ID: 27056981
Title: Axonal transport defects are a common phenotype in Drosophila models of ALS.
Abstract: Amyotrophic lateral sclerosis (ALS) is characterized by the degeneration of motor neurons resulting in a catastrophic loss of motor function. Current therapies are severely limited owing to a poor mechanistic understanding of the pathobiology. Mutations in a large number of genes have now been linked to ALS, including SOD1, TARDBP (TDP-43), FUS and C9orf72. Functional analyses of these genes and their pathogenic mutations have provided great insights into the underlying disease mechanisms. Defective axonal transport is hypothesized to be a key factor in the selective vulnerability of motor nerves due to their extraordinary length and evidence that ALS occurs as a distal axonopathy. Axonal transport is seen as an early pathogenic event that precedes cell loss and clinical symptoms and so represents an upstream mechanism for therapeutic targeting. Studies have begun to describe the impact of a few pathogenic mutations on axonal transport but a broad survey across a range of models and cargos is warranted. Here, we assessed the axonal transport of different cargos in multiple Drosophila models of ALS. We found that axonal transport defects are common across all models tested, although they often showed a differential effect between mitochondria and vesicle cargos. Motor deficits were also common across the models and generally worsened with age, though surprisingly there was not a clear correlation between the severity of axonal transport defects and motor ability. These results further support defects in axonal transport as a common factor in models of ALS that may contribute to the pathogenic process.

ID: 33837088
Title: C9orf72-derived arginine-containing dipeptide repeats associate with axonal transport machinery and impede microtubule-based motility.
Abstract: A hexanucleotide repeat expansion in the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). How this mutation leads to these neurodegenerative diseases remains unclear. Here, we show using patient stem cell-derived motor neurons that the repeat expansion impairs microtubule-based transport, a process critical for neuronal survival. Cargo transport defects are recapitulated by treating neurons from healthy individuals with proline-arginine and glycine-arginine dipeptide repeats (DPRs) produced from the repeat expansion. Both arginine-rich DPRs similarly inhibit axonal trafficking in adult Drosophila neurons in vivo. Physical interaction studies demonstrate that arginine-rich DPRs associate with motor complexes and the unstructured tubulin tails of microtubules. Single-molecule imaging reveals that microtubule-bound arginine-rich DPRs directly impede translocation of purified dynein and kinesin-1 motor complexes. Collectively, our study implicates inhibitory interactions of arginine-rich DPRs with axonal transport machinery in C9orf72-associated ALS/FTD and thereby points to potential therapeutic strategies.

ID: 34190355
Title: A CRMP4-dependent retrograde axon-to-soma death signal in amyotrophic lateral sclerosis.
Abstract: Amyotrophic lateral sclerosis (ALS) is a fatal non-cell-autonomous neurodegenerative disease characterized by the loss of motor neurons (MNs). Mutations in CRMP4 are associated with ALS in patients, and elevated levels of CRMP4 are suggested to affect MN health in the SOD1G93A -ALS mouse model. However, the mechanism by which CRMP4 mediates toxicity in ALS MNs is poorly understood. Here, by using tissue from human patients with sporadic ALS, MNs derived from C9orf72-mutant patients, and the SOD1G93A -ALS mouse model, we demonstrate that subcellular changes in CRMP4 levels promote MN loss in ALS. First, we show that while expression of CRMP4 protein is increased in cell bodies of ALS-affected MN, CRMP4 levels are decreased in the distal axons. Cellular mislocalization of CRMP4 is caused by increased interaction with the retrograde motor protein, dynein, which mediates CRMP4 transport from distal axons to the soma and thereby promotes MN loss. Blocking the CRMP4-dynein interaction reduces MN loss in human-derived MNs (C9orf72) and in ALS model mice. Thus, we demonstrate a novel CRMP4-dependent retrograde death signal that underlies MN loss in ALS.

