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Fasudil is a small molecule inhibitor of Rho-associated kinase (ROCK) and is approved for the treatment of subarachnoid haemorrhage. In preclinical studies, fasudil has been shown to attenuate neurodegeneration, modulate neuroinflammation, and foster axonal regeneration. We aimed to investigate the safety, tolerability, and efficacy of fasudil in patients with amyotrophic lateral sclerosis. ROCK-ALS was a phase 2, randomised, double-blind, placebo-controlled trial conducted at 19 amyotrophic lateral sclerosis centres in Germany, France, and Switzerland. Individuals (aged 18–80 years) with at least probable amyotrophic lateral sclerosis (as per the revised El Escorial criteria), a disease duration of 6–24 months, and a slow vital capacity greater than 65% of predicted normal were eligible for inclusion. Patients were randomly assigned (1:1:1) to receive 30 mg (15 mg twice daily) or 60 mg (30 mg twice daily) fasudil or matched placebo intravenously for 20 days over a 4-week period. Follow-up assessments were performed at 45, 90, and 180 days after treatment initiation. The co-primary endpoints were safety until day 180 (defined as the proportion without drug-related serious adverse events) and tolerability during the treatment period (defined as the proportion who did not discontinue treatment due to suspected drug-related adverse events). The primary analyses were carried out in the intention-to-treat population, which included all participants who entered the treatment phase. This trial is registered at ClinicalTrials.gov (NCT03792490) and Eudra-CT (2017-003676-31) and is now completed. Between Feb 20, 2019, and April 20, 2022, 120 participants were enrolled and randomised; two individuals assigned fasudil 30 mg withdrew consent before the baseline visit. Thus, the intention-to-treat population comprised 35 in the fasudil 30 mg group, 39 in the fasudil 60 mg group, and 44 in the placebo group. The estimated proportion without a drug-related serious adverse event was 1·00 (95% CI 0·91 to 1·00) with placebo, 1·00 (0·89 to 1·00) with fasudil 30 mg, and 1·00 (0·90 to 1·00) with fasudil 60 mg; the difference in proportions was 0·00 (95% CI –0·11 to 0·10; p>0·99) for fasudil 30 mg versus placebo and 0·00 (–0·10 to 0·10; p>0·99) for fasudil 60 mg versus placebo. Treatment tolerability (the estimated proportion who did not discontinue) was 0·93 (95% CI 0·81 to 0·99) with placebo, 1·00 (0·90 to 1·00) with fasudil 30 mg, and 0·90 (0·76 to 0·97) with fasudil 60 mg; the difference in proportions was 0·07 (95% CI –0·05 to 0·20; p=0·25) for fasudil 30 mg versus placebo, and –0·03 (–0·18 to 0·10; p=0·70) for fasudil 60 mg versus placebo. Eight deaths occurred: two in the placebo group, four in the fasudil 30 mg group, and two in the fasudil 60 mg group. The most common serious adverse events were respiratory failure (seven events), gastrostomy (five events), pneumonia (four events), and dysphagia (four events). No serious adverse events or deaths were attributed to study treatment. Adverse events, which were mainly related to disease progression, occurred in 139 participants in the placebo group, 108 in the fasudil 30 mg group, and 105 in the fasudil 60 mg group. Fasudil was well tolerated and safe in people with amyotrophic lateral sclerosis. The effect of fasudil on efficacy outcomes should be explored in larger clinical trials with a longer treatment duration, oral administration, and potentially higher dose of the trial drug. Framework of the E-Rare Joint Transnational Call 2016 "Clinical research for new therapeutic uses of already existing molecules (repurposing) in rare diseases". [ABSTRACT FROM AUTHOR]

Motor neuron disease represents a group of progressive and incurable diseases that are characterised by selective loss of motor neurons, resulting in an urgent need for rapid identification of effective disease-modifying therapies. The MND SMART trial aims to test the safety and efficacy of promising interventions efficiently and definitively against a single contemporaneous placebo control group. We now report results of the stage two interim analysis for memantine and trazodone. MND SMART is an investigator-led, phase 3, double-blind, placebo-controlled, multiarm, multistage, randomised, adaptive platform trial recruiting at 20 hospital centres in the UK. Individuals older than 18 years with a confirmed diagnosis of either amyotrophic lateral sclerosis classified by the revised El Escorial criteria, primary lateral sclerosis, progressive muscular atrophy, or progressive bulbar palsy, regardless of disease duration, were eligible for screening. Participants were randomised (1:1:1) to receive oral trazodone 200 mg once a day, oral memantine 20 mg once a day, or matched placebo using a computer-generated minimisation algorithm delivered via a secure web-based system. Co-primary outcome measures were clinical functioning, measured by rate of change in the Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (ALSFRS-R), and survival. Comparisons were conducted in four stages, with predefined criteria for stopping at the end of stages one and two. We report interim analysis from the stage two results, which was done when 100 participants per group (excluding long survivors, defined as >8 years since diagnosis at baseline) completed a minimum of 12 months of follow-up for the candidate investigational medicinal products. The trial is registered on the European Clinical Trials Registry, 2019–000099–41, and ClinicalTrials.gov , NCT04302870 , and is ongoing. Between Feb 27, 2020, and July 24, 2023 (database lock for interim analysis two), 554 people with a motor neuron disease were randomly allocated to memantine (183 [33%]), trazodone (185 [33%]), or placebo (186 [34%]). The primary interim analysis population comprised 530 participants, of whom 175 (33%) had been allocated memantine, 175 (33%) had been allocated trazodone, and 180 (34%) had been allocated placebo. Over 12 months of follow-up, the mean rate of change per month in ALSFRS-R was –0·650 for memantine, –0·625 for trazodone, and –0·655 for placebo (memantine versus placebo estimated mean difference 0·033, one-sided 90% CI lower level –0·085; one-sided p=0·36; trazodone vs placebo: 0·065, –0·051; one-sided p=0·24). The one-sided p values were both above the significance threshold of 10%, indicating that neither memantine nor trazodone groups met the criteria for continuation. There were 483 participants with at least one adverse event (145 [77%] on placebo, 170 [91%] on memantine, and 168 [90%] on trazodone). There were 88 participants with at least one serious adverse event (37 [20%] on memantine, 27 [14%] on trazodone, and 24 [13%] on placebo). A total of 11 serious adverse event led to treatment discontinuation. There was no survival difference between comparisons, with 49 deaths in the memantine group, 52 deaths in the trazodone group, and 48 deaths in the placebo group. Neither memantine nor trazodone improved efficacy outcomes compared with placebo. This result is sufficiently powered to warrant no further testing of trazodone or memantine in motor neuron disease at the doses evaluated in this study. The multiarm multistage design shows important benefits in reducing the time, cost, and participant numbers to reach a definitive result. The Euan MacDonald Centre, MND Scotland, My Name'5 Doddie Foundation, and Baillie Gifford. [ABSTRACT FROM AUTHOR]

The ability to mount an interferon-mediated innate immune response is essential in protection against neurotropic viruses, but antiviral type I interferons also have neurotoxic potential. The production of type I interferons can be triggered by self-derived nucleic acids, and the brain can be susceptible to inappropriate upregulation of type I interferon signalling. Homoeostatic dysregulation of type I interferons has been implicated in rare inborn errors of immunity (referred to as type I interferonopathies) and more common neurodegenerative disorders (eg, Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis). Recent developments include new insights into the pathogenesis of these disorders that involve dysregulated type I interferon signalling, as well as advances in their diagnosis and management. The role of type I interferons in brain cellular health suggests the future therapeutic potential of approaches that target these interferons and their signalling. [ABSTRACT FROM AUTHOR]

Dyspnea, the subjective sensation of breathlessness, is a distressing and potentially traumatic symptom. Dyspnea associated with mechanical ventilation may contribute to intensive care unit (ICU) associated post-traumatic stress disorder and impaired quality of life. Dyspnea is both difficult to alleviate and a cause of significant distress to patients, their loved ones, and care providers People living with neuromuscular disease, such as amyotrophic lateral sclerosis (ALS) or myasthenia gravis (MG), often rely on a ventilator at late stages of illness due to complications of progressive respiratory muscle weakness and paralysis. When unable to wean from the ventilator, conversations turn towards goals of care and release from the ventilator for comfort and end of life (EOL). Patients with and without neuromuscular disease have high risk for dyspnea at EOL upon ventilator liberation. Although limited recommendations have been published specific to patients with ALS, no guidelines currently exist for the terminal liberation from mechanical ventilation in patients experiencing respiratory muscle insufficiency from a neuromuscular disease. Further research on this topic is needed, including creation of a protocol for ventilator release in patients with neuromuscular disease. The following case reports detail the dissimilar EOL experiences of two patients with different forms of neuromuscular disease. [ABSTRACT FROM AUTHOR]

