Interactive Report: A Top-Down Mechanism for Sporadic ALS Initiated by Ocular Metal Dyshomeostasis and Retrograde Exosomal Transport along t

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The 'top-down' hypothesis is biologically plausible due to shared neuro-developmental origins and transport mechanisms, but current evidence primarily supports the retina as a diagnostic biomarker rather than the initiator of systemic ALS.

Reference [8] View on PubMed →

ID: 33071739 Title: Amyotrophic Lateral Sclerosis: A Neurodegenerative Motor Neuron Disease With Ocular Involvement. Abstract: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that causes degeneration of the lower and upper motor neurons and is the most prevalent motor neuron disease. This disease is characterized by muscle weakness, stiffness, and hyperreflexia. Patients survive for a short period from the onset of the disease. Most cases are sporadic, with only 10% of the cases being genetic. Many genes are now known to be involved in familial ALS cases, including some of the sporadic cases. It has also been observed that, in addition to genetic factors, there are numerous molecular mechanisms involved in these pathologies, such as excitotoxicity, mitochondrial disorders, alterations in axonal transport, oxidative stress, accumulation of misfolded proteins, and neuroinflammation. This pathology affects the motor neurons, the spinal cord, the cerebellum, and the brain, but recently, it has been shown that it also affects the visual system. This impact occurs not only at the level of the oculomotor system but also at the retinal level, which is why the retina is being proposed as a possible biomarker of this pathology. The current review discusses the main aspects mentioned above related to ALS, such as the main genes involved, the most important molecular mechanisms that affect this pathology, its ocular involvement, and the possible usefulness of the retina as a biomarker.

Reference [12] View on PubMed →

ID: 33206086 Title: Manganese-induced neurotoxicity in cerebellar granule neurons due to perturbation of cell network pathways with potential implications for neurodegenerative disorders. Abstract: Manganese (Mn) is essential for living organisms, playing an important role in nervous system function. Nevertheless, chronic and/or acute exposure to this metal, especially during early life stages, can lead to neurotoxicity and dementia by unclear mechanisms. Thus, based on previous works of our group with yeast and zebrafish, we hypothesized that the mechanisms mediating manganese-induced neurotoxicity can be associated with the alteration of protein metabolism. These mechanisms may also depend on the chemical speciation of manganese. Therefore, the current study aimed at investigating the mechanisms mediating the toxic effects of manganese in primary cultures of cerebellar granule neurons (CGNs). By exposing cultured CGNs to different chemical species of manganese ([[2-[(dithiocarboxy)amino]ethyl]carbamodithioato]](2-)-kS,kS']manganese, named maneb (MB), and [[1,2-ethanediylbis[carbamodithioato]](2-)]manganese mixture with [[1,2-ethanediylbis[carbamodithioato]](2-)]zinc, named mancozeb (MZ), and manganese chloride (MnCl2)), and using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, we observed that both MB and MZ induced similar cytotoxicity (LC50∼ 7-9 μM), which was higher than that of MnCl2 (LC50∼ 27 μM). Subsequently, we applied systems biology approaches, including metallomics, proteomics, gene expression and bioinformatics, and revealed that independent of chemical speciation, for non-cytotoxic concentrations (0.3-3 μM), Mn-induced neurotoxicity in CGNs is associated with metal dyshomeostasis and impaired protein metabolism. In this way, we verified that MB induced more post-translational alterations than MnCl2, which can be a plausible explanation for cytotoxic differences between both chemical species. The metabolism of proteins is one of the most energy consuming cellular processes and its impairment appears to be a key event of some cellular stress processes reported separately in other studies such as cell cycle arrest, energy impairment, cell signaling, excitotoxicity, immune response, potential protein accumulation and apoptosis. Interestingly, we verified that Mn-induced neurotoxicity shares pathways associated with the development of Alzheimer's disease, Amyotrophic Lateral Sclerosis, Huntington's disease, and Parkinson's disease. This has been observed in baker's yeast and zebrafish suggesting that the mode of action of Mn may be evolutionarily conserved.