ID: 34303705
Title: Development of a specific live-cell assay for native autophagic flux.
Abstract: Autophagy is an evolutionarily conserved pathway mediating the breakdown of cellular proteins and organelles. Emphasizing its pivotal nature, autophagy dysfunction contributes to many diseases; nevertheless, development of effective autophagy modulating drugs is hampered by fundamental deficiencies in available methods for measuring autophagic activity or flux. To overcome these limitations, we introduced the photoconvertible protein Dendra2 into the MAP1LC3B locus of human cells via CRISPR/Cas9 genome editing, enabling accurate and sensitive assessments of autophagy in living cells by optical pulse labeling. We used this assay to perform high-throughput drug screens of four chemical libraries comprising over 30,000 diverse compounds, identifying several clinically relevant drugs and novel autophagy modulators. A select series of candidate compounds also modulated autophagy flux in human motor neurons modified by CRISPR/Cas9 to express GFP-labeled LC3. Using automated microscopy, we tested the therapeutic potential of autophagy induction in several distinct neuronal models of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In doing so, we found that autophagy induction exhibited discordant effects, improving survival in disease models involving the RNA binding protein TDP-43, while exacerbating toxicity in neurons expressing mutant forms of UBQLN2 and C9ORF72 associated with familial ALS/FTD. These studies confirm the utility of the Dendra2-LC3 assay, while illustrating the contradictory effects of autophagy induction in different ALS/FTD subtypes.

ID: 35026048
Title: Disruption of ER-mitochondria tethering and signalling in C9orf72-associated amyotrophic lateral sclerosis and frontotemporal dementia.
Abstract: Hexanucleotide repeat expansions in C9orf72 are the most common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The mechanisms by which the expansions cause disease are not properly understood but a favoured route involves its translation into dipeptide repeat (DPR) polypeptides, some of which are neurotoxic. However, the precise targets for mutant C9orf72 and DPR toxicity are not fully clear, and damage to several neuronal functions has been described. Many of these functions are regulated by signalling between the endoplasmic reticulum (ER) and mitochondria. ER-mitochondria signalling requires close physical contacts between the two organelles that are mediated by the VAPB-PTPIP51 'tethering' proteins. Here, we show that ER-mitochondria signalling and the VAPB-PTPIP51 tethers are disrupted in neurons derived from induced pluripotent stem (iPS) cells from patients carrying ALS/FTD pathogenic C9orf72 expansions and in affected neurons in mutant C9orf72 transgenic mice. In these mice, disruption of the VAPB-PTPIP51 tethers occurs prior to disease onset suggesting that it contributes to the pathogenic process. We also show that neurotoxic DPRs disrupt the VAPB-PTPIP51 interaction and ER-mitochondria contacts and that this may involve activation of glycogen synthase kinases-3β (GSK3β), a known negative regulator of VAPB-PTPIP51 binding. Finally, we show that these DPRs disrupt delivery of Ca2+ from ER stores to mitochondria, which is a primary function of the VAPB-PTPIP51 tethers. This delivery regulates a number of key neuronal functions that are damaged in ALS/FTD including bioenergetics, autophagy and synaptic function. Our findings reveal a new molecular target for mutant C9orf72-mediated toxicity.

ID: 35691950
Title: Genetics of amyotrophic lateral sclerosis: seeking therapeutic targets in the era of gene therapy.
Abstract: Amyotrophic lateral sclerosis (ALS) is an intractable disease that causes respiratory failure leading to mortality. The main locus of ALS is motor neurons. The success of antisense oligonucleotide (ASO) therapy in spinal muscular atrophy (SMA), a motor neuron disease, has triggered a paradigm shift in developing ALS therapies. The causative genes of ALS and disease-modifying genes, including those of sporadic ALS, have been identified one after another. Thus, the freedom of target choice for gene therapy has expanded by ASO strategy, leading to new avenues for therapeutic development. Tofersen for superoxide dismutase 1 (SOD1) was a pioneer in developing ASO for ALS. Improving protocols and devising early interventions for the disease are vital. In this review, we updated the knowledge of causative genes in ALS. We summarized the genetic mutations identified in familial ALS and their clinical features, focusing on SOD1, fused in sarcoma (FUS), and transacting response DNA-binding protein. The frequency of the C9ORF72 mutation is low in Japan, unlike in Europe and the United States, while SOD1 and FUS are more common, indicating that the target mutations for gene therapy vary by ethnicity. A genome-wide association study has revealed disease-modifying genes, which could be the novel target of gene therapy. The current status and prospects of gene therapy development were discussed, including ethical issues. Furthermore, we discussed the potential of axonal pathology as new therapeutic targets of ALS from the perspective of early intervention, including intra-axonal transcription factors, neuromuscular junction disconnection, dysregulated local translation, abnormal protein degradation, mitochondrial pathology, impaired axonal transport, aberrant cytoskeleton, and axon branching. We simultaneously discuss important pathological states of cell bodies: persistent stress granules, disrupted nucleocytoplasmic transport, and cryptic splicing. The development of gene therapy based on the elucidation of disease-modifying genes and early intervention in molecular pathology is expected to become an important therapeutic strategy in ALS.