In 2021, the US Congress passed the Accelerating Access to Critical Therapies for Amyotrophic Lateral Sclerosis Act. The law encourages development of "tools, methods, and processes" to improve clinical trial efficiency for neurodegenerative diseases. The Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) is an outcome measure administered during in-person clinic visits and used to support investigational studies for persons living with amyotrophic lateral sclerosis. Availability of a standardized, remote-use version of the ALSFRS-R may promote more inclusive, decentralized clinical trials. A scoping literature review was conducted to identify existing remote-use ALSFRS-R tools, synthesize feasibility and comparability of administration modes, and summarize barriers and facilitators to inform development of a standardized remote-use ALSFRS-R tool. Included studies reported comparisons between remote and in-person, clinician-reported, ALSFRS-R administration and were published in English (2002-2022). References were identified by searching peer-reviewed and gray literature. Twelve studies met the inclusion criteria and were analyzed to compare findings within and across modes of administration. Remote modes of ALSFRS-R administration were categorized into 4 nonmutually exclusive categories: telephone (n = 6), videoconferencing (n = 3), computer or online platforms (n = 3), mobile applications and wearables (n = 2), and 1 unspecified telemedicine modality (n = 1). Studies comparing in-person to telephone or videoconferencing administration reported high ALSFRS-R rating correlations and nonsignificant between-mode differences. There is insufficient information in the ALSFRS-R literature to support remote clinician administration for collecting high quality data. Future research should engage persons living with amyotrophic lateral sclerosis, care partners, and providers to develop a standardized remote-use ALSFRS-R version. • Telephone and videoconferencing modalities have shown promise as platforms for conducting clinical outcome assessments remotely. The Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) is a commonly used clinical outcome assessments tool in investigative clinical trials for ALS, but no single, standardized, remote administration of the paper ALSFRS-R was identified in this review. • Limited psychometric data in support of remote modalities are reported in the evaluated literature including some indications of moderate reliability between modalites. Additionally, the ALSFRS-R was administered in non-English languages in almost half of the articles. The strength of the cultural adaptations is unknown making it challenging to determine if the results are fit for regulatory decision-making purposes. • Our review suggests a need for further research on the feasibility (including cross-cultural aspects), comparability, and psychometric performance of implementing standardized remote-use ALSFRS-R modalities. [ABSTRACT FROM AUTHOR]

• qEMG showed superior sensitivity to MScanFit MUNE in detecting abnormalities in amyotrophic lateral sclerosis (ALS) at diagnosis. • MScanFit MUNE parameters exhibited good correlations with both muscle strength and qEMG measures in muscles of ALS patients. • MScanFit MUNE and qEMG offered complementary insights for ALS diagnosis. Motor Unit Number Estimation (MUNE) techniques are crucial in assessing lower motor neuron loss. MScanFit MUNE (MScanFit) is a novel tool which estimates MUNE values from compound muscle action potential (CMAP) scans by considering the probabilistic nature of motor unit firing. We conducted a prospective study to evaluate the diagnostic utility of MScanFit compared to quantitative electromyography (qEMG) in ALS patients. We enrolled 35 patients diagnosed with amyotrophic lateral sclerosis (ALS) and 14 healthy controls, assessing qEMG and MScanFit MUNE in abductor pollicis brevis, abductor digiti minimi and tibialis anterior muscles. We found higher sensitivity of qEMG in detecting abnormalities compared to MScanFit, with a high concordance rate between the two techniques. Notably, a few muscles exhibited abnormal MUNE but normal qEMG findings, suggesting a potential complementary role for MScanFit in ALS diagnosis. Neurophysiological parameters from MScanFit showed good correlations with qEMG measures. Subclinical neurophysiological involvement was observed in muscles with normal strength, emphasizing the importance of sensitive diagnostic tools. MScanFit demonstrated validity in distinguishing ALS patients from healthy subjects and correlated well with qEMG parameters. Our study confirmed the diagnostic utility of MScanFit MUNE in ALS, highlighting its role as a supplementary diagnostic tool. [ABSTRACT FROM AUTHOR]

Depression is frequently reported in amyotrophic lateral sclerosis (ALS) due to the disastrous prognosis of progressive motor impairment, but the risk of depression in ALS is still unclear. Therefore, we investigated the risk of depression in ALS and analyzed the effect of ALS-related physical disability on the risk of developing depression using the Korean National Health Insurance Service (KNHIS) database. A total of 2241 ALS patients, as defined by the International Classification Diseases (ICD, G12.21) and Rare Intractable Disease codes (V123), and 1:10 sex- and age-matched controls were selected from the KNHIS. After applying exclusion criteria (non-participation in national health screening, history of depression, or having missing data), 595 ALS patients and 9896 non-ALS individuals were finally selected. Primary outcome is newly diagnosed depression during follow-up duration defined by ICD code (F32 or F33). A Cox regression model was used to examine the hazard ratios (HRs) after adjustment for potential confounders. During the follow-up period, 283 cases of depression in the ALS group and 1547 in the controls were recorded. The adjusted HR for depression in ALS was 9.1 (95% confidence interval [CI] 7.87−10.60). The risk of depression was slightly higher in the disabled ALS group (aHR 10.1, 95% CI 7.98−12.67) than in the non-disabled ALS group (aHR 8.78, 95% CI 7.42−10.39). The relative risk of depression was higher in younger patients than in older patients, and in obese patients than in non-obese patients. Our study showed that ALS patients have an increased risk of depression compared to non-ALS individuals. • Depression is a common psychiatric comorbidity in amyotrophic lateral sclerosis (ALS). • The risk of depression is increased in patients with ALS compared with the non-ALS individuals. • The presence of physical disability is associated with an increased risk of depression in ALS. • The relative risk of depression is higher in younger or obese ALS patients. [ABSTRACT FROM AUTHOR]

RBM45 is an RNA-binding protein with roles in neural development by regulating RNA splicing. Its dysfunction and aggregation are associated with neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar dementia (FTLD). RBM45 harbors three RRM domains that potentially bind RNA. While the recognitions of RNA by its N-terminal tandem RRM domains (RRM1 and RRM2) have been well understood, the RNA-binding property of its C-terminal RRM (RRM3) remains unclear. In this work, we identified that the RRM3 of the RBM45 sequence specifically binds RNA with a GACG sequence, similar but not identical to those recognized by the RRM1 and RRM2. Further, we determined the crystal structure of RBM45RRM3 in complex with a GACG sequence-containing single-stranded DNA. Our structural results, together with the RNA-binding assays of mutants at key amino acid residues, revealed the molecular mechanism by which RBM45RRM3 recognizes an RNA sequence. Our finding on the RNA-binding property of the individual RRM module of RBM45 provides the foundation for unraveling the RNA-binding characteristics of full-length RBM45 and for understanding the biological functions of RBM45. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. Biogen. [ABSTRACT FROM AUTHOR]

• Strength-duration time constant (SDTC) may now be determined for cortical motor neurones. • SDTC is significantly reduced in ALS patients and is correlated with ALS functional rating score, and rate of disease progression. • An increase in transient Na+ conductances may account for the reduction in SDTC. Strength-duration time constant (SDTC) may now be determined for cortical motor neurones, with activity mediated by transient Na+ conductances. The present study determined whether cortical SDTC is abnormal and linked to the pathogenesis of amyotrophic lateral sclerosis. Cortical SDTC and rheobase were estimated from 17 ALS patients using a controllable pulse parameter transcranial magnetic stimulation (cTMS) device. Resting motor thresholds (RMTs) were determined at pulse widths (PW) of 30, 45, 60, 90 and 120 µs and M−ratio of 0.1, using a figure-of-eight coil applied to the primary motor cortex. SDTC was significantly reduced in ALS patients (150.58 ± 9.98 µs; controls 205.94 ± 13.7 µs, P < 0.01). The reduced SDTC correlated with a rate of disease progression (Rho = -0.440, P < 0.05), ALS functional rating score (ALSFRS-R) score (Rho = 0.446, P < 0.05), and disease duration (R = 0.428, P < 0.05). The degree of change in SDTC was greater in patients with cognitive abnormalities as manifested by an abnormal total Edinburgh Cognitive ALS Screen score (140.5 ± 28.7 µs, P < 0.001) and ALS-specific subscore (141.7 ± 33.2 µs, P = 0.003). Cortical SDTC reduction was associated with a more aggressive ALS phenotype, or with more prominent cognitive impairment. An increase in transient Na+ conductances may account for the reduction in SDTC, linked to the pathogenesis of ALS. [ABSTRACT FROM AUTHOR]

