMi001-A) from a LGMD-2Z patient with missense mutation in POGLUT1 which can be used for in vitro disease modeling. [ABSTRACT FROM AUTHOR]

Background: GRN mutations cause frontotemporal dementia (FTD) due to haploinsufficiency of progranulin. Several microRNAs (miRs), including miR‐29b, have been reported to negatively regulate progranulin protein levels. Here, we tested if antisense oligonucleotides (ASOs) – which are versatile modulators of target mRNA/protein levels – can be used to increase progranulin levels by sterically blocking the miR‐29b binding site. Method: We designed 48 ASOs targeting the miR‐29b binding site in the 3' UTR of the human GRN mRNA. We treated H4 neuroglioma cells and iPSC‐derived neurons with these ASOs and subsequently measured progranulin protein levels by western blot and ELISA. We performed further studies to determine the mechanism of action of these ASOs using ribosomal profiling, metabolic labeling, and FRET assays. Results: We identified 16 ASOs that increased progranulin protein levels in a dose‐dependent manner. Ribosomal profiling experiments revealed that cells treated with ASOs had marked enrichment in GRN mRNA in heavy polyribosome fractions, compared to cells treated with a scrambled control ASO, suggesting that the ASOs increase the rate of progranulin translation. Consistent with this, ASO treatment resulted in increased levels of newly synthesized progranulin protein. FRET‐based assays showed that ASOs can effectively compete miR‐29b from its binding site in the GRN 3' UTR RNA under in vitro conditions. Conclusions: Together, our results demonstrate that ASOs can be used to effectively increase target protein levels by partially blocking miR binding sites. This strategy may be therapeutically feasible for progranulin‐deficient FTD as well as other conditions of haploinsufficiency. [ABSTRACT FROM AUTHOR]

Lateral Meningocele Syndrome (LMS), a disorder associated with NOTCH3 pathogenic variants, presents with neurological, craniofacial and skeletal abnormalities. Mouse models of the disease exhibit osteopenia that is ameliorated by the administration of Notch3 antisense oligonucleotides (ASO) targeting either Notch3 or the Notch3 mutation. To determine the consequences of LMS pathogenic variants in human cells and whether they can be targeted by ASOs, induced pluripotent NCRM1 and NCRM5 stem (iPS) cells harboring a NOTCH36692-93insC insertion were created. Parental iPSCs, NOTCH36692-93insC and isogenic controls, free of chromosomal aberrations as determined by human CytoSNP850 array, were cultured under conditions of neural crest, mesenchymal and osteogenic cell differentiation. The expected cell phenotype was confirmed by surface markers and a decline in OCT3/4 and NANOG mRNA. NOTCH36692-93insC cells displayed enhanced expression of Notch target genes HES1, HEY1, 2 and L demonstrating a NOTCH3 gain-of-function. There was enhanced osteogenesis in NOTCH36692-93insC cells as evidenced by increased mineralized nodule formation and ALPL, BGLAP and BSP expression. ASOs targeting NOTCH3 decreased both NOTCH3 wild type and NOTCH36692-93insC mutant mRNA by 40% in mesenchymal and 90% in osteogenic cells. ASOs targeting the NOTCH3 insertion decreased NOTCH36692-93insC by 70-80% in mesenchymal cells and by 45-55% in osteogenic cells and NOTCH3 mRNA by 15-30% and 20-40%, respectively. In conclusion, a NOTCH3 pathogenic variant causes a modest increase in osteoblastogenesis in human iPS cells in vitro and NOTCH3 and NOTCH3 mutant specific ASOs downregulate NOTCH3 transcripts associated with LMS., Competing Interests: PJ and MC are paid employees of Ionis Pharmaceuticals. Please note that the synthesis and applications of antisense oligonucleotides may be covered by patent(s) filed by Ionis Pharmaceuticals. Individuals wanting to obtain antisense oligonucleotides from Ionis Pharmaceuticals are required to contact Ionis Pharmaceuticals directly. This does not alter our adherence to PLOS ONE policies on sharing data and materials.” as detailed in http://journals.plos.org/plosone/s/competing-interests, (Copyright: © 2025 Canalis et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Pseudoachondroplasia (PSACH), a severe dwarfing condition characterized by impaired skeletal growth and early joint degeneration, results from mutations in cartilage oligomeric matrix protein (COMP). These mutations disrupt normal protein folding, leading to the accumulation of misfolded COMP in chondrocytes. The MT-COMP mouse is a murine model of PSACH that expresses D469del human COMP in response to doxycycline and replicates the PSACH chondrocyte and clinical pathology. The basis for the mutant-COMP pathology involves endoplasmic reticulum (ER) stress signaling through the PERK/eIF2α/CHOP pathway. C/EBP homologous protein (CHOP), in conjunction with a TNFα inflammatory process, upregulates mTORC1, hindering autophagy clearance of mutant COMP protein. Life-long joint pain/degeneration diminishes quality of life, and treatments other than joint replacements are urgently needed. To assess whether molecules that reduce CHOP activity should be considered as a potential treatment for PSACH, we evaluated MT-COMP mice with 50% CHOP (MT-COMP/CHOP +/- ), antisense oligonucleotide (ASO)-mediated CHOP knockdown, and complete CHOP ablation (MT-COMP/CHOP -/- ). While earlier studies demonstrated that loss of CHOP in MT-COMP mice reduced intracellular retention, inflammation, and growth plate chondrocyte death, we now show that it did not normalize limb growth. ASO treatment reduced CHOP mRNA by approximately 60%, as measured by RT-qPCR, but did not improve limb length similar to MT-COMP/CHOP +/- . Interestingly, both 50% genetic reduction and complete loss of CHOP alleviated pain, while total ablation of CHOP in MT-COMP mice was necessary to preserve joint health. These results indicate that (1) CHOP reduction therapy is not an effective strategy for improving limb length and (2) pain and chondrocyte pathology are more responsive to intervention than the prevention of joint damage.

Objective: We aim to explore the role of mechanistic target of rapamycin complex (mTORC) 2 in systemic lupus erythematosus (SLE) development, the in vivo regulation of mTORC2 by type I interferon (IFN) signaling in autoimmunity, and to use mTORC2 targeting therapy to ameliorate lupus-like symptoms in an in vivo lupus mouse model and an in vitro coculture model using human PBMCs., Method: We first induced lupus-like disease in T cell specific Rictor, a key component of mTORC2, deficient mice by topical application of imiquimod (IMQ) and monitored disease development. Next, we investigated the changes of mTORC2 signaling and immunological phenotypes in type I IFNAR deficient Lpr mice. We then tested the beneficial effects of anti-Rictor antisense oligonucleotide (Rictor-ASO) in a mouse model of lupus: MRL/lpr mice. Finally, we examined the beneficial effects of RICTOR-ASO on SLE patients' PBMCs using an in vitro T-B coculture assay., Results: T cell specific Rictor deficient mice have reduced age-associated B cells, plasma cells and germinal center B cells, and less autoantibody production than WT mice following IMQ treatment. IFNAR1 deficient Lpr mice have reduced mTORC2 activity in CD4+ T cells accompanied by restored CD4+ T cell glucose metabolism, partially recovered T cell trafficking, and reduced systemic inflammation. In vivo Rictor-ASO treatment improves renal function and pathology in MRL/lpr mice, along with improved immunopathology. In human SLE (N = 5) PBMCs derived T-B coculture assay, RICTOR-ASO significantly reduce immunoglobulin and autoantibodies production (P < 0.05)., Conclusion: Targeting mTORC2 could be a promising therapeutic for SLE., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Genomic copy-number variations (CNVs) that can cause neurodevelopmental disorders often encompass many genes, which complicates our understanding of how individual genes within a CNV contribute to pathology. MECP2 duplication syndrome (MDS or MRXSL in OMIM; OMIM#300260) is one such CNV disorder caused by duplications spanning methyl CpG-binding protein 2 (MECP2) and other genes on Xq28. Using an antisense oligonucleotide (ASO) to normalize MECP2 dosage is sufficient to rescue abnormal neurological phenotypes in mouse models overexpressing MECP2 alone, implicating the importance of increased MECP2 dosage within CNVs of Xq28. However, because MDS CNVs span MECP2 and additional genes, we generated human neurons from multiple MDS patient-derived induced pluripotent cells (iPSCs) to evaluate the benefit of using an ASO against MECP2 in a MDS human neuronal context. Importantly, we identified a signature of genes that is partially and qualitatively modulated upon ASO treatment, pinpointed genes sensitive to MeCP2 function, and altered in a model of Rett syndrome, a neurological disorder caused by loss of MeCP2 function. Furthermore, the signature contained genes that are aberrantly altered in unaffected control human neurons upon MeCP2 depletion, revealing gene expression programs qualitatively sensitive to MeCP2 levels in human neurons. Lastly, ASO treatment led to a partial rescue of abnormal neuronal morphology in MDS neurons. All together, these data demonstrate that ASOs targeting MECP2 benefit human MDS neurons. Moreover, our study establishes a paradigm by which to evaluate the contribution of individual genes within a CNV to pathogenesis and to assess their potential as a therapeutic target., (© The Author(s) 2024. Published by Oxford University Press.)

The potassium sodium-activated channel subtype T member 1 ( KCNT1 ) gene encodes the Slack channel K Na 1.1, which is expressed in neurons throughout the brain. Gain-of-function variants in KCNT1 are associated with a spectrum of epilepsy syndromes, and mice carrying those variants exhibit a robust phenotype similar to that observed in patients. Kcnt1 knockout (KO) mice, however, have a normal lifespan without any epileptic phenotype. To understand the molecular differences between these two models, we conducted a comprehensive proteomic analysis of the cerebral cortices of Kcnt1 KO and Kcnt1 R455H/+ mice, an animal model bearing a cytoplasmic C-terminal mutation homologous to a human R474H variant that results in EIMFS. The greatest change observed in Kcnt1 KO mice compared to the wild-type mice was the increased expression of multiple proteins of the inner mitochondrial membrane. Electron microscopy studies of cortical mitochondria from Kcnt1 KO mice further confirmed a significant increase in the density of mitochondrial cristae compared to that in wild-type mice. Kcnt1 reduction by a murine-specific Kcnt1 antisense oligonucleotide (ASO) in Kcnt1 R455H/+ mice partially corrected the proteomic dysregulations in the disease model. The results support the hypothesis that ASO-mediated KCNT1 reduction could be therapeutically useful in the treatment of KCNT1 epilepsies.

Protein misfolding and aggregation are cardinal features of neurodegenerative disease (NDD) and they contribute to pathophysiology by both loss-of-function (LOF) and gain-of-function (GOF) mechanisms. This is well exemplified by TDP-43 which aggregates and mislocalizes in several NDDs. The depletion of nuclear TDP-43 leads to reduction in its normal function in RNA metabolism and the cytoplasmic accumulation of TDP-43 leads to aberrant protein homeostasis. A modifier screen found that loss of rad23 suppressed TDP-43 pathology in invertebrate and tissue culture models. Here we show in a mouse model of TDP-43 pathology that genetic or antisense oligonucleotide (ASO)-mediated reduction in rad23a confers benefits on survival and behavior, histological hallmarks of disease and reduction of mislocalized and aggregated TDP-43. This results in improved function of the ubiquitin-proteasome system (UPS) and correction of transcriptomic alterations evoked by pathologic TDP-43. RAD23A-dependent remodeling of the insoluble proteome appears to be a key event driving pathology in this model. As TDP-43 pathology is prevalent in both familial and sporadic NDD, targeting RAD23A may have therapeutic potential.

Background: Hexanucleotide repeat expansion of C9orf72 is a common genetic cause of amyotrophic lateral sclerosis (ALS). No C9orf72-targeted treatments are available. BIIB078 is an investigational antisense oligonucleotide targeting C9orf72 sense RNA. We aimed to assess the safety, tolerability, and pharmacokinetics of BIIB078 in participants with C9orf72-associated ALS., Methods: This phase 1, randomised controlled trial was done at 22 sites in six countries (Canada, Ireland, Netherlands, Switzerland, UK, and USA). Adults with ALS and a pathogenic repeat expansion in C9orf72 were randomly assigned within six cohorts, via Interactive Response Technology in a 3:1 ratio per cohort, to receive BIIB078 (5 mg, 10 mg, 20 mg, 35 mg, 60 mg, or 90 mg in cohorts 1-6, respectively) or placebo, via an intrathecal bolus injection. The treatment period consisted of three loading doses of study treatment, administered approximately once every 2 weeks, followed by monthly maintenance doses during a treatment period of about 3 months for cohorts 1-3 and about 6 months for cohorts 4-6. Patients and investigators were masked to treatment assignment. The primary endpoint was the incidence of adverse events and serious adverse events. This trial was registered with ClinicalTrials.gov (NCT03626012) and is completed., Findings: Between Sept 10, 2018, and Nov 17, 2021, 124 patients were screened for inclusion in the study. 18 patients were excluded and 106 participants were enrolled and randomly assigned to receive 5 mg (n=6), 10 mg (n=9), 20 mg (n=9), 35 mg (n=19), 60 mg (n=18), or 90 mg (n=18) of BIIB078, or placebo (n=27). 58 (55%) of 106 patients were female. All patients received at least one dose of study treatment and were included in all analyses. All participants had at least one adverse event; most adverse events were mild or moderate in severity and did not lead to treatment discontinuation. The most common adverse events in BIIB078-treated participants were falls, procedural pain, headache, and post lumbar puncture syndrome. 14 (18%) of 79 patients who received any dose of BIIB078 reported serious adverse events, compared with nine (33%) of 27 patients who received placebo. Five participants who received BIIB078 and three participants who received placebo had fatal adverse events: respiratory failure in a participant who received 10 mg BIIB078, ALS worsening in two participants who received 35 mg BIIB078, traumatic intracerebral haemorrhage in one participant who received 35 mg BIIB078, pulmonary embolism in one participant who received 60 mg BIIB078, and respiratory failure in three participants who received placebo. All deaths were assessed as not related to the study treatment by the reporting investigator., Interpretation: On the basis of these phase 1 study results, including secondary and exploratory findings showing no reduction in neurofilament levels and no benefit on clinical outcomes relative to the placebo cohort, BIIB078 clinical development has been discontinued. However, these results will be informative in furthering our understanding of the complex pathobiology of C9orf72-associated ALS., Funding: Biogen., Competing Interests: Declaration of interests LHvdB: advisory board for Amylyx, Biogen, Cytokinetics, Denali, QurAlis, Corcept, Novartis, Ferrer, and Sanofi. JDR: advisory board for Expansion Therapeutics and Sanofi and receives support from AbbVie Foundation, ALS Association, ALS Finding a Cure Foundation, American Airlines, Answer ALS Foundation, Aviators Against ALS, Bruce Edwards Foundation, Calico, Caterpillar Foundation, Chan Zuckerberg Initiative, Fishman Family Foundation, F Prime, Glaxo Smith Kline, Microsoft, M Armstrong, Muscular Dystrophy Association, National Football League, National Institutes of Health, Stay, Strong Vs ALS, Team Gleason, The Judith and Jean Pape Adams Charitable Foundation, Travelers Insurance, and the US Department of Defense. PJS: advisory board member for Aclipse Therapeutics, Benevolent AI, Biogen, Bristol Meyers Squibb, Darby Rimmer Foundation, Lilly, Novartis, Quell Therapeutics, QurAlis, Samsara Therapeutics, and Pangea Botanica; receives research support from US Department of Defense, EU Horizon 2020, EU Innovative Medicines Initiative, Fight MND, LifeArc, the Medical Research Council, MND Association, My Name'5 Doddie Foundation, NIHR, Pfizer, Quell Therapeutics, SwanBio, and Wolfson Foundation; and has received support for clinical trials participation from Alexion, Biogen, the EU Horizon programme, and UK NIHR. SB: received research funding from National Institutes of Health, American Academy of Neurology, American Association for Electrodiagnostic and Neuromuscular Medicine (AANEM), Muscular Dystrophy Association, OrphAI Therapeutics, Biogen, Ionis, Medicinova, Novartis, Orion, Voyager Therapeutics, and Denali Therapeutics; honoraria for patient and clinician educational activities related to ALS from AANEM Foundation, McCourt Foundation, and Medscape; institutional consulting or advisory board fees from OrphAI Therapeutics and Biogen; and platform trial coordination centre activities from HEALEY ALS. MB: consultant to Alector, Annexon, Arrowhead, Biogen, Denali, Eli Lilly, Novartis, Roche, Sanofi, UniQure, and Woolsey; clinical trial site investigator for Biogen and Orphazyme; and intellectual property licensed to Biogen and Orphazyme. RCB: advisory board for MT Pharma, has a consulting role with Biogen, has Equity in Neuroquestions LLC, and receives a recurring annual gift from a patient's family for research on neuralgic amyotrophy. AG: ad hoc consultant for genetic testing for Biogen; consultant on ALS trial design for Alexion, AL-S Pharma, Calico, Cytokinetics, and Sanofi; and CMO at QurAlis. JDG: institution was contracted by Biogen as a trial site and was paid for those services; received grants from Muscular Dystrophy Association and National Institutes of Health The Amyotrophic Lateral Sclerosis Association and received commercial sponsorships for clinical trials from Amylyx, Biogen, Cytokinetics, and Neuralstem. OH: funding from Science Foundation Ireland (grants SFI 16/RC/3948 and 20/SP/8953); received consulting fees from Accelsior, Biogen, Cytokinetics, Denali, Novartis, Orion, and Wave Pharmaceuticals; and is Editor-in-Chief of the journal Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration. VL: institution was contracted by Biogen as a trial site and was paid for those services; and Chair of independent data monitoring committee at Vico Therapeutics and member of independent data monitoring committees at QurAlis and Cyclo Therapeutics. TM: consultant to Amylyx, Biogen, Cytokinetics, and QurAlis. BO: serves as a consultant for Columbia University/Tsumura, MediciNova, Biogen, UniQure, Amylyx, and Mitsubishi and has research grants from Columbia University/Tsumura, Biogen, MediciNova, Cytokinetics, Mitsubishi, Calico, Novartis, Sanofi, Ashvattha, and TARGET ALS. GLP: medical advisory roles for Amylyx, Avanir, Biogen, Catalyst, Cytokinetics, MT Pharma, Otsuka, and the US Department of Defense. JR: serves on advisory boards to Libra, Golgi, and Transposon and consultant to Verge, Iris, and Zydus. MW: consultant to Allmiral, Biogen, Mitsubishi Tanabe Pharma, Neuraxpharm, and Novartis. LZ: received honorarium for being on a Biogen advisory board. PJ-n and FR: paid employees of Ionis Pharmaceuticals. LL, DG, MM, JI, SS, SG, and SF: employees of and may hold stock in Biogen. TAF, ALG, and SE: employees of Biogen at the time the study was conducted. CES: declares no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)