ID: 36261266
Title: Loss of Activity-Induced Mitochondrial ATP Production Underlies the Synaptic Defects in a Drosophila Model of ALS.
Abstract: Mutations in the gene encoding vesicle-associated membrane protein B (VAPB) cause a familial form of amyotrophic lateral sclerosis (ALS). Expression of an ALS-related variant of vapb (vapbP58S ) in Drosophila motor neurons results in morphologic changes at the larval neuromuscular junction (NMJ) characterized by the appearance of fewer, but larger, presynaptic boutons. Although diminished microtubule stability is known to underlie these morphologic changes, a mechanism for the loss of presynaptic microtubules has been lacking. By studying flies of both sexes, we demonstrate the suppression of vapbP58S -induced changes in NMJ morphology by either a loss of endoplasmic reticulum (ER) Ca2+ release channels or the inhibition Ca2+/calmodulin (CaM)-activated kinase II (CaMKII). These data suggest that decreased stability of presynaptic microtubules at vapbP58S NMJs results from hyperactivation of CaMKII because of elevated cytosolic [Ca2+]. We attribute the Ca2+ dyshomeostasis to delayed extrusion of cytosolic Ca2+ Suggesting that this defect in Ca2+ extrusion arose from an insufficient response to the bioenergetic demand of neural activity, depolarization-induced mitochondrial ATP production was diminished in vapbP58S neurons. These findings point to bioenergetic dysfunction as a potential cause for the synaptic defects in vapbP58S -expressing motor neurons.SIGNIFICANCE STATEMENT Whether the synchrony between the rates of ATP production and demand is lost in degenerating neurons remains poorly understood. We report that expression of a gene equivalent to an amyotrophic lateral sclerosis (ALS)-causing variant of vesicle-associated membrane protein B (VAPB) in fly neurons decouples mitochondrial ATP production from neuronal activity. Consequently, levels of ATP in mutant neurons are unable to keep up with the bioenergetic burden of neuronal activity. Reduced rate of Ca2+ extrusion, which could result from insufficient energy to power Ca2+ ATPases, results in the accumulation of residual Ca2+ in mutant neurons and leads to alterations in synaptic vesicle (SV) release and synapse development. These findings suggest that synaptic defects in a model of ALS arise from the loss of activity-induced ATP production.

ID: 38615685
Title: Toxic gain-of-function mechanisms in C9orf72 ALS-FTD neurons drive autophagy and lysosome dysfunction.
Abstract: Hexanucleotide repeat expansions in the C9orf72 gene are the primary genetic cause for both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two related neurodegenerative diseases. Significant advances in the elucidation of the disease mechanisms responsible for C9orf72 ALS-FTD have revealed both a toxic gain-of-function and a loss-of-function mechanism as possible underlying disease cause. As the differential contribution of both gain and loss of function in C9orf72 ALS-FTD pathogenesis remains debated, we investigated disease mechanisms in motor neurons derived from both authentic human patient C9orf72 ALS-FTD iPSCs as well as a C9orf72 knockout iPSC line. We found that patient neurons presented with less motile and enlarged lysosomes, a decrease in autophagic flux and an increase in SQSTM1/p62 puncta and insoluble TARDBP/TDP-43 species. Importantly, we found that C9orf72 knockout barely has any influence on these phenotypes and mainly results in impaired endosomal maturation. Together, our data suggest that toxic gain-of-function, rather than loss-of-function, mechanisms in C9orf72 ALS-FTD impair the autophagy-lysosome system in neurons.

ID: 38876108
Title: Cellular and axonal transport phenotypes due to the C9ORF72 HRE in iPSC motor and sensory neurons.
Abstract: Induced pluripotent stem cell (iPSC)-derived motor neurons (MNs) from patients with amyotrophic lateral sclerosis (ALS) and the C9ORF72 hexanucleotide repeat expansion (HRE) have multiple cellular phenotypes, but which of these accurately reflect the biology underlying the cell-specific vulnerability of ALS is uncertain. We therefore compared phenotypes due to the C9ORF72 HRE in MNs with sensory neurons (SNs), which are relatively spared in ALS. The iPSC models were able to partially reproduce the differential gene expression seen between adult SNs and MNs. We demonstrated that the typical hallmarks of C9ORF72-ALS, including RNA foci and dipeptide formation, as well as specific axonal transport defects, occurred equally in MNs and SNs, suggesting that these in vitro phenotypes are not sufficient to explain the cell-type selectivity of ALS in isolation.