• Caregivers of patients with Amyotrophic Lateral Sclerosis (ALS) often experience moderate to severe Caregiver Burden (CB). • The caregiver burden of ALS patients' caregivers tends to increase over time. • The functional decline of ALS patients may negatively affect the quality of life (QoL) of their caregivers and increase their CB. • Mindfulness is a feasible and acceptable intervention that can help reduce CB in caregivers of ALS patients. • Mindfulness can also be an effective intervention to improve the QoL of caregivers. The aim of this study was to evaluate the caregiver burden, mindfulness, and quality of life (QoL) of caregivers of ALS patients and the patient's functional level. This study was conducted with 57 ALS patients and their primary caregivers. The data were collected using the Zarit Burden Interview, Mindful Attention Awareness Scale (MAAS), the Short Form-36 (SF-36), and the ALS Functional Rating Scale (ALS-FRS). The mean age of the caregivers was 49.7 ± 12 years; 66 % were female, and 73.7 % were spouses of the patients. Around 65 % of caregivers experienced a moderate to severe caregiver burden. A low and negative correlation was found between the caregiver burden and mindfulness of caregivers of ALS patients. As the mindfulness levels of the caregivers increased, the caregiver burden decreased, and the physical role difficulty score, one of the sub-dimensions of the QoL, increased. Also, caregivers' QoL decreased as caregiver burden increased (except physical function QoL, p < 0.05). Moreover, there was a positive correlation between the caregiver burden and ALSFRS-R scores (bulbar, motor, respiratory, and total) of the caregivers of ALS patients (p < 0.05). Improved technology for managing ALS disease has increased patient life expectancy. However, caregivers may experience a high burden as the patient's functional level declines. Increasing caregiver mindfulness can help reduce the burden and improve their QoL. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis is a progressive neurodegenerative disorder leading to muscle weakness and respiratory failure. Arimoclomol, a heat-shock protein-70 (HSP70) co-inducer, is neuroprotective in animal models of amyotrophic lateral sclerosis, with multiple mechanisms of action, including clearance of protein aggregates, a pathological hallmark of sporadic and familial amyotrophic lateral sclerosis. We aimed to evaluate the safety and efficacy of arimoclomol in patients with amyotrophic lateral sclerosis. ORARIALS-01 was a multinational, randomised, double-blind, placebo-controlled, parallel-group trial done at 29 centres in 12 countries in Europe and North America. Patients were eligible if they were aged 18 years or older and met El Escorial criteria for clinically possible, probable, probable laboratory-supported, definite, or familial amyotrophic lateral sclerosis; had an ALS Functional Rating Scale-Revised score of 35 or more; and had slow vital capacity at 70% or more of the value predicted on the basis of the participant's age, height, and sex. Patients were randomly assigned (2:1) in blocks of 6, stratified by use of a stable dose of riluzole or no riluzole use, to receive oral arimoclomol citrate 1200 mg/day (400 mg three times per day) or placebo. The Randomisation sequence was computer generated centrally. Investigators, study personnel, and study participants were masked to treatment allocation. The primary outcome was the Combined Assessment of Function and Survival (CAFS) rank score over 76 weeks of treatment. The primary outcome and safety were analysed in the modified intention-to-treat population. This trial is registered with ClinicalTrials.gov , NCT03491462 , and is completed. Between July 31, 2018, and July 17, 2019, 287 patients were screened, 245 of whom were enrolled in the trial and randomly assigned. The modified intention-to-treat population comprised 239 patients (160 in the arimoclomol group and 79 in the placebo group): 151 (63%) were male and 88 (37%) were female; mean age was 57·6 years (SD 10·9). CAFS score over 76 weeks did not differ between groups (mean 0·51 [SD 0·29] in the arimoclomol group vs 0·49 [0·28] in the placebo group; p=0·62). Cliff's delta comparing the two groups was 0·039 (95% CI –0·116 to 0·194). Proportions of participants who died were similar between the treatment groups: 29 (18%) of 160 patients in the arimoclomol group and 18 (23%) of 79 patients in the placebo group. Most deaths were due to disease progression. The most common adverse events were gastrointestinal. Adverse events were more often deemed treatment-related in the arimoclomol group (104 [65%]) than in the placebo group (41 [52%]) and more often led to treatment discontinuation in the arimoclomol group (26 [16%]) than in the placebo group (four [5%]). Arimoclomol did not improve efficacy outcomes compared with placebo. Although available biomarker data are insufficient to preclude future strategies that target the HSP response, safety data suggest that a higher dose of arimoclomol would not have been tolerated. Orphazyme. [ABSTRACT FROM AUTHOR]

• Motor unit number index can provide information on the prognosis of the disease at the first visit in ALS patients. • Motor unit number index score declines faster than the ALS functional rating scale and vital capacity. • A motor unit number index score greater than 378 at the patient's first visit predicts survival beyond one year with a sensitivity of 82% and a specificity of 56%. To evaluate the associations between motor unit number index (MUNIX) and disease progression and prognosis in amyotrophic lateral sclerosis (ALS) in a large-scale longitudinal study. MUNIX was performed at the patient's first visit, at 3, 6, and 12 months in 4 muscles. MUNIX data from the patients were compared with those from 38 age-matched healthy controls. Clinical data included the revised ALS functional rating scale (ALSFRS-R), the forced vital capacity (FVC), and the survival of the patients. Eighty-two patients were included at baseline, 62 were evaluated at three months, 48 at six months, and 33 at twelve months. MUNIX score was lower in ALS patients compared to controls. At baseline, MUNIX was correlated with ALSFRS-R and FVC. Motor unit size index (MUSIX) was correlated with patient survival. Longitudinal analyses showed that MUNIX decline was greater than ALSFRS-R decline at each evaluation. A baseline MUNIX score greater than 378 predicted survival over the 12-month period with a sensitivity of 82% and a specificity of 56%. This longitudinal study suggests that MUNIX could be an early quantitative marker of disease progression and prognosis in ALS. MUNIX might be considered as potential indicator for monitoring disease progression. [ABSTRACT FROM AUTHOR]

• Transcranial magnetic stimulation is an objective biomarker of upper motor neuron dysfunction in motor neuron disease (MND). • Cortical hyperexcitability is mediated by cortical disinhibition and increased facilitation. • Neuroimaging biomarkers of upper motor neuron dysfunction in MND exhibit utility. Identifying upper motor neuron (UMN) dysfunction is fundamental to the diagnosis and understanding of disease pathogenesis in motor neuron disease (MND). The clinical assessment of UMN dysfunction may be difficult, particularly in the setting of severe muscle weakness. From a physiological perspective, transcranial magnetic stimulation (TMS) techniques provide objective biomarkers of UMN dysfunction in MND and may also be useful to interrogate cortical and network function. Single, paired- and triple pulse TMS techniques have yielded novel diagnostic and prognostic biomarkers in MND, and have provided important pathogenic insights, particularly pertaining to site of disease onset. Cortical hyperexcitability, as heralded by reduced short interval intracortical inhibition (SICI) and increased short interval intracortical facilitation, has been associated with the onset of lower motor neuron degeneration, along with patterns of disease spread, development of specific clinical features such as the split hand phenomenon, and may provide an indication about the rate of disease progression. Additionally, reduction of SICI has emerged as a potential diagnostic aid in MND. The triple stimulation technique (TST) was shown to enhance the diagnostic utility of conventional TMS measures in detecting UMN dysfunction in MND. Separately, sophisticated brain imaging techniques have uncovered novel biomarkers of neurodegeneration that have bene associated with progression. The present review will discuss the utility of TMS and brain neuroimaging derived biomarkers of UMN dysfunction in MND, focusing on recently developed TMS techniques and advanced neuroimaging modalities that interrogate structural and functional integrity of the corticomotoneuronal system, with an emphasis on pathogenic, diagnostic, and prognostic utility. [ABSTRACT FROM AUTHOR]

• Avalanche transition matrices are used to investigate the spatio-temporal spreading of neuronal avalanches in ALS; • ALS patients present higher values of the nodal strength in both cortical and sub-cortical brain areas, as compared to controls; • The nodal strength directly correlates with disease duration, corroborating the clinical relevance of brain dynamics. To test the hypothesis that patients affected by Amyotrophic Lateral Sclerosis (ALS) show an altered spatio-temporal spreading of neuronal avalanches in the brain, and that this may related to the clinical picture. We obtained the source-reconstructed magnetoencephalography (MEG) signals from thirty-six ALS patients and forty-two healthy controls. Then, we used the construct of the avalanche transition matrix (ATM) and the corresponding network parameter nodal strength to quantify the changes in each region, since this parameter provides key information about which brain regions are mostly involved in the spreading avalanches. ALS patients presented higher values of the nodal strength in both cortical and sub-cortical brain areas. This parameter correlated directly with disease duration. In this work, we provide a deeper characterization of neuronal avalanches propagation in ALS, describing their spatio-temporal trajectories and identifying the brain regions most likely to be involved in the process. This makes it possible to recognize the brain areas that take part in the pathogenic mechanisms of ALS. Furthermore, the nodal strength of the involved regions correlates directly with disease duration. Our results corroborate the clinical relevance of aperiodic, fast large-scale brain activity as a biomarker of microscopic changes induced by neurophysiological processes. [ABSTRACT FROM AUTHOR]

• Conventional nerve conduction studies, H-reflex studies, and needle electromyography are important tools for the diagnosis of Motor Neuron Disease (MND) • High-density surface EMG, nerve excitability testing, electrical impedance myography, MUNIX, and MScanFit are potential biomarkers for MND. • Neuromuscular ultrasonography can detect changes in nerve and muscle architecture including dynamic changes such as fasciculations. This chapter discusses comprehensive neurophysiological biomarkers utilised in motor neuron disease (MND) and, in particular, its commonest form, amyotrophic lateral sclerosis (ALS). These encompass the conventional techniques including nerve conduction studies (NCS), needle and high-density surface electromyography (EMG) and H-reflex studies as well as novel techniques. In the last two decades, new methods of assessing the loss of motor units in a muscle have been developed, that are more convenient than earlier methods of motor unit number estimation (MUNE), and may use either electrical stimulation (e.g. MScanFit MUNE) or voluntary activation (MUNIX). Electrical impedance myography (EIM) is another novel approach for the evaluation that relies upon the application and measurement of high-frequency, low-intensity electrical current. Nerve excitability techniques (NET) also provide insights into the function of an axon and reflect the changes in resting membrane potential, ion channel dysfunction and the structural integrity of the axon and myelin sheath. Furthermore, imaging ultrasound techniques as well as magnetic resonance imaging are capable of detecting the constituents of morphological changes in the nerve and muscle. The chapter provides a critical description of the ability of each technique to provide neurophysiological insight into the complex pathophysiology of MND/ALS. However, it is important to recognise the strengths and limitations of each approach in order to clarify utility. These neurophysiological biomarkers have demonstrated reliability, specificity and provide additional information to validate and assess lower motor neuron dysfunction. Their use has expanded the knowledge about MND/ALS and enhanced our understanding of the relationship between motor units, axons, reflexes and other neural circuits in relation to clinical features of patients with MND/ALS at different stages of the disease. Taken together, the ultimate goal is to aid early diagnosis, distinguish potential disease mimics, monitor and stage disease progression, quantify response to treatment and develop potential therapeutic interventions. [ABSTRACT FROM AUTHOR]