Reference [10] View on PubMed →

ID: 38467696 Title: Evidence for disrupted copper availability in human spinal cord supports CuII(atsm) as a treatment option for sporadic cases of ALS. Abstract: The copper compound CuII(atsm) has progressed to phase 2/3 testing for treatment of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). CuII(atsm) is neuroprotective in mutant SOD1 mouse models of ALS where its activity is ascribed in part to improving availability of essential copper. However, SOD1 mutations cause only ~ 2% of ALS cases and therapeutic relevance of copper availability in sporadic ALS is unresolved. Herein we assessed spinal cord tissue from human cases of sporadic ALS for copper-related changes. We found that when compared to control cases the natural distribution of spinal cord copper was disrupted in sporadic ALS. A standout feature was decreased copper levels in the ventral grey matter, the primary anatomical site of neuronal loss in ALS. Altered expression of genes involved in copper handling indicated disrupted copper availability, and this was evident in decreased copper-dependent ferroxidase activity despite increased abundance of the ferroxidases ceruloplasmin and hephaestin. Mice expressing mutant SOD1 recapitulate salient features of ALS and the unsatiated requirement for copper in these mice is a biochemical target for CuII(atsm). Our results from human spinal cord indicate a therapeutic mechanism of action for CuII(atsm) involving copper availability may also be pertinent to sporadic cases of ALS.

Reference [11] View on PubMed →

ID: 39050823 Title: Copper toxicity and deficiency: the vicious cycle at the core of protein aggregation in ALS. Abstract: The pathophysiology of ALS involves many signs of a disruption in copper homeostasis, with both excess free levels and functional deficiency likely occurring simultaneously. This is crucial, as many important physiological functions are performed by cuproenzymes. While it is unsurprising that many ALS symptoms are related to signs of copper deficiency, resulting in vascular, antioxidant system and mitochondrial oxidative respiration deficiencies, there are also signs of copper toxicity such as ROS generation and enhanced protein aggregation. We discuss how copper also plays a key role in proteostasis and interacts either directly or indirectly with many of the key aggregate-prone proteins implicated in ALS, such as TDP-43, C9ORF72, SOD1 and FUS as well as the effect of their aggregation on copper homeostasis. We suggest that loss of cuproprotein function is at the core of ALS pathology, a condition that is driven by a combination of unbound copper and ROS that can either initiate and/or accelerate protein aggregation. This could trigger a positive feedback cycle whereby protein aggregates trigger the aggregation of other proteins in a chain reaction that eventually captures elements of the proteostatic mechanisms in place to counteract them. The end result is an abundance of aggregated non-functional cuproproteins and chaperones alongside depleted intracellular copper stores, resulting in a general lack of cuproenzyme function. We then discuss the possible aetiology of ALS and illustrate how strong risk factors including environmental toxins such as BMAA and heavy metals can functionally behave to promote protein aggregation and disturb copper metabolism that likely drives this vicious cycle in sporadic ALS. From this synthesis, we propose restoration of copper balance using copper delivery agents in combination with chaperones/chaperone mimetics, perhaps in conjunction with the neuroprotective amino acid serine, as a promising strategy in the treatment of this incurable disease.

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ID: 39955442 Title: Extracellular vesicles efficiently deliver survival motor neuron protein to cells in culture. Abstract: Spinal Muscular Atrophy (SMA) is a genetic neuromuscular disorder caused by homozygous mutation or deletion of the survival motor neuron 1 (SMN1) gene, leading to a low quantity of SMN protein in cells. This depletion of SMN protein preferentially leads to death of motor neurons and, consequently, muscle atrophy, in addition to defects in many other peripheral tissues. SMN protein is naturally loaded into extracellular vesicles (EVs), which are sub-micron-sized, membrane-bound particles released from all cell types. The innate ability of EVs to deliver cargo to recipient cells has caused these vesicles to gain interest as therapeutic delivery vehicles. In this study, we show that adenovirus-mediated overexpression of SMN protein in HepG2 cells leads to the release of EVs loaded with high levels of SMN protein into conditioned medium. Application of this medium to recipient cells in tissue culture led to uptake of the SMN protein, which subsequently transited to the nucleus and co-localized with Gemin2 protein, forming nuclear gem-like structures similar to the native SMN protein. Overall, this work demonstrates that SMN protein can be delivered to cells through EVs, which holds promise as a potential therapy for patients with SMA.