ID: 41145518
Title: Intrinsically accelerated cellular degradation is amplified by TDP-43 loss in ALS-vulnerable motor neurons in a zebrafish model.
Abstract: Selective neuronal vulnerability is a defining feature of neurodegenerative disorders, exemplified by motor neuron degeneration in amyotrophic lateral sclerosis (ALS). The nature of motor neurons underlying this selectivity remains unresolved. Here, by monitoring autophagy at single-cell resolution across the translucent zebrafish spinal cord, we identify motor neurons as the cell population with the highest autophagic flux. Large spinal motor neurons (SMNs), most susceptible to ALS, exhibit higher flux compared to smaller SMNs and ALS-resistant ocular motor neurons. Notably, large SMNs accelerates both autophagy and proteasome-mediated degradation, which are further augmented by TDP-43 loss. Additionally, acceleration of multiple unfolded protein response pathways indicates their innate tendency to accumulate misfolded proteins. Enhanced cellular degradation in large SMNs is neuroprotective as its inhibition halts axon outgrowth. These findings propose that cell size-associated degradation load underlies selective neuronal vulnerability in ALS, highlighting the alleviation of catabolic stress as a target of therapy and prevention.

ID: 41476313
Title: MiR-124-3p inhibits stomach adenocarcinoma progression by targeting AHR to induce autophagy.
Abstract: MicroRNA-124-3p (miR-124-3p) has been widely reported as an important tumor-suppressive regulator in multiple malignancies. Nevertheless, its precise biological function in stomach adenocarcinoma (STAD) remains insufficiently clarified. We applied large-scale bioinformatics interrogation of The Cancer Genome Atlas (TCGA) STAD cohort, combined with in vitro cellular assays and in vivo xenograft experiments, to explore both the biological significance and molecular mechanisms of miR-124-3p in STAD progression. MiR-124-3p expression was significantly downregulated in STAD tissues and correlated with advanced pathological stage, poor prognosis, and reduced survival outcomes. Functional investigations confirmed that miR-124-3p directly interacts with the 3'-UTR of the aryl hydrocarbon receptor (AHR) mRNA, suppressing its expression and inducing autophagy. This regulation led to impaired proliferation, migration, and invasiveness of STAD cells. Restoration of AHR expression reversed these tumor-suppressive effects. Moreover, in vivo delivery of miR-124-3p inhibited tumor growth and mitigated cancer-induced cachexia in nude mice. These findings establish miR-124-3p as a key suppressor of STAD progression via AHR-mediated autophagy, underscoring its promise as both a diagnostic biomarker and a therapeutic candidate.

ID: 41638908
Title: TBK1 activity regulates the directionality of axonal transport of signalling endosomes.
Abstract: The polarised and complex morphology of neurons poses massive challenges for efficient cargo delivery between the axon and soma, a process termed axonal transport. We have previously shown that the retrograde axonal transport of pro-survival, neurotrophic signalling endosomes relies on Rab7 in motor neurons, and that their trafficking is impaired in the early stages of amyotrophic lateral sclerosis (ALS) pathogenesis. Here, we report the effect of Rab7 phosphorylation on the transport of these signalling endosomes. We show that the ALS-linked kinase TBK1 phosphorylates Rab7 at S72 in neurons, altering its binding to cytoplasmic dynein adaptors. Accordingly, both TBK1 knockdown and the expression of a loss-of-function Rab7 mutant (S72E) induce aberrant bidirectional movement of signalling endosomes without modifying neuronal polarity or endosomal sorting. This alteration is specific for signalling endosomes, as axonal transport of lysosomes and mitochondria remains unaffected. We have therefore discovered a new TBK1 function that ensures the unidirectional transport of signalling endosomes, suggesting that reduced TBK1 activity determines retrograde transport dysfunctions and long-range signalling impairments.

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.