Terminal Schwann cells (TSCs) are highly specialized, nonmyelinating glia, associated with axon terminals of the somatic peripheral nervous system. TSCs mediate communication between the nervous system and peripheral tissue. They play key roles in the development, stability, and repair of axon terminals and peripheral tissues. Accruing evidence points to maladaptive changes in TSCs contributing to degeneration of peripheral tissues and innervating neurons in diseases and during aging. TSCs contain a unique molecular fingerprint compared to myelinating Schwann cells. The highly specialized nonmyelinating glial cells present at somatic peripheral nerve endings, known collectively as terminal Schwann cells (TSCs), play critical roles in the development, function and repair of their motor and sensory axon terminals and innervating tissue. Over the past decades, research efforts across various vertebrate species have revealed that while TSCs are a diverse group of cells, they share a number of features among them. In this review, we summarize the state-of-knowledge about each TSC type and explore the opportunities that TSCs provide to treat conditions that afflict peripheral axon terminals. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease in which the death of motor neurons leads to loss of muscle function. Additionally, cognitive and circadian disruptions are common in ALS patients, contributing to disease progression and burden. Most ALS cases are sporadic, and environmental exposures contribute to their aetiology. However, animal models of these sporadic ALS cases are scarce. The small vertebrate zebrafish is a leading organism to model neurodegenerative diseases; previous studies have proposed bisphenol A (BPA) or β-methylamino- l -alanine (BMAA) exposure to model sporadic ALS in zebrafish, damaging motor neurons and altering motor responses. Here we characterise the face and predictive validity of sporadic ALS models, showing their potential for the mechanistic study of ALS drugs. We phenotypically characterise the BPA and BMAA-induced models, going beyond motor activity and motor axon morphology, to include circadian, redox, proteostasis, and metabolomic phenotypes, and assessing their predictive validity for ALS modelling. BPA or BMAA exposure induced concentration-dependent activity impairments. Also, exposure to BPA but not BMAA induced motor axonopathy and circadian alterations in zebrafish larvae. Our further study of the BPA model revealed loss of habituation to repetitive startles, increased oxidative damage, endoplasmic reticulum (ER) stress, and metabolome abnormalities. The BPA-induced model shows predictive validity, since the approved ALS drug edaravone counteracted BPA-induced motor phenotypes, ER stress, and metabolic disruptions. Overall, BPA exposure is a promising model of ALS-related redox and ER imbalances, contributing to fulfil an unmet need for validated sporadic ALS models. [Display omitted] • We characterise face and predictive validity of zebrafish models of sporadic ALS (sALS). • Phenotypes of sALS models include behavioural impairments and axonopathy. • BPA-induced sALS model shows altered metabolism and increased ER/redox stress. • ALS drug edaravone counteracts sALS phenotypes, modulating ER stress and metabolism. [ABSTRACT FROM AUTHOR]

Ectodysplasin A2 receptor (EDA2R) upregulation in skeletal muscle is associated with aging, denervation, and disease states causing muscle wasting, such as cancer cachexia, muscular dystrophies, critical illness myopathy, and amyotrophic lateral sclerosis. EDA2R signaling, which involves the noncanonical NFκB pathway and NFκB-inducing kinase (NIK), promotes atrophy and insulin resistance in skeletal muscle. Depletion of EDA2R and NIK in mice ameliorates muscle loss linked to cancer cachexia, indicating that therapeutic targeting of this pathway can be beneficial in muscle wasting diseases. Inhibition of the EDA2R–NIK axis improves insulin sensitivity in muscle. Skeletal muscle is essential in generating mechanical force and regulating energy metabolism and body temperature. Pathologies associated with muscle tissue often lead to impaired physical activity and imbalanced metabolism. Recently, ectodysplasin A2 receptor (EDA2R) signaling has been shown to promote muscle loss and glucose intolerance. Upregulated EDA2R expression in muscle tissue was associated with aging, denervation, cancer cachexia, and muscular dystrophies. Here, we describe the roles of EDA2R signaling in muscle pathophysiology, including muscle atrophy, insulin resistance, and aging-related sarcopenia. We also discuss the EDA2R pathway, which involves EDA-A2 as the ligand and nuclear factor (NF)κB-inducing kinase (NIK) as a downstream mediator, and the therapeutic potential of targeting these proteins in the treatment of muscle wasting and metabolic dysfunction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Whole body motor unit MRI (MUMRI) offers a sensitive and non-invasive method to image fasciculation in multiple body regions. • Whole body MUMRI fasciculation rates correlated with single channel surface EMG fasciculation rates. • MUMRI discriminated well between ALS patients and healthy people for proximal limb and paraspinal muscles, but not the tongue. Compare fasciculation rates between amyotrophic lateral sclerosis (ALS) patients and healthy controls in body regions relevant for diagnosing ALS using motor unit MRI (MUMRI) at baseline and 6 months follow-up, and relate this to single-channel surface EMG (SEMG). Tongue, biceps brachii, paraspinals and lower legs were assessed with MUMRI and biceps brachii and soleus with SEMG in 10 healthy controls and 10 patients (9 typical ALS, 1 primary lateral sclerosis [PLS]). MUMRI-detected fasciculation rates in typical ALS patients were higher compared to healthy controls for biceps brachii (2.40 ± 1.90 cm-3min−1 vs. 0.04 ± 0.10 cm-3min−1, p = 0.004), paraspinals (1.14 ± 1.61 cm-3min−1 vs. 0.02 ± 0.02 cm-3min−1, p = 0.016) and lower legs (1.42 ± 1.27 cm-3min−1 vs. 0.13 ± 0.10 cm-3min−1, p = 0.004), but not tongue (1.41 ± 1.94 cm-3min−1 vs. 0.18 ± 0.18 cm-3min−1, p = 0.556). The PLS patient showed no fasciculation. At baseline, 6/9 ALS patients had increased fasciculation rates compared to healthy controls in at least 2 body regions. At follow-up every patient had increased fasciculation rates in at least 2 body regions. The MUMRI-detected fasciculation rate correlated with SEMG-detected fasciculation rates (τ = 0.475, p = 0.006). MUMRI can non-invasively image fasciculation in multiple body regions and appears sensitive to disease progression in individual patients. MUMRI has potential as diagnostic tool for ALS. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease of motor neurons. Neuronal superoxide dismutase-1 (SOD1) inclusion bodies are characteristic of familial ALS with SOD1 mutations, while a hallmark of sporadic ALS is inclusions containing aggregated WT TAR DNAbinding protein 43 (TDP-43). We show here that coexpression of mutant or WT TDP-43 with SOD1 leads to misfolding of endogenous SOD1 and aggregation of SOD1 reporter protein SOD1G85R-GFP in human cell cultures and promotes synergistic axonopathy in zebrafish. Intriguingly, this pathological interaction is modulated by natively solventexposed tryptophans in SOD1 (tryptophan-32) and TDP-43 RNA-recognition motif RRM1 (tryptophan-172), in concert with natively sequestered TDP-43 N-terminal domain tryptophan-68. TDP-43 RRM1 intrabodies reduce WT SOD1 misfolding in human cell cultures, via blocking tryptophan172. Tryptophan-68 becomes antibody-accessible in aggregated TDP-43 in sporadic ALS motor neurons and cell culture. 5-fluorouridine inhibits TDP-43–induced G85R-GFP SOD1 aggregation in human cell cultures and ameliorates axonopathy in zebrafish, via its interaction with SOD1 tryptophan-32. Collectively, our results establish a novel and potentially druggable tryptophan-mediated mechanism whereby two principal ALS disease effector proteins might directly interact in disease. [ABSTRACT FROM AUTHOR]

Growing evidences indicate that dysfunction of autophagy contributes to the disease pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two neurodegenerative disorders. The GGGGCC·GGCCCC repeat RNA expansion in chromosome 9 open reading frame 72 (C9orf72) is the most genetic cause of both ALS and FTD. According to the previous studies, GGGGCC·GGCCCC repeat undergoes the unconventional repeat-associated non-ATG translation, which produces dipeptide repeat (DPR) proteins. Although there is a growing understanding that C9orf72 DPRs have a strong ability to harm neurons and induce C9orf72 -linked ALS/FTD, whether these DPRs can affect autophagy remains unclear. In the present study, we find that poly-GR and poly-PR, two arginine-containing DPRs which display the most cytotoxic properties according to the previous studies, strongly inhibit starvation-induced autophagy. Moreover, our data indicate that arginine-rich DPRs enhance the interaction between BCL2 and BECN1/Beclin 1 by inhibiting BCL2 phosphorylation, therefore they can impair autophagic clearance of neurodegenerative disease-associated protein aggregates under starvation condition in cells. Importantly, our study not only highlights the role of C9orf72 DPR in autophagy dysfunction, but also provides novel insight that pharmacological intervention of autophagy using SW063058, a small molecule compound that can disrupt the interaction between BECN1 and BCL2, may reduce C9orf72 DPR-induced neurotoxicity. ALS/FTD-linked C9orf72 DPRs inhibit starvation-induced autophagy by enhancing BCL2–BECN1/Beclin 1 interaction. Under this condition, pharmacological disruption of the interaction between BECN1 and BCL2 can restore autophagy and may therefore reduce C9orf72 DPR-induced neurotoxicity. [Display omitted] [ABSTRACT FROM AUTHOR]

• This article reviews the organization and function of the human corticospinal tract and its cortico-motoneuronal connections. • Accumulating evidence suggests the motor symptoms of ALS reflect pathology selectively targeting cortico-motoneuronal connections. • Dysfunction and degeneration of cortico-motoneuronal connections impacts not only muscle strength but also motor skill; effects on the latter may be the distinctive feature of ALS. Corticospinal neurons located in motor areas of the cerebral neocortex project corticospinal axons which synapse with the spinal network; a parallel corticobulbar system projects to the cranial motor network and to brainstem motor pathways. The primate corticospinal system has a widespread cortical origin and an extensive range of different fibre diameters, including thick, fast-conducting axons. Direct cortico-motoneuronal (CM) projections from the motor cortex to arm and hand alpha motoneurons are a recent evolutionary feature, that is well developed in dexterous primates and particularly in humans. Many of these projections originate from the caudal subdivision of area 4 ('new' M1: primary motor cortex). They arise from corticospinal neurons of varied soma size, including those with fast- and relatively slow-conducting axons. This CM system has been shown to be involved in the control of skilled movements, carried out with fractionation of the distal extremities and at low force levels. During movement, corticospinal neurons are activated quite differently from 'lower' motoneurons, and there is no simple or fixed functional relationship between a so-called 'upper' motoneuron and its target lower motoneuron. There are key differences in the organisation and function of the corticospinal and CM system in primates versus non-primates, such as rodents. These differences need to be recognized when making the choice of animal model for understanding disorders such as amyotrophic lateral sclerosis (ALS). In this neurodegenerative brain disease there is a selective loss of fast-conducting corticospinal axons, and their synaptic connections, and this is reflected in responses to non-invasive cortical stimuli and measures of cortico-muscular coherence. The loss of CM connections influencing distal limb muscles results in a differential loss of muscle strength or 'split-hand' phenotype. Importantly, there is also a unique impairment in the coordination of skilled hand tasks that require fractionation of digit movement. Scores on validated tests of skilled hand function could be used to assess disease progression. [ABSTRACT FROM AUTHOR]

• The GNRI has the potential prognostic value for patients with ALS. • Lower GNRI were linked with a shorter survival time in patients with ALS. • GNRI was an independent predictor of survival time in patients with ALS. • A lower GNRI was found in bulbar onset patients than in limb onset patients. • The GNRI level was correlated with ALSFRS-R score, onset age, onset site, and FVC%. The geriatric nutritional risk index (GNRI) is a prognostic indicator for several diseases, meanwhile, nutrition and inflammation play important roles in the disease progression of amyotrophic lateral sclerosis (ALS). However, the association between the GNRI and ALS remains unknown. 443 patients diagnosed with ALS were divided into two groups based on the GNRI levels. Associations between GNRI and survival time were analyzed using Kaplan-Meier curves and compared by the log-rank test. Univariate and multivariate analyses were used to assess their prognostic values for survival time. Spearman correlation analysis was used to evaluate the correlation coefficients between GNRI and other clinical variables. No significant differences were found in diagnostic delay between the two groups. The onset age and disease progression rate (DPR) were significantly lower in high GNRI group while forced vital capacity (FVC), revised version of the ALS functional rating scale (ALSFRS-R), serum albumin and body mass index (BMI) were significantly lower in low GNRI group. Lower GNRI levels were linked with shorter ALS patients' survival time by Kaplan-Meier curves. The univariate and multivariate analysis identified the onset age, gender, onset site, diagnostic delay, DRP and GNRI as predictors of survival time in patients with ALS. Nutritional status was closely corelated with ALS progression. The GNRI may be used as a potential prognostic indictor for ALS patients. [ABSTRACT FROM AUTHOR]

Downregulating superoxide dismutase 1 (SOD1) by regular injections of antisense oligos (ASOs) interacting with SOD1 mRNA is a new FDA-approved therapy for patients with amyotrophic lateral sclerosis (ALS) with mutations in SOD1. Understanding the exact molecular mechanism of a disease is crucial in order to develop the correct ASO strategy as is convincingly shown by the failure of the C9orf72 ASO trials. Rare forms of genetic ALS benefit from individual treatment programs using specific ASOs directed against the disease-causing gene. Restoring splice defects in different mRNAs using ASOs counteracts the negative effects of nuclear depletion of TDP-43, which is observed in the majority of patients with ALS. ASOs influencing risk factors for ALS or proteins involved in general disease mechanisms underlying ALS could also open new therapeutic perspectives for patients with sporadic ALS. Treatment of patients with amyotrophic lateral sclerosis (ALS) has entered a new era now that encouraging results about antisense oligonucleotides (ASOs) are becoming available and a first ASO therapy for ALS has been approved by the FDA. Moreover, there is hope not only that ALS can be stopped but also that symptoms can be reversed. Until now, degrading ASOs seemed to be successful mostly for rarer forms of familial ALS. However, the first attempts to correct mis-splicing events in sporadic ALS are underway, as well as a clinical trial examining interference with a genetic modifier. In this review, we discuss the current status of using ASOs in ALS and the possibilities and pitfalls of this therapeutic strategy. [ABSTRACT FROM AUTHOR]

• In clinical needle EMG interpretation, conventional machine learning methods were more often studied than deep learning methods. • Most studies developed models for classification of contraction signals and a few addressed the classification of rest signals. • Current research has methodological shortcomings, which prevent clinical implementation, but are surmountable. This scoping review provides an overview of artificial intelligence (AI), including machine and deep learning techniques, in the interpretation of clinical needle electromyography (nEMG) signals. A comprehensive search of Medline, Embase and Web of Science was conducted to find peer-reviewed journal articles. All papers published after 2010 were included. The methodological quality of the included studies was assessed with CLAIM (checklist for artificial intelligence in medical imaging). 51 studies were identified that fulfilled the inclusion criteria. 61% used open-source EMGlab data set to develop models to classify nEMG signal in healthy, amyotrophic lateral sclerosis (ALS) and myopathy (25 subjects). Only two articles developed models to classify signals recorded at rest. Most articles reported high performance accuracies, but many were subject to bias and overtraining. Current AI-models of nEMG signals are not sufficient for clinical implementation. Suggestions for future research include emphasizing the need for an optimal training and validation approach using large datasets of clinical nEMG data from a diverse patient population. The outcomes of this study and the suggestions made aim to contribute to developing AI-models that can effectively handle signal quality variability and are suitable for daily clinical practice in interpreting nEMG signals. [ABSTRACT FROM AUTHOR]

FUS and TDP-43 are two self-adhesive aggregation-prone mRNA-binding proteins whose pathological mutations have been linked to neurodegeneration. While TDP-43 and FUS form reversible mRNA-rich compartments in the nucleus, pathological mutations promote their respective cytoplasmic aggregation in neurons with no apparent link between the two proteins except their intertwined function in mRNA processing. By combining analyses in cellular context and at high resolution in vitro, we unraveled that TDP-43 is specifically recruited in FUS assemblies to form TDP-43-rich subcompartments but without reciprocity. The presence of mRNA provides an additional scaffold to promote the mixing between TDP-43 and FUS. Accordingly, we also found that the pathological truncated form of TDP-43, TDP-25, which has an impaired RNA-binding ability, no longer mixes with FUS. Together, these results suggest that the binding of FUS along nascent mRNAs enables TDP-43, which is highly aggregationprone, to mix with FUS phase to form mRNA-rich subcompartments. A functional link between FUS and TDP-43 may explain their common implication in amyotrophic lateral sclerosis. [ABSTRACT FROM AUTHOR]

Tandem GGGGCC repeat expansion in C9orf72 is a genetic cause of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Transcribed repeats are translated into dipeptide repeat proteins via repeat-associated non-AUG (RAN) translation. However, the regulatory mechanism of RAN translation remains unclear. Here, we reveal a GTPase-activating protein, eukaryotic initiation factor 5 (eIF5), which allosterically facilitates the conversion of eIF2-bound GTP into GDP upon start codon recognition, as a novel modifier of C9orf72 RAN translation. Compared to global translation, eIF5, but not its inactive mutants, preferentially stimulates poly-GA RAN translation. RAN translation is increased during integrated stress response, but the stimulatory effect of eIF5 on poly-GA RAN translation was additive to the increase of RAN translation during integrated stress response, with no further increase in phosphorylated eIF2a. Moreover, an alteration of the CUG near cognate codon to CCG or AUG in the poly-GA reading frame abolished the stimulatory effects, indicating that eIF5 primarily acts through the CUGdependent initiation. Lastly, in a Drosophila model of C9orf72 FTLD/ALS that expresses GGGGCC repeats in the eye, knockdown of endogenous eIF5 by two independent RNAi strains significantly reduced poly-GA expressions, confirming in vivo effect of eIF5 on poly-GA RAN translation. Together, eIF5 stimulates the CUG initiation of poly-GA RAN translation in cellular and Drosophila disease models of C9orf72 FTLD/ALS. [ABSTRACT FROM AUTHOR]

The RNA/DNA helicase senataxin (SETX) has been involved in multiple crucial processes related to genome expression and integrity such us transcription termination, the regulation of transcription-replication conflicts and the resolution of R-loops. SETX has been the focus of numerous studies since the discovery that mutations in its coding gene are the root cause of two different neurodegenerative diseases: Ataxia with Oculomotor Apraxia type 2 (AOA2) and a juvenile form of Amyotrophic Lateral Sclerosis (ALS4). A plethora of cellular phenotypes have been described as the result of SETX deficiency, yet the precise molecular function of SETX as well as the molecular pathways leading from SETX mutations to AOA2 and ALS4 pathologies have remained unclear. However, recent data have shed light onto the biochemical activities and biological roles of SETX, thus providing new clues to understand the molecular consequences of SETX mutation. In this review we summarize near two decades of scientific effort to elucidate SETX function, we discuss strengths and limitations of the approaches and models used thus far to investigate SETX-associated diseases and suggest new possible research avenues for the study of AOA2 and ALS4 pathogenesis. • SETX play roles in transcription termination and the regulation of gene expression. • SETX is crucial for R-loops control and the maintenance of genome stability. • SETX is an RNA/DNA helicase with evolutionary conserved biochemical activities. • Mutations in the SETX gene are linked to two distinct neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

• Non-invasive brain and spinal stimulation techniques have been investigated as a potential treatment in motoneuron disease. • Stimulation methods aim at counteracting glutamate-mediated excitotoxicity leading to motoneuron degeneration. • Targeted, individualized and home-deliverable treatments are critical challenges for future advancements. Non-invasive brain stimulation techniques have been exploited in motor neuron disease (MND) with multifold objectives: to support the diagnosis, to get insights in the pathophysiology of these disorders and, more recently, to slow down disease progression. In this review, we consider how neuromodulation can now be employed to treat MND, with specific attention to amyotrophic lateral sclerosis (ALS), the most common form with upper motoneuron (UMN) involvement, taking into account electrophysiological abnormalities revealed by human and animal studies that can be targeted by neuromodulation techniques. This review article encompasses repetitive transcranial magnetic stimulation methods (including low-frequency, high-frequency, and pattern stimulation paradigms), transcranial direct current stimulation as well as experimental findings with the newer approach of trans-spinal direct current stimulation. We also survey and discuss the trials that have been performed, and future perspectives. [ABSTRACT FROM AUTHOR]

• Quantifying mirror activity in ALS patients can be readily achieved using a novel algorithm. • Increase of mirror activity seems to precede changes in other measures of motor function and transcallosal inhibition. • Further studies are warranted to evaluate the potential utility of this approach as a biomarker for ALS. To investigate mirror activity in amyotrophic lateral sclerosis (ALS) patients, using a simple paradigm of signal quantification. Patients were asked to perform a brief isometric maximum contraction of the abductor digiti minimi (ADM) or tibialis anterior (TA) on one side, while relaxing the contralateral side of the body. Both sides were investigated. Signals were stored and analyzed offline, for quantification of electromyographic signal. Clinical signs of upper motor neuron (UMN) dysfunction, transcranial magnetic stimulation (TMS) for the upper (UL) and lower limbs (LL), the ADM ipsilateral cortical silent period (iSP) and the Edinburgh Cognitive and Behavioral ALS Screen (ECAS) cognitive scale were also investigated. 42 ALS patients were included. In the 4 investigated muscles the amount of mirror activity was significantly higher than in the matched healthy group. The amount of mirror activity was similar between sides, but significantly higher in UL and LL with abnormal TMS results for ADM (p = 0.005) and TA (p = 0.002), as well as in UL with abnormal iSP values (p = 0.009). No association was found between mirror activity and clinical signs of UMN involvement. Mirror activity is a common phenomenon in ALS. Mirror activity intensity corresponds to the severity of UMN dysfunction, as measured by TMS, and probably derives from the abnormal transcallosal inhibition as mirrored by iSP abnormality. Mirror activity is increased in ALS and is associated with abnormal transcallosal inhibition and UMN dysfunction. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a fatal disease associated with motor neuron degeneration, accumulation of aggregated misfolded proteins and neuroinflammation in motor regions of the central nervous system (CNS). Clinical trials using regulatory T cells (Tregs) are ongoing because of Tregs' immunomodulatory function, ability to traffic to the CNS, high numbers correlating with slower disease in ALS and disease-modifying activity in ALS mouse models. In the current study, a chimeric antigen receptor (CAR) was developed and characterized in human Tregs to enhance their immunomodulatory activity when in contact with an ALS protein aggregate. A CAR (DG05-28-3z) consisting of a human superoxide dismutase 1 (hSOD1)-binding single-chain variable fragment, CD28 hinge, transmembrane and co-stimulatory domain and CD3ζ signaling domain was created and expressed in human Tregs. Human Tregs were isolated by either magnetic enrichment for CD4+CD25hi cells (Enr-Tregs) or cell sorting for CD4+CD25hiCD127lo cells (FP-Tregs), transduced and expanded for 17 days. The CAR bound preferentially to the ALS mutant G93A-hSOD1 protein relative to the wild-type hSOD1 protein. The CAR Tregs produced IL-10 when cultured with aggregated G93A-hSOD1 proteins or spinal cord explants from G93A-hSOD1 transgenic mice. Co-culturing DG05-28-3z CAR Tregs with human monocytes/macrophages inhibited production of tumor necrosis factor alpha and reactive oxygen species. Expanded FP-Tregs resulted in more robust Tregs compared with Enr-Tregs. FP-Tregs produced similar IL-10 and less interferon gamma, had lower Treg-specific demethylated region methylation and expressed higher FoxP3 and CD39. Taken together, this study demonstrates that gene-modified Tregs can be developed to target an aggregated ALS-relevant protein to elicit CAR-mediated Treg effector functions and provides an approach for generating Treg therapies for ALS with the goal of enhanced disease site-specific immunomodulation. [ABSTRACT FROM AUTHOR]

Heterogeneous nuclear ribonucleoproteins (hnRNPs) possess a modular architecture, featuring long disordered low-complexity domains (LCDs) that drive their assembly into either functional or pathological amyloid structures. Hereditary mutations in hnRNP LCDs have been associated with multiple human neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia, Alzheimer's disease, and Parkinson's disease. Functional amyloid assemblies formed by hnRNPs tend to display limited polymorphism, while pathological aggregates often exhibit structural diversity. Unlike pathological amyloids, most amyloid assemblies formed by hnRNPs rely on polar residues and hydrogen bonding for stabilizing their structure. Full-length hnRNPDL-2 assembles into active amyloids, displaying a functional solenoidal coat of RNA recognition motifs (RRMs) that enables to bind DNA and RNA. Amyloids are implicated in neurodegenerative and systemic diseases, yet they serve important functional roles in numerous organisms. Heterogeneous nuclear ribonucleoproteins (hnRNPs) represent a large family of RNA-binding proteins (RBPs) that control central events of RNA biogenesis in normal and diseased cellular conditions. Many of these proteins contain prion-like sequences of low complexity, which not only assemble into functional fibrils in response to cellular cues but can also lead to disease when missense mutations arise in their sequences. Recent advances in cryo-electron microscopy (cryo-EM) have provided unprecedented high-resolution structural insights into diverse amyloid assemblies formed by hnRNPs and structurally related RBPs, including TAR DNA-binding protein 43 (TDP-43), Fused in Sarcoma (FUS), Orb2, hnRNPA1, hnRNPA2, and hnRNPDL-2. This review provides a comprehensive overview of these structures and explores their functional and pathological implications. [ABSTRACT FROM AUTHOR]

Heterogeneous nuclear ribonucleoprotein A2 (hnRNPA2) is a human ribonucleoprotein that transports RNA to designated locations for translation via its ability to phase separate. Its mutated form, D290V, is implicated in multisystem proteinopathy known to afflict two families, mainly with myopathy and Paget's disease of bone. Here, we investigate this mutant form of hnRNPA2 by determining cryo-EM structures of the recombinant D290V low complexity domain. We find that the mutant form of hnRNPA2 differs from the WT fibrils in four ways. In contrast to the WT fibrils, the PY-nuclear localization signals in the fibril cores of all three mutant polymorphs are less accessible to chaperones. Also, the mutant fibrils are more stable than WT fibrils as judged by phase separation, thermal stability, and energetic calculations. Similar to other pathogenic amyloids, the mutant fibrils are polymorphic. Thus, these structures offer evidence to explain how a D-to-V missense mutation diverts the assembly of reversible, functional amyloid-like fibrils into the assembly of pathogenic amyloid, and may shed light on analogous conversions occurring in other ribonucleoproteins that lead to neurological diseases such as amyotrophic lateral sclerosis and frontotemporal dementia. [ABSTRACT FROM AUTHOR]

Hexanucleotide repeat expansion in C9orf72 is one of the most common causes of amyotrophic lateral sclerosis and frontotemporal dementia. The hexanucleotide expansion, formed by GGGGCC (G4C2) repeats, leads to the production of five dipeptide protein repeats (DPRs) via repeat-associated non-AUG translation. Among the five dipeptide repeats, Gly-Arg, Pro-Arg, and Gly-Ala form neuronal inclusions that contain aggregates of the peptides. Several studies have attempted to model DPR-associated toxicity using various repeat lengths, which suggests a unique conformation that is cytotoxic and is independent of the repeat length. However, the structural characteristics of DPR aggregates have yet to be determined. Increasing evidence suggests that soluble species, such as oligomers, are the main cause of toxicity in proteinopathies, such as Alzheimer's and Parkinson's disease. To investigate the ability of DPRs to aggregate and form toxic oligomers, we adopted a reductionist approach using small dipeptide repeats of 3, 6, and 12. This study shows that DPRs, particularly glycine-arginine and proline-arginine, form oligomers that exhibit distinct dye-binding properties and morphologies. Importantly, we also identified toxic DPR oligomers in amyotrophic lateral sclerosis and frontotemporal dementia postmortem brains that are morphologically similar to those generated recombinantly. This study demonstrates that, similar to soluble oligomers formed by various amyloid proteins, DPR oligomers are toxic, independent of their repeat length. [ABSTRACT FROM AUTHOR]

Current genome-wide association studies of frontotemporal dementia (FTD) are underpowered due to limited samples. Further, common genetic etiologies between FTD and amyotrophic lateral sclerosis (ALS) remain unknown. Using the largest summary statistics of FTD (3526 cases and 9402 controls) and ALS (27,205 cases and 110,881 controls), we found a significant genetic correlation between them ( r ˆ g = 0.637, P = 0.032) and identified 190 FTD-related variants within 5 loci (3p22.1, 5q35.1, 9p21.2, 19p13.11, and 20q13.13). Among these, ALS and FTD had causal variants in 9p21.2 and 19p13.11. Moreover, MOBP (3p22.1), C9orf72 (9p21.2), MOB3B (9p21.2), UNC13A (19p13.11), SLC9A8 (20q13.13), SNAI1 (20q13.13), and SPATA2 (20q13.13) were discovered by both SNP- and gene-level analyses, which together discovered 15 FTD-associated genes, with 10 not detected before (IFNK , RNF114 , SLC9A8 , SPATA2 , SNAI1 , SCFD1 , POLDIP2 , TMEM97, G2E3 , and PIGW). Functional analyses showed these genes were enriched in heart left ventricle, kidney cortex, and some brain regions. Overall, this study provides insights into genetic determinants of FTD and shared genetic etiology underlying FTD and ALS. [ABSTRACT FROM AUTHOR]

• Respiratory failure is a primary cause of mortality in individuals with VCP multisystem. • Respiratory resistance training strengthens inspiratory muscles. • Maximum inspiratory pressure increased significantly by a mean of 0.392cm. H 2 O/week. • Remote respiratory resistance treatments are feasible and successful. Valosin-containing protein (VCP) disease is an autosomal dominant multisystem proteinopathy associated with hereditary inclusion body myopathy, Paget disease of bone, and frontotemporal dementia. Myopathy frequently results in respiratory muscle weakness, leading to early mortality due to respiratory failure. We investigated the effects of a remotely administered inspiratory muscle training program in individuals with VCP disease. Nine adults with VCP mutation-positive familial myopathy without evidence of dementia were recruited for a 40-week remotely administered study. Baseline performance was established during the first 8 weeks, followed by 32 weeks of inspiratory muscle training. The primary outcome was maximum inspiratory pressure (MIP). The secondary and exploratory endpoints included spirometry, grip strength, Inclusion Body Myopathy Functional Rating Scale (IBMFRS), Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS), timed up and go, and six-minute walk test (6MWT). During the treatment phase, MIP increased significantly by a weekly mean of 0.392cm. H 2 O (p =0.023). In contrast, grip strength and ALSFRS significantly decreased by 0.088 lbs. (p =0.031) and 0.043 points (p =0.004) per week, respectively, as expected from the natural progression of this disease. A remotely administered inspiratory muscle training program is therefore feasible, safe, and well-tolerated in individuals with VCP disease and results in improved inspiratory muscle strength. [ABSTRACT FROM AUTHOR]

• VCP-Multisystem proteinopathy (MSP) can manifest in the pediatric population. • We report a novel VCP pathogenic variant c.467G > T , p.Gly156Val. • The novel VCP variant leads to adolescent-onset inclusion body myopathy. Valosin-containing protein (VCP) pathogenic variants are the most common cause of multisystem proteinopathy presenting with inclusion body myopathy, amyotrophic lateral sclerosis/frontotemporal dementia, and Paget disease of bone in isolation or in combination. We report a patient manifesting with adolescent-onset myopathy caused by a novel heterozygous VCP variant (c.467G > T , p.Gly156Val). The myopathy manifested asymmetrically in lower limbs and extended to proximal, axial, and upper limb muscles, with loss of ambulation at age 35. Creatine kinase value was normal. Alkaline phosphatase was elevated. Electromyography detected mixed low amplitude, short duration and high amplitude, long duration motor unit potentials. Muscle biopsy showed features of inclusion body myopathy, which in combination with newly diagnosed Paget disease of bone, supported the VCP variant pathogenicity. In conclusion, VCP -multisystem proteinopathy is not only a disease of adulthood but can have a pediatric onset and should be considered in differential diagnosis of neuromuscular weakness in the pediatric population. [ABSTRACT FROM AUTHOR]

• Cutaneous silent period (CSP) latency of single motor units is prolonged in severely affected ALS patients, whereas the duration of CSP remained similar to healthy controls. • Discharge rate estimation revealed longer CSP duration compared to probabilistic methods. • Severely and mildly affected ALS patients lose motor unit discharge rate vs. CSP duration inverse correlation. Recent evidence indicated that amyotrophic lateral sclerosis (ALS) also impairs spinal circuits, including those mediating cutaneous silent period (CSP). However, most studies utilised surface electromyography (sEMG), which needs more resolution to pinpoint changes at the single motoneuron level. We aimed to investigate CSP properties using single motor unit discharges in ALS. In mild and severe ALS patients and controls, CSP was recorded in the first dorsal interosseus and analysed using the discharge rate method, which accurately shows the inhibitory postsynaptic potentials (IPSPs) profile. Our findings confirmed that the CSP latency was prolonged only in severe ALS patients. Moreover, the CSP duration was similar in each group, but late-stage ALS patients tend to have a longer CSP duration. The discharge rate method revealed a significantly longer duration (up to 150 ms) than the duration detected using sEMG. Strikingly, the motoneuron discharge rate – IPSP duration inverse relationship is lost in ALS patients, indicating a possible impairment in the motoneuron integrative properties. Our data support previous findings of prolonged latency, presented input–output modifications of motoneurons, and revealed the entire course of the CSP, representing a much stronger inhibitory event than previously thought. Motoneuron integrative property modification assessed by CSP could be a new biomarker for ALS. [ABSTRACT FROM AUTHOR]

Autophagy is a degradative pathway that plays an important role in maintaining cellular homeostasis. Dysfunction of autophagy is associated with the progression of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Although one of the typical features of brain aging is an accumulation of redox-active metals that eventually lead to neurodegeneration, a plausible link between trace metal-induced neurodegeneration and dysregulated autophagy has not been clearly determined. Here, we used a cupric chloride-induced neurodegeneration model in MN9D dopaminergic neuronal cells along with ultrastructural and biochemical analyses to demonstrate impaired autophagic flux with accompanying lysosomal dysfunction. We found that a surge of cytosolic calcium was involved in cupric chlorideinduced dysregulated autophagy. Consequently, buffering of cytosolic calcium by calbindin-D28K overexpression or cotreatment with the calcium chelator BAPTA attenuated the cupric chloride-induced impairment in autophagic flux by ameliorating dysregulation of lysosomal function. Thus, these events allowed the rescue of cells from cupric chloride-induced neuronal death. These phenomena were largely confirmed in cupric chloride-treated primary cultures of cortical neurons. Taken together, these results suggest that abnormal accumulation of trace metal elements and a resultant surge of cytosolic calcium leads to neuronal death by impairing autophagic flux at the lysosomal level. [ABSTRACT FROM AUTHOR]

White matter injury is a generalizable phenomenon across a spectrum of chronic, neurodegenerative conditions, including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). The oligodendrocyte (OL) lineage is disrupted early during neurodegeneration with dysfunction appearing before the onset of clinical symptoms. Despite different etiologies in AD, PD, and ALS, there are common pathological cellular and molecular pathways that converge on the OL lineage including neuroinflammation, protein aggregation, lipid dysregulation, and organellar stress. Future work is needed to explore whether therapeutically restoring OL function can ameliorate clinical signs in patients with chronic neurodegenerative conditions. Oligodendrocytes (OLs), the myelin-generating cells of the central nervous system (CNS), are active players in shaping neuronal circuitry and function. It has become increasingly apparent that injury to cells within the OL lineage plays a central role in neurodegeneration. In this review, we focus primarily on three degenerative disorders in which white matter loss is well documented: Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). We discuss clinical data implicating white matter injury as a key feature of these disorders, as well as shared and divergent phenotypes between them. We examine the cellular and molecular mechanisms underlying the alterations to OLs, including chronic neuroinflammation, aggregation of proteins, lipid dysregulation, and organellar stress. Last, we highlight prospects for therapeutic intervention targeting the OL lineage to restore function. [ABSTRACT FROM AUTHOR]

• What is the primary question addressed by this study? Neuropsychiatric symptoms are often early signs of neurodegenerative diseases, contributing to misdiagnosis of these conditions. Among neurodegenerative diseases, TDP-43 proteinopathies are a common cause of neuropsychiatric symptoms and are under-recognized by clinicians, including geriatric psychiatrists. A better understanding of the relationship between neuropsychiatric symptoms and underlying TDP-43 neuropathology may improve recognition, diagnosis, and disease management. • What is the main finding of this study? Psychiatric symptoms are prevalent in frontotemporal dementia (FTD) and related disorders and can vary based on TDP-43 neuropathology subtype. Depression and anxiety are often early presentations in FTD caused by GRN gene mutations, while FTD cases caused by repeat expansions in the C9orf72 gene demonstrate a higher rate of psychosis and somatic delusions. • What is the meaning of the finding? Late-onset neuropsychiatric symptoms can be the initial manifestation of sporadic and genetic TDP-43–related diseases, including FTD and amyotrophic lateral sclerosis (ALS), and TDP-43 pathology is often comorbid in Alzheimer's disease. Psychiatrists must play a key role in the differential diagnosis of these patients, who require complex biopsychosocial interventions and may be eligible for emerging clinical trial opportunities for potentially disease-modifying therapies. Neuropsychiatric symptoms (NPS) are common manifestations of neurodegenerative disorders and are often early signs of those diseases. Among those neurodegenerative diseases, TDP-43 proteinopathies are an increasingly recognized cause of early neuropsychiatric manifestations. TDP-43–related diseases include frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), and Limbic-Predominant Age-Related TDP-43 Encephalopathy (LATE). The majority of TDP-43–related diseases are sporadic, but a significant proportion is hereditary, with progranulin (GRN) mutations and C9orf72 repeat expansions as the most common genetic etiologies. Studies reveal that NPS can be the initial manifestation of those diseases or can complicate disease course, but there is a lack of awareness among clinicians about TDP-43–related diseases, which leads to common diagnostic mistakes or delays. There is also emerging evidence that TDP-43 accumulations could play a role in late-onset primary psychiatric disorders. In the absence of robust biomarkers for TDP-43, the diagnosis remains primarily based on clinical assessment and neuroimaging. Given the association with psychiatric symptoms, clinical psychiatrists have a key role in the early identification of patients with TDP-43–related diseases. This narrative review provides a comprehensive overview of the pathobiology of TDP-43, resulting clinical presentations, and associated neuropsychiatric manifestations to help guide clinical practice. [ABSTRACT FROM AUTHOR]

To determine the diagnostic accuracy of the intensity of fasciculation evaluated by muscle ultrasound in the differential diagnosis of amyotrophic lateral sclerosis (ALS). We prospectively recruited patients who had ALS and neuropathy-radiculopathy attending Peking Union Medical College Hospital from 2017 to 2020. Healthy adults from a community were recruited as healthy controls. Muscle strength was assessed using the Medical Research Council (MRC) scale. At the first visit to the hospital, patients were assessed for maximal grade of fasciculations, total fasciculation score, and fasciculation grade in 16 muscle groups of bilateral upper and lower limbs using ultrasonography. The sensitivity and specificity of maximal grade of fasciculations, total fasciculation score, and fasciculation grade for the diagnosis of ALS were assessed by receiver operating characteristic analyses. The percentage of limb muscles with a maximal fasciculation grade higher than grade 2 in ALS patients and neuropathy-radiculopathy patients was 84.9% and 9.8%, respectively (χ 2 = 172.436, P < 0.01). Of the 16 limb muscles detected, the total fasciculation score [median (interquartile range)] was 29 (15, 41) in ALS patients and 3 (0, 8) in neuropathy-radiculopathy patients (Z = 9.642, P < 0.001). Remarkable fasciculations were seen in ALS patients whose muscles with a MRC score ranging from 2 to 4, followed by patients with MRC score 5, and then in those with MRC score 0 and 1. The sensitivity and specificity of total fasciculation score for diagnosis of ALS were 80.6% and 93.4%, respectively (cut-off value 14). In patients with ALS, for muscles with MRC score 4 and 5, the percentage of muscles with fasciculation grades ≥ 3 was 42.3% and 24.1% respectively, while in neuropathy-radiculopathy patients, the percentage for muscles with MRC score 4 and 5 was only 1.7% and 0, respectively. A combined analysis of fasciculation intensity and MRC score of the limb muscles may be helpful for differential diagnosis of ALS. [ABSTRACT FROM AUTHOR]

Amyotrophic Lateral Sclerosis (ALS) is the most common motor neuron disease, still incurable. The disease is highly heterogenous both genetically and phenotypically. Therefore, developing efficacious treatments is challenging in many aspects because it is difficult to predict the rate of disease progression and stratify the patients to minimize statistical variability in clinical studies. Moreover, there is a lack of sensitive measures of therapeutic effect to assess whether a pharmacological intervention ameliorates the disease. There is also urgency of markers that reflect a molecular mechanism dysregulated by ALS pathology and can be rescued when a treatment relieves the condition. Here, we summarize and discuss biomarkers tested in multicentered studies and across different laboratories like neurofilaments, the most used marker in ALS clinical studies, neuroinflammatory-related proteins, p75ECD, p-Tau/t-Tau, and UCHL1. We also explore the applicability of muscle proteins and extracellular vesicles as potential biomarkers. • Amyotrophic Lateral Sclerosis (ALS) is the most common motor neuron disease. • There is an urgent need to identify biomarkers for ALS. • Neurofilaments show very good performances for diagnosis and prognosis. • Other markers are under analysis across multiple laboratories for validation. [ABSTRACT FROM AUTHOR]

Epidemiological studies indicate that diabetes increases the risk of Alzheimer's (AD) and Parkinson's (PD) diseases. Conversely, diabetes may confer neuroprotection against amyotrophic lateral sclerosis (ALS) in elderly individuals. Molecular studies have shown that targeting insulin signaling using commonly prescribed antidiabetic drugs and stimulating enzymes in the glycolysis pathway elicits neuroprotection in AD, PD, and ALS. Ongoing clinical trials testing antidiabetic drugs have shown promise in improving cognitive decline and motor function deterioration in patients with AD and PD. Diabetes is associated with an increased risk and progression of Alzheimer's (AD) and Parkinson's (PD) diseases. Conversely, diabetes may confer neuroprotection against amyotrophic lateral sclerosis (ALS). It has been posited that perturbations in glucose and insulin regulation, cholesterol metabolism, and mitochondrial bioenergetics defects may underlie the molecular underpinnings of diabetes effects on the brain. Nevertheless, the precise molecular mechanisms remain elusive. Here, we discuss the evidence from molecular, epidemiological, and clinical studies investigating the impact of diabetes on neurodegeneration and highlight shared dysregulated pathways between these complex comorbidities. We also discuss promising antidiabetic drugs, molecular diagnostics currently in clinical trials, and outstanding questions and challenges for future pursuit. Diabetes is associated with an increased risk and progression of Alzheimer's (AD) and Parkinson's (PD) diseases, the two most common neurodegenerative diseases worldwide. Conversely, diabetes may confer neuroprotection against amyotrophic lateral sclerosis (ALS). It has been posited that perturbations in glucose and insulin regulation, cholesterol metabolism, and mitochondrial bioenergetics defects may underlie the molecular underpinnings of diabetes effects on the brain. Nevertheless, the precise molecular mechanisms remain elusive. Here, we discuss the evidence from molecular, epidemiological, and clinical studies investigating the impact of diabetes on neurodegeneration and highlight shared dysregulated pathways between these complex comorbidities. We also discuss promising antidiabetic drugs, molecular diagnostics currently in clinical trials, and outstanding questions and challenges for future pursuit. [ABSTRACT FROM AUTHOR]

d -Amino acids (d- AAs) form a novel class of vital signaling molecules that control brain homeostasis. Abnormal d -AAs levels in biofluids and tissues occur in various brain disorders. d -AAs can be used as biomarkers for disease diagnosis, prognosis, and treatment monitoring. d -AA signaling and metabolic pathways are promising druggable targets for chronic and acute neuropathologies. Free d -amino acids (d -AAs) are emerging as a novel and important class of signaling molecules in many organs, including the brain and endocrine systems. There has been considerable progress in our understanding of the fundamental roles of these atypical messengers, with increasingly recognized implications in a wide range of neuropathologies, including schizophrenia (SCZ), epilepsy, Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), substance abuse, and chronic pain, among others. Research has enabled the discovery that d -serine, d -aspartate and more recently d -cysteine are essential for the healthy development and function of the central nervous system (CNS). We discuss recent progress that has profoundly transformed our vision of numerous physiological processes but has also shown how d -AAs are now offering therapeutic promise in clinical settings for several human diseases. [ABSTRACT FROM AUTHOR]

• The split-hand index was significantly reduced in ALS using CMAP amplitude, motor unit number index and MScanFit-MUNE methods. • The split-hand index using the CMAP amplitude and MScanFit-MUNE methods exhibited greater diagnostic utility. • The split-hand index using the CMAP amplitude and MScanFit-MUNE methods correlated with measures of functional disability. Utility of the split hand index (SI) in amyotrophic lateral sclerosis (ALS) has been reported when using the compound muscle action potential (CMAP) amplitude method (SI CMAP amp). A motor unit number index (MUNIX) based SI method (SI MUNIX) was purported to exhibit higher sensitivity. The present study assessed the clinical utility of SI, derived by CMAP amplitude, MUNIX and MScan-MUNE (SI MScanFit-MUNE) methods, in ALS. Sixty-two consecutive patients with neuromuscular symptoms (36 ALS and 26 ALS-mimics) were prospectively recruited. The SI was derived by dividing the product of the CMAP amplitude, MUNIX and MScan-MUNE values recorded over first dorsal interosseous and abductor pollicis brevis by values recorded over abductor digit minimi. SI CMAP amp , SI MUNIX and SI MScanFit-MUNE were significantly reduced in ALS, with SI CMAP amp (area under curve (AUC) = 0.801) and SI MScanFit-MUNE (AUC = 0.805) exhibiting greater diagnostic utility than SI MUNIX (AUC = 0.713). SI CMAP amp and SI MScanFit-MUNE exhibited significant correlations with clinical measures of functional disability and weakness of intrinsic hand muscles. SI differentiated ALS from mimic disorders, with SI CMAP amp and SI MScanFit-MUNE exhibiting greater utility. The split hand index represents could serve as a potential diagnostic biomarker in ALS. [ABSTRACT FROM AUTHOR]