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ID: 40306255 Title: Retinal alterations induced by amyotrophic lateral sclerosis: An analysis using optical coherence tomography. Abstract: In this study, we aimed to investigate retinal changes in a large cohort of amyotrophic lateral sclerosis (ALS) patients and healthy controls (HCs) to further elucidate their relationship with ALS. This was a cross-sectional observational study. We evaluated retinal layer thickness in 134 ALS patients and 66 HCs using optical coherence tomography (OCT). Particularly, we focused on the macular region and peripapillary retinal nerve fiber layer (p-RNFL). The examination of retinal layers in ALS patients revealed a significant change in the inner nuclear layer (INL), with a pattern of initial thickening followed by thinning, which correlated with disease stages, most notably in the inner nasal quadrant. Moreover, the p-RNFL in the temporal quadrant was thinner in ALS patients compared to HCs. In addition, ALS patients who developed bulbar symptoms exhibited marginally thinner p-RNFL in the temporal quadrant compared to those without bulbar symptoms. Interestingly, a thinner p-RNFL in the temporal quadrant did not correlate with faster disease progression. This study reveals notable changes in the INL and p-RNFL thickness in ALS patients, highlighting the intricate relationship between retinal changes and ALS progression. Despite these retinal alterations, no correlation with disease progression rate was observed. These findings suggest that while OCT shows potential in monitoring ALS, its role in predicting disease course requires further investigation with long-term longitudinal studies and diverse patient cohorts.

Reference [9] View on PubMed →

ID: 40340620 Title: Exploring oculomotor challenges in amyotrophic lateral sclerosis: a comprehensive review. Abstract: Traditionally understood as a motor neuron disease, amyotrophic lateral sclerosis (ALS) is now recognized to involve broader neurodegenerative processes, including the oculomotor system. This narrative review summarizes current evidence on oculomotor dysfunction in ALS, with a focus on its relationship to disease-related motor and cognitive impairments. Specifically, the review examines key eye-tracking (ET) metrics, including saccades, smooth pursuit, and fixation, highlighting their potential to reflect both motor and extramotor degeneration. Notably, patients with bulbar-onset ALS exhibit more pronounced oculomotor impairments. By synthesizing findings on the connection between oculomotor dysfunction and cognitive decline, this review underscores the potential of ET as a noninvasive tool for assessing ALS progression. Oculomotor metrics, as part of a broader understanding of ALS's impact on multiple neural networks, may offer valuable insights to refine patient assessment and care strategies, particularly in advanced disease stages.

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ID: 40350723 Title: [Oculomotor disorders in patients with amyotrophic lateral sclerosis]. Abstract: Oculomotor disorders are not typical manifestations of amyotrophic lateral sclerosis (ALS). Occasionally, this disease is associated with vertical gaze paresis, presenting a distinct type as «ALS+progressive supranuclear palsy». Studies using eye-tracking methods have revealed a variety of subclinical oculomotor disorders in this disease. These disorders can manifest as changes in reflex and voluntary saccades, antisaccades, smooth tracking eye movements, and fixations. A significant association between oculomotor disorders and clinical manifestations of ALS was reported. The occurrence of oculomotor disorders indicates the involvement of broader neuroanatomical structures, including the prefrontal cortex and basal ganglia. The lack of consistency in the data from different studies and their limited number emphasize the need for further research in this area. Глазодвигательные нарушения не являются характерными симптомами бокового амиотрофического склероза (БАС). Изредка наблюдаются случаи развития пареза вертикального взора при данном заболевании. В таких случаях говорят об особом варианте «БАС-прогрессирующий надъядерный паралич». Исследования с использованием трекинга глаз выявили разнообразные субклинические глазодвигательные нарушения при данном заболевании. Эти расстройства могут проявляться в виде изменения рефлекторных и произвольных саккад, антисаккад, плавных следящих движений глаз и фиксаций. Выявлена значительная связь между глазодвигательными нарушениями и клиническими проявлениями БАС. Развитие глазодвигательных нарушений указывает на вовлечение более широких нейроанатомических структур, включая префронтальную кору и базальные ганглии. Отсутствие согласованности в данных различных исследований и их ограниченное количество подчеркивают необходимость дальнейших исследований в этой области.

Reference [6] View on PubMed →

ID: 40560963 Title: Analysis of retinal markers and incident amyotrophic lateral sclerosis: An optical coherence tomography-based cohort study. Abstract: Biomarkers are widely recognized as crucial breakthroughs in tackling amyotrophic lateral sclerosis (ALS). Among them, retina markers may hold promise due to the close retina-brain connection and non-invasive, portable detection methods. Thus, using optical coherence tomography (OCT), we investigated the link between baseline cell-level retinal features and future ALS risk. Participants from the UK Biobank underwent OCT scans to assess retinal layers, macula, and optic disc parameters. Follow-up commenced two years after the baseline period (2006-2010), during which ALS cases were identified using International Classification of Diseases (ICD) codes from medical and assessment records. Cox proportional hazards models were applied to examine the relationship between retinal markers and incident ALS. Over a median follow-up of 14.11 years, 70 ALS cases occurred among 53,824 participants (incidence 10.58 per 100,000 person-years). Most participants were White (94.6%), 44.8% male, with a median age of 58 years. After adjusting for demographics and comorbidities affecting the retina, a standard deviation (SD) decrease of 15.19 µm in photoreceptor layer (PRL) thickness was associated with a 19% (95% confidence interval [7, 29]; p = 0.002) increased risk of ALS, while a SD increase of 26.11 µm in retinal pigment epithelium (RPE) thickness corresponded to a 20% (95% CI [7, 34]; p = 0.002) higher risk. Sensitivity analyses excluding follow-ups of less than 4 and 6 years yielded consistent results. Subgroup analyses showed these findings were more pronounced in smokers. The main limitation of this study is its single time point observational design. A thinner PRL and thicker RPE may precede the clinical diagnosis of ALS, offering potential clues for early diagnosis and insights into the disease's pathogenesis.

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ID: 40625857 Title: A Novel Retinal Nerve Fiber Layer Biomarker of Amyotrophic Lateral Sclerosis (ALS) Identified Using Longitudinal in vivo Ocular Imaging. Abstract: Like motor neurons, retinal ganglion cells (RGCs) have long axons and high metabolic demands, making them vulnerable to disruption of axonal transport. Unlike motor neurons, the RGC axons are accessible to high-resolution non-invasive optical imaging in their intraocular portion. A non-invasive in vivo retinal imaging biomarker can be valuable for amyotrophic lateral sclerosis (ALS) diagnosis and monitoring. We aim to assess the presence of inner retinal pathology in a mouse model of ALS and its possible progression with age. Transgenic SOD1G93A mice (n=8, 4M/4F) and age-matched controls (n=8, 4M/4F) underwent in vivo retinal imaging with confocal scanning laser ophthalmoscopy (cSLO) coupled with optical coherence tomography (OCT) at 20 weeks of age. Another group of SOD1G93A mice (n=20, 6M/14F) and age-matched controls (n=20, 6M/14F) underwent longitudinal in vivo retinal imaging with the same device. Each retinal imaging session included infrared reflectance (IR) and blue reflectance (BR) cSLO coupled with OCT. Hyperreflective puncta located in the retinal nerve fiber layer (RNFL) were counted in a blinded fashion in ALS and control mice. The number of puncta at 20 weeks of age in ALS mice was compared with controls using Wilcoxon test. The rates of increase of puncta number were analyzed using a Generalized Linear Mixed-Effect Model (GLMM) for genotype, time, and sex. IR-cSLO coupled with OCT revealed hyperreflective puncta located in the RNFL of ALS mice. IR-cSLO fundus imaging at the age of 20 weeks showed ALS mice had significantly higher number of puncta compared to controls (2.1±2.3 vs 0.5±0.8; (mean±SD), respectively, p=0.036). GLMM analysis showed both ALS mutation and age were significantly associated with the rate of increase of puncta number (p=0.000232 and p=0.000366, respectively). In addition, female ALS mice had a steeper increase of puncta compared to male ALS mice (0.21±0.04 log number puncta/week vs 0.16±0.04, respectively; p=0.037). Our findings demonstrate distinct inner retinal nerve fiber layer pathology, detected using cSLO coupled with OCT, which worsens over time. These findings support the potential of retinal imaging as a translationally relevant, non-invasive biomarker for ALS diagnosis or disease monitoring in humans.

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ID: 40698100 Title: Ganglion Cell Layer Thickness as a Biomarker for Amyotrophic Lateral Sclerosis Functional Outcome: An OCT study. Abstract: This study aims to evaluate various optical coherence tomography (OCT) parameters in patients diagnosed with amyotrophic lateral sclerosis (ALS). Assessment of BCVA was done using Snellen charts, and subjective refraction was done to achieve a BCVA for distance and near. Measurement of intraocular pressure (IOP) was done with Goldman applanation tonometry. Stereoscopic fundus examination was performed using a 90D lens to assess the status of the optic nerve and retina, ruling out any ocular pathology. The patients were then subjected to OCT scanning to measure optic nerve head and macular parameters. Optical coherence tomography was performed using CIRRUS™ HD OCT (500-21822) (version 8.0.0.518) (Carl Zeiss Meditec, Dublin, CA, USA). The analyzed area was centered manually, and the absence of segmentation errors was confirmed for each scan. RE Avg RNFL and LE Avg RNFL showed weak correlations with ALSFRS, indicated by Pearson Correlation coefficients of 0.073 and -0.026, respectively. The p-values (0.637 and 0.86) suggested that these correlations were not statistically significant. RE Avg GCL and LE Avg GCL, on the other hand, exhibited moderate positive correlations with ALSFRS scores, with correlation coefficients of 0.337 (RE) and 0.389 (LE). These correlations were statistically significant, as indicated by p-values of 0.021 and 0.006, respectively, suggesting a substantial association between GCL thickness and ALS functional outcomes. All patients in our study were clinically diagnosed cases of ALS, as per the El Escorial criteria. Age group-wise analysis showed statistically significant thinning overall as well as quadrant-wise RNFL parameters in patients less than 50 years compared to age-matched controls, indicating that the pathological process occurring in larger motor neurons in ALS might also be happening in smaller sensory neurons of the retina, causing thinning, which was not due to age-related process. Although GCIPL thinning was occurring in our cases, though statistically not significant compared to control, the significant positive correlation observed between GCIPL and ALS functional outcome and between RNFL and GCIPL measurements highlighted the fact that though the axonal degeneration in retinal neurons might not be translating to the same extent in ganglion cells in ALS, the subtle thinning of GCIPL correlated strongly with functional disability in patients with ALS, implying better functional scores with higher values of GCIPL parameters. In summary, GCL measurements in both eyes showed a notable relationship with ALSFRS, whereas RNFL did not appear to correlate significantly.

Reference [13] View on PubMed →

ID: 40894549 Title: Lead (Pb) exposure results in cell type specific changes in the mouse retina and optic nerve. Abstract: Chronic exposure to lead (Pb) is known to cause deficits in neuronal function across the nervous system, including the visual nervous system. Visual deficits have been observed in both humans and rodent models following Pb exposure. However, how Pb exposure causes visual deficits is poorly understood. In this study, we evaluated the effects of Pb toxicity on the retina and optic nerve of the mouse visual nervous system. We used C57BL/6 adult mice of both sexes and divided them into one of three different exposure groups. Adult mice received daily oral gavage of 108mg/kg Na-acetate (control), 54mg/kg Pb-acetate (low dose), or 108mg/kg Pb-acetate (high dose) for 4 weeks. At the end of Pb exposure, whole blood, retina, and optic nerve samples were collected for Pb quantification by atomic absorption spectroscopy and tissue immunohistochemical analyses. Cell type specific markers were used to quantify changes in cell density of retinal ganglion cells (RGCs), oligodendrocytes (OLs), oligodendrocyte precursor cells (OPCs), and myelin structure. Following Pb exposure, we observed a small, but significant reduction in the cell density of RGCs in the retina. However, we found no significant changes in branch thickness or coverage of retinal vasculature following Pb exposure. In the optic nerve after Pb exposure, we found a significant reduction in the cell density of OLs and OPCs. Finally, using immunolabeling for Caspr and Nav1.6, we observed significant structural changes in nodes of Ranvier, suggesting a disruption in myelin structure. Our findings suggested that Pb toxicity may impair survival and maturation process of oligodendrocytes, changes in myelin structures, and potential demyelination of the optic nerve. These results provide the foundation for future investigations into the molecular mechanisms of Pb-dependent changes in myelination and visual nervous system function.

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ID: 41651252 Title: Novel extracellular vesicle release pathway facilitated by toxic superoxide dismutase 1 oligomers. Abstract: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that results in paralysis and death within three to five years. Mutations in over forty different proteins have been linked to ALS, raising debate over whether ALS is a single disease or multiple disorders with similar symptoms. Mutations in Cu,Zn superoxide dismutase 1 (SOD1) are found in only 2-3% of ALS cases, yet misfolded SOD1 appears in both sporadic (sALS) and familial (fALS) patients. Furthermore, mutations in TDP-43 or FUS increase levels of misfolded SOD1 on extracellular vesicles (EVs). Small EVs isolated from ALS patient samples have been shown to cause death of wild-type motor neurons and myotubes, supporting the theory that EVs play a role in spreading disease. We hypothesize that the previously identified toxic trimeric SOD1 spreads via EVs in ALS and influences the distribution of other ALS-related proteins, suggesting a common mechanism. To test this, we isolate EVs from motor neuron-like cells expressing mutations that stabilize trimers. We then perform a sandwich enzyme-linked immunosorbent assay (ELISA) using a CD9 capture antibody to measure whether misfolded SOD1 and 17 other ALS-related proteins increase or decrease on EVs with trimer stabilization. We identify which EV release pathway is affected by trimeric SOD1 using endocytosis and exocytosis inhibitors and analyze altered protein interaction pathways through co-immunoprecipitation and mass spectrometry proteomics. Our results show that VAPB, VCP, and Stathmin-2 increase on EVs when trimers are stabilized. The common pathway linking these ALS-associated proteins and SOD1 appears to involve multiple mechanisms, including the Caveolae endocytosis pathway, pointing to a novel hybrid EV release pathway in ALS. Overall, our findings show that trimeric SOD1 influences EV cargo and spread in ALS.

Reference [19] View on PubMed →

ID: 41672113 Title: Superoxide dismutase impacts extracellular vesicle shedding and uptake. Abstract: Extracellular vesicles (EVs), which transfer bioactive macromolecules between cells, play a critical role in the pathogenesis of multiple neurodegenerative diseases. Focus has centered on how altered EV contents propagate disease and on the potential for EVs as diagnostic biomarkers, while the effects of pathogenic factors on EV release are poorly understood. Using a functional endogenous reporter, we showed that the key antioxidant enzyme superoxide dismutase 1 (SOD-1) is expressed in C. elegans EV-releasing neurons, localizes to the cytoplasm, and reduces levels of reactive oxygen species (ROS). We then defined how sod-1 mutations affect EV shedding from sensory neuron primary cilia into the environment, ciliary enrichment of proteins packaged into EVs, and glial uptake of EVs in vivo, by imaging C. elegans expressing fluorescent protein-tagged EV cargoes. Deletion of SOD-1, as well as the SOD-1(G85R) amyotrophic lateral sclerosis (ALS) pathogenic variant, increased EV shedding from the cilium distal tip, and this was associated with greater abundance of EV cargo in this ciliary compartment. In contrast, loss of SOD-1 reduced the glial uptake of a different EV subpopulation that is shed from the ciliary base, without affecting release into the environment. These results demonstrate that SOD-1 has a subtype-specific effect on the release of EVs with distinct signaling potentials. Intriguingly, we discovered that exposure to paraquat, which increases mitochondrial ROS, reduced the shedding of both distal tip and ciliary base-derived EVs. These opposing effects of the sod-1 mutations and paraquat treatment on EV release suggest that ROS in distinct subcellular compartments may differentially impact ciliary EV shedding.

Reference [18] View on PubMed →

ID: 42097486 Title: Conjecture for a free radical epimerization process in Alzheimer, Parkinson, Lewy body, amyotrophic lateral sclerosis, progressive Supranuclear Palsy and Creutzfeldt Jakob diseases. Abstract: Brain protease-resistant misfolded proteins have been described in Alzheimer (AD), Parkinson (PD), Lewy Body (LBD), Amyotrophic Lateral Sclerosis (ALS), Progressive Supranuclear Palsy (PSP) and Creutzfeldt Jakob (CJD) diseases. The role of free radicals in generating these protease resistant structures has been experimentally demonstrated in prion bovine spongiform encephalopathy (BSE), when manganese is substituted for copper (Cu), in bovine brain homogenates in reductive medium, while Cu protective effect against free radicals can be restored by Cu supplementation in oxidative medium. These facts can suggest a free radical-induced epimerization process in neuroprotein misfolding leading to the transformation of physiological L-amino acid brain proteins into abnormal D-structures which will be deposited in the brain as observed in neurodegenerative diseased brains. A blood Cu increase, not ceruloplasmin (CP) bound correlated with a Cu increase in the cerebrospinal fluid (CSF) and a Cu decrease in the brain have been described in AD, PD, ALS, or CJD. This indicates that following neuronal death, Cu might be expelled from brain proteins and subsequent to redistribution between brain, CSF and blood, it will result a brain Cu deficiency and a decrease in Cu brain protection against free radicals. In the aim of repairing this deficiency and slow down the neurodegenerative disease process, a brain Cu complexes vectorization through the blood-brain barrier might restore brain Cu homeostasis.

Reference [17] View on PubMed →

ID: 42156174 Title: COMMD1 Induces Copper Deficiency of SOD1 by Inhibiting the Palmitoylation of CCS in ALS. Abstract: Mutations in superoxide dismutase 1 (SOD1) compromise its metal-binding capacity, resulting in protein misfolding and aggregation, which ultimately induces cellular apoptosis in amyotrophic lateral sclerosis (ALS). Copper metabolism domain containing 1 (COMMD1), a gene implicated in copper homeostasis, has not been thoroughly characterized in the context of ALS pathogenesis. In this study, we identified elevated COMMD1 expression in ALS, potentially contributing to diminished copper incorporation into SOD1. Knockdown of COMMD1 enhanced palmitoylation of the copper chaperone for SOD1 (CCS), facilitating its membrane translocation and promoting copper loading into SOD1, thereby conferring neuroprotection in ALS. Mechanistically, we established that COMMD1 knockdown augments CCS palmitoylation via activation of the hypoxia-inducible factor 1 subunit alpha (HIF-1α)/fatty acid synthase (FASN) signaling axis. In vivo investigations utilizing male hSOD1G93A transgenic mice demonstrated that COMMD1 deficiency markedly ameliorated the deterioration of motor function and prolonged survival duration. These findings collectively suggest that COMMD1 represents a potential therapeutic target for ALS intervention.

Reference [20] View on PubMed →

ID: 42304926 Title: Linking Neurodegeneration and Age-related Macular Degeneration: Unified Pathways and Intervention Strategies. Abstract: Age-related macular degeneration (AMD) is caused by the degeneration of photoreceptors and retinal pigment epithelium (RPE) along with drusen deposition and is the leading cause of vision loss in older adults. Both these structures within the central nervous system (CNS) utilize common neuro-inflammatory mechanisms because the retina is an outgrowth of the brain. Like the brain, the eye has its own physical characteristics and surface molecules as well as a tendency towards specific immune reactions. Numerous distinct neurodegenerative diseases like Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), and Frontotemporal dementia (FTD) that impact the brain present as eye symptoms, and the conventional diagnosis of these neurodegenerative disorders (NDs) is often preceded by ocular symptoms. Furthermore, several eye-specific disorders have characteristics in common with other CNS disorders. NDs and AMD share common key features, such as tau and amyloid-β deposits, oxidative stress response, chronic inflammation, and dysregulation of microglia and müller glia. Common pathological mechanisms include complement activation, amyloid aggregation, neuroinflammation, vascular impairment, and cell death, providing a basis for a convergent neuroimmune axis between retinal and cerebral degeneration. Comparing these age-related diseases will facilitate the identification of shared risk factors, convergent molecular pathways, and potential cross-applicable therapeutic strategies, such as anti-inflammatory, anti-complementary, anti-apoptotic, and anti-VEGF-based approaches. This knowledge may enhance understanding of neurodegenerative diseases, help identify early biomarker development for diagnosis, and enable the design of targeted therapeutic strategies.

Reference [15] View on PubMed →

ID: 42351263 Title: Dynamic integration of skeletal muscle signals via extracellular vesicles in motor neuron diseases. Abstract: Extracellular vesicles (EVs) are heterogenous lipid bilayer-enclosed particles secreted by virtually all cell types. They encapsulate a diverse array of bioactive molecules, including proteins, lipids, nucleic acids, and metabolites, which can be transferred to recipient cells, thereby modulating their function and phenotype. In recent years, skeletal muscle-derived EVs (SkM-EVs) have emerged as key players in the bidirectional communication between skeletal muscle and motor neurons, contributing to the establishment and maintenance of neuromuscular homeostasis. Disruptions in this intercellular signalling have been implicated in the pathophysiology of motor neuron diseases (MNDs) such as spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS). In these contexts, SkM-EVs may contribute to disease progression by delivering pathogenic cargo, including misfolded proteins and aberrant RNAs, to motor neurons. A comprehensive understanding of SkM-EV biology, particularly their roles in neuromuscular communication, could offer critical insights into disease mechanisms and identify novel opportunities for biomarker discovery and therapeutic intervention. This review synthesizes current knowledge on the functional roles of SkM-EVs in motor neuron health and disease and evaluates their potential as diagnostic tools and therapeutic vectors in the context of MNDs.

Reference [2] View on PubMed →

ID: 42512084 Title: Retinal Thickness and Vascular Density Changes in Amyotrophic Lateral Sclerosis Assessed by Optical Coherence Tomography Angiography. Abstract: Background: Amyotrophic lateral sclerosis (ALS) is increasingly recognized as a multisystem disorder involving neurovascular dysfunction. The retina allows in vivo assessment of neurovascular changes. This study evaluated retinal structural and microvascular alterations in ALS using optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A). Methods: This cross-sectional study included 46 participants with ALS and 19 healthy controls. Retinal thickness and vascular density in the superficial and deep retinal capillary plexuses and the choriocapillaris were quantified using OCT and OCT-A. Group comparisons and logistic regression analyses were performed to assess associations with ALS. Subgroup analyses were conducted according to clinical phenotype. Results: In total, 124 eyes were analyzed. ALS was associated with increased average retinal thickness (p = 0.023) and reduced vascular density in the superficial retinal capillary plexus (p = 0.005), deep retinal capillary plexus (p < 0.001), and choriocapillaris (p = 0.004). In logistic regression analyses, retinal thickness was positively associated with ALS status (OR = 1.42, p = 0.023), whereas higher vascular density in the superficial plexus, deep plexus, and choriocapillaris was associated with lower odds of ALS. No significant differences were observed between bulbar- and spinal-onset ALS phenotypes. Conclusions: ALS is associated with structural and microvascular retinal alterations detectable by OCT and OCT-A. These findings support the presence of systemic neurovascular dysfunction and highlight retinal imaging as a promising, non-invasive approach for investigating disease mechanisms and developing potential biomarkers.

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ID: 42526365 Title: A systematic review and meta-analysis of OCT-based ophthalmic changes in amyotrophic lateral sclerosis. Abstract: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease marked by motor decline and respiratory failure. Optical coherence tomography (OCT), a non-invasive imaging technique, has been explored for detecting retinal structural changes that may reflect neurodegeneration in ALS. While some studies report thinning of retinal layers, findings remain inconsistent. Therefore, a meta-analysis is needed to clarify the extent of retinal involvement and the potential of OCT as a biomarker in ALS. A systematic literature search was conducted across PubMed, EMBASE, and Cochrane databases for studies published between 2010 and May 2025. Study quality was assessed using the Newcastle-Ottawa Scale (NOS), and publication bias was evaluated through funnel plot asymmetry and Egger's test. Pooled effect sizes were calculated using random-effects models to account for between-study heterogeneity, and differences in OCT parameters between ALS patients and healthy controls were expressed as standardized mean differences (SMD) with 95% confidence intervals (CI). Statistical heterogeneity was quantified using the I2 statistic. A total of 17 studies were included in the present meta-analysis. The primary unadjusted global model demonstrated significant reduction of retinal nerve fibre layer (RNFL) thickness in ALS patients compared to controls (unadjusted SMD = -0.295, 95% CI: -0.522, -0.068). Upon applying a Design Effect variance inflation model to address fellow-eye non-independence, the pooled estimate remained robustly significant across a conservative range of intraclass correlations (SMD ranged from -0.256 to -0.249). Subgroup analyses revealed that RNFL thinning was particularly pronounced in spinal-onset ALS (SMD = -0.54, 95% CI: (-0.98, -0.10). When studies were stratified by the region of conduct, RNFL and macular thinning reached statistical significance only within the non-Asian subgroup, though the formal test for subgroup differences was not significant. This meta-analysis demonstrates significant bilateral RNFL thinning in ALS, with relative preservation of the Inner Nuclear Layer and Ganglion Cell Layer - Inner Plexiform Layer, supporting retinal neurodegeneration as a feature of this multisystem disorder. PROSPERO identifier CRD420251076035.

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