ID: 41758656
Title: Delineating the interactions among mutual miRNAs and target genes associated with Parkinson's disease, endoplasmic reticulum stress and autophagy pathways: a computational analysis.
Abstract: MicroRNAs have been implicated in the pathophysiology of several diseases including Parkinson's disease (PD). Endoplasmic reticulum (ER) stress mediated unfolded protein response (UPR) pathway and autophagy play a vital role in preventing the accumulation of α-synuclein, which is one among the major causes of PD. This study presents data on the interactions among miRNAs and genes involved in PD, ER stress and autophagy pathways analysed using computational tools. When the interactions among selected 89 miRNAs and 44 genes were visualised using Cytoscape, three miRNAs- hsa-miR-34a-5p, hsa-miR-9-5p and hsa-miR-214-3p were selected as hub-miRNAs based on their degree of interaction. Further, functional annotation and functional interaction analyses were carried out for the target genes of these hub-miRNAs. Based on ontology and enrichment analyses data, the targets of miR-34a-5p and miR-9-5p such as BCL2, BECN1, ATG5, HMGB1, and ATG7 were observed to be involved in apoptosis and autophagy. Further, the functional interactions of ATG5-BECN1 and BECN1-HMGB1 emphasised their integrative roles in autophagy. On the other hand, the targets of miR-214-3b such as XBP1, ATF4, BCL2L11, and BAX were found to be associated with ER stress and apoptosis. Also, functional interactions observed between XBP1-ATF4, ATF4-BCL2L11, and BCL2L11-BAX highlighted their integrative roles in neuronal apoptosis and ER stress pathways. Overall findings indicated that dysfunctions of these miRNAs might contribute to neuronal apoptosis through their regulatory roles in autophagy and ER stress pathways.

ID: 41888437
Title: Preservation of miR-9-5p and miR-124-3p in ALS-resistant oculomotor neurons contrasts with their downregulation in vulnerable spinal motor neurons, irrespective of TDP-43 pathology.
Abstract: Selective vulnerability of motor neurons is a defining feature of amyotrophic lateral sclerosis (ALS) and provides a valuable framework for uncovering mechanisms that distinguish resilient from vulnerable neuronal populations. We investigated whether dysregulation of neuroprotective microRNAs (miRNAs), miR-9-5p and miR-124-3p, contributes to the differential susceptibility of motor neuron subtypes. We focused on cervical spinal motor neurons (SMNs), which undergo drastic degeneration in ALS, and oculomotor neurons (OMNs), which remain functionally intact and rarely degenerate, allowing preservation of eye movement in ALS patients. Using a modified multiplexed fluorescent in situ hybridization protocol combined with immunofluorescence, we quantified the expression of miR-9-5p and miR-124-3p in cervical SMNs and OMNs from ALS and control cases. We observed significant downregulation of both miRNAs in ALS SMNs, while their expression was maintained in ALS OMNs. Stratification of ALS SMNs by TDP-43 pathological status revealed similarly reduced miRNA expression in neurons with and without cytoplasmic inclusions, suggesting that miRNA downregulation occurs independently of visible TDP-43 pathology. We assessed the localization of the Dicer cofactor TRBP and found that it colocalized with TDP-43 inclusions in ALS SMNs, suggesting that TRBP sequestration could prevent proper miRNA processing. However, TRBP remained normally localized in neurons without cytoplasmic inclusions, indicating that sequestration cannot fully account for miRNA reduction across all ALS motor neurons. These findings support a model in which early or subtle disruptions, preceding visible pathology, may also contribute to miRNA downregulation in ALS. By identifying preserved miRNA networks as correlates of oculomotor neuron resilience in ALS, this work also exposes new therapeutic targets potentially capable of reinstating miRNA expression and reprogramming vulnerable SMNs.

ID: 41890274
Title: Excitotoxicity in amyotrophic lateral sclerosis: a key pathogenic mechanism.
Abstract: Amyotrophic lateral sclerosis is a complex neurodegenerative disease affecting motor neurons, characterized by the involvement of various factors, including oxidative stress, inflammatory processes, glutamate excitotoxicity, mitochondrial dysfunction, protein aggregation, axonal transport abnormalities, and apoptosis. The complexity of amyotrophic lateral sclerosis arises from its multifactorial aetiology involving diverse genetic, protein, metabolic, and cellular alterations. Mutations of different genes, such as SOD1, C9ORF72, TARDBP, and FUS, have been identified as critical contributors to disease pathophysiology through their facilitation of aberrant protein misfolding and aggregation. All these factors disrupt glutamate homeostasis, leading to calcium-mediated neurotoxicity. Under oxidative stress, motor neurons exhibit a diminished capacity to regulate calcium influx, along with impaired functioning of the mitochondria and endoplasmic reticulum, further compromising cellular integrity. Dysregulation of glutamate signalling also triggers astrocytic stress responses, leading to reduced glutamate clearance, thus worsening neuronal damage through excitotoxic mechanisms. These factors contribute to the excessive production of reactive oxygen species, which exacerbates glutamate imbalance and establishes a detrimental cycle of neuronal damage and glial dysfunction, ultimately intensifying excitotoxicity. This review aims to highlