A repeat expansion in C9ORF72 causes frontotemporal dementia and amyotrophic lateral sclerosis (c9FTD/ALS). RNA of the expanded repeat (r(GGGGCC)exp) forms nuclear foci or undergoes repeat-associated ...non-ATG (RAN) translation, producing “c9RAN proteins.” Since neutralizing r(GGGGCC)exp could inhibit these potentially toxic events, we sought to identify small-molecule binders of r(GGGGCC)exp. Chemical and enzymatic probing of r(GGGGCC)8 indicate that it adopts a hairpin structure in equilibrium with a quadruplex structure. Using this model, bioactive small molecules targeting r(GGGGCC)exp were designed and found to significantly inhibit RAN translation and foci formation in cultured cells expressing r(GGGGCC)66 and neurons transdifferentiated from fibroblasts of repeat expansion carriers. Finally, we show that poly(GP) c9RAN proteins are specifically detected in c9ALS patient cerebrospinal fluid. Our findings highlight r(GGGGCC)exp-binding small molecules as a possible c9FTD/ALS therapeutic and suggest that c9RAN proteins could potentially serve as a pharmacodynamic biomarker to assess efficacy of therapies that target r(GGGGCC)exp.
•(GGGGCC) RNA forms a hairpin structure in equilibrium with a G-quadruplex structure•Neurons directly converted from C9ORF72+ fibroblasts express c9RAN proteins and foci•Small-molecule binders of (GGGGCC)exp RNA ameliorate c9FTD/ALS-associated defects•c9RAN proteins are detected in c9ALS patient cerebrospinal fluid
A repeat expansion in C9ORF72 causes frontotemporal dementia and amyotrophic lateral sclerosis, presumably via the expression of repeat-containing RNA (r(GGGGCC)exp). Su et al. find that small molecules targeting r(GGGGCC)exp can block c9FTD/ALS-associated defects and reveal a potential biomarker for c9FTD/ALS.
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease of the motor nervous system. We show using multielectrode array and patch-clamp recordings that hyperexcitability detected by ...clinical neurophysiological studies of ALS patients is recapitulated in induced pluripotent stem cell-derived motor neurons from ALS patients harboring superoxide dismutase 1 (SOD1), C9orf72, and fused-in-sarcoma mutations. Motor neurons produced from a genetically corrected but otherwise isogenic SOD1(+/+) stem cell line do not display the hyperexcitability phenotype. SOD1(A4V/+) ALS patient-derived motor neurons have reduced delayed-rectifier potassium current amplitudes relative to control-derived motor neurons, a deficit that may underlie their hyperexcitability. The Kv7 channel activator retigabine both blocks the hyperexcitability and improves motor neuron survival in vitro when tested in SOD1 mutant ALS cases. Therefore, electrophysiological characterization of human stem cell-derived neurons can reveal disease-related mechanisms and identify therapeutic candidates.
The antisense molecule tofersen was tested intrathecally in 108 patients with ALS due to
SOD1
mutations. In a subgroup with faster-progressing disease, there was no clinical difference from placebo ...over a period of 28 weeks.
Summary Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disease that is currently untreatable. Many compounds have been tested in laboratory-based models and in patients with ALS, ...but so far only one drug, riluzole, has shown efficacy, yet it only slightly slows disease progression. Several new insights into the causes of motor neuron death have led to the identification of some important novel targets for intervention. At no time have studies involved such a wide range of innovations and such advanced technologies. Many promising studies are underway to test potential targets that will hopefully translate into meaningful therapeutics for patients with ALS.
Ceftriaxone increases expression of the astrocytic glutamate transporter, EAAT2, which might protect from glutamate-mediated excitotoxicity. A trial using a novel three stage nonstop design, ...incorporating Phases I-III, tested ceftriaxone in ALS. Stage 1 determined the cerebrospinal fluid pharmacokinetics of ceftriaxone in subjects with ALS. Stage 2 evaluated safety and tolerability for 20-weeks. Analysis of the pharmacokinetics, tolerability, and safety was used to determine the ceftriaxone dosage for Stage 3 efficacy testing.
In Stage 1, 66 subjects at ten clinical sites were enrolled and randomized equally into three study groups receiving intravenous placebo, ceftriaxone 2 grams daily or ceftriaxone 4 grams daily divided BID. Participants provided serum and cerebrospinal fluid for pharmacokinetic analysis on study day 7. Participants continued their assigned treatment in Stage 2. The Data and Safety Monitoring Board (DSMB) reviewed the data after the last participants completed 20 weeks on study drug.
Stage 1 analysis revealed linear pharmacokinetics, and CSF trough levels for both dosage levels exceeding the pre-specified target trough level of 1 µM (0.55 µg/mL). Tolerability (Stages 1 and 2) results showed that ceftriaxone at dosages up to 4 grams/day was well tolerated at 20 weeks. Biliary adverse events were more common with ceftriaxone but not dose-dependent and improved with ursodeoxycholic (ursodiol) therapy.
The goals of Stages 1 and 2 of the ceftriaxone trial were successfully achieved. Based on the pre-specified decision rules, the DSMB recommended the use of ceftriaxone 4 g/d (divided BID) for Stage 3, which recently closed.
ClinicalTrials.gov NCT00349622.
Objective
To investigate miR‐155 in the SOD1 mouse model and human sporadic and familial amyotrophic lateral sclerosis (ALS).
Methods
NanoString microRNA, microglia and immune gene profiles, protein ...mass spectrometry, and RNA‐seq analyses were measured in spinal cord microglia, splenic monocytes, and spinal cord tissue from SOD1 mice and in spinal cord tissue of familial and sporadic ALS. miR‐155 was targeted by genetic ablation or by peripheral or centrally administered anti–miR‐155 inhibitor in SOD1 mice.
Results
In SOD1 mice, we found loss of the molecular signature that characterizes homeostatic microglia and increased expression of miR‐155. There was loss of the microglial molecules P2ry12, Tmem119, Olfml3, transcription factors Egr1, Atf3, Jun, Fos, and Mafb, and the upstream regulators Csf1r, Tgfb1, and Tgfbr1, which are essential for microglial survival. Microglia biological functions were suppressed including phagocytosis. Genetic ablation of miR‐155 increased survival in SOD1 mice by 51 days in females and 27 days in males and restored the abnormal microglia and monocyte molecular signatures. Disease severity in SOD1 males was associated with early upregulation of inflammatory genes, including Apoe in microglia. Treatment of adult microglia with apolipoprotein E suppressed the M0‐homeostatic unique microglia signature and induced an M1‐like phenotype. miR‐155 expression was increased in the spinal cord of both familial and sporadic ALS. Dysregulated proteins that we identified in human ALS spinal cord were restored in SOD1G93A/miR‐155−/− mice. Intraventricular anti–miR‐155 treatment derepressed microglial miR‐155 targeted genes, and peripheral anti–miR‐155 treatment prolonged survival.
Interpretation
We found overexpression of miR‐155 in the SOD1 mouse and in both sporadic and familial human ALS. Targeting miR‐155 in SOD1 mice restores dysfunctional microglia and ameliorates disease. These findings identify miR‐155 as a therapeutic target for the treatment of ALS. ANN NEUROL 2015;77:75–99
Summary Background Mutations in SOD1 cause 13% of familial amyotrophic lateral sclerosis. In the SOD1 Gly93Ala rat model of amyotrophic lateral sclerosis, the antisense oligonucleotide ISIS 333611 ...delivered to CSF decreased SOD1 mRNA and protein concentrations in spinal cord tissue and prolonged survival. We aimed to assess the safety, tolerability, and pharmacokinetics of ISIS 333611 after intrathecal administration in patients with SOD1 -related familial amyotrophic lateral sclerosis. Methods In this randomised, placebo-controlled, phase 1 trial, we delivered ISIS 333611 by intrathecal infusion using an external pump over 11·5 h at increasing doses (0·15 mg, 0·50 mg, 1·50 mg, 3·00 mg) to four cohorts of eight patients with SOD1 -positive amyotrophic lateral sclerosis (six patients assigned to ISIS 333611, two to placebo in each cohort). We did the randomisation with a web-based system, assigning patients in blocks of four. Patients and investigators were masked to treatment assignment. Participants were allowed to re-enrol in subsequent cohorts. Our primary objective was to assess the safety and tolerability of ISIS 333611. Assessments were done during infusion and over 28 days after infusion. This study was registered with Clinicaltrials.gov , number NCT01041222. Findings Seven of eight (88%) patients in the placebo group versus 20 of 24 (83%) in the ISIS 333611 group had adverse events. The most common events were post-lumbar puncture syndrome (3/8 38% vs 8/24 33%), back pain (4/8 50% vs 4/24 17%), and nausea (0/8 0% vs 3/24 13%). We recorded no dose-limiting toxic effects or any safety or tolerability concerns related to ISIS 333611. No serious adverse events occurred in patients given ISIS 333611. Re-enrolment and re-treatment were also well tolerated. Interpretation This trial is the first clinical study of intrathecal delivery of an antisense oligonucleotide. ISIS 333611 was well tolerated when administered as an intrathecal infusion. Antisense oligonucleotides delivered to the CNS might be a feasible treatment for neurological disorders. Funding The ALS Association, Muscular Dystrophy Association, Isis Pharmaceuticals.
The SARS-CoV-2 (COVID-19) viral pandemic dramatically affected human health, health care delivery, health care workers, and health care research worldwide. The field of academic neurology was no ...exception. In this 2022 Presidential Plenary, we discuss the challenges faced by neurologists and neuroscientists professionally and personally. We review the threats posed by the pandemic to neuroscience research activities, materials, productivity, and funding. We then discuss the impact of the pandemic on clinical trials for neurologic diseases. Restrictions to patient enrolment due to limited in-person access to laboratory testing, imaging, and study visits led to delay in both clinical trial enrolment and study completion but also to innovative new means to engage clinical trial participants remotely and to strategies to critically appraise the frequency and design of trial-related patient evaluations. Clinical care was also challenged by initial pandemic prioritization of urgent visit and inpatient care and the rapid pivot to telehealth for most other neurology care encounters. Front-line neurology care teams faced their fears of infection, with the first few months of the pandemic being characterized by uncertainty, inconsistent national health care strategies, limited personal protective equipment, and an alarming rate of human illness and death caused by COVID-19. The personal and societal toll of the pandemic is incalculable. Across research and clinical neurology providers, women and particularly those with young families juggled the impossible balance of career and family care as schools closed and children required home-based education. Shining through this dark time are lessons that should shape a brighter future for our field. We are resilient, and the advances in neuroscience and neurology care continue to advance improved neurologic outcomes. The National Institutes of Health devised multiple support strategies for researchers to help bridge the pandemic. Telehealth, clinical trial designs that are more participant-centric with remote monitoring, and flexible work schedules are strategies to rebalance overworked lives and improve our engagement with our patients. As we re-emerge, we have the chance to reframe our field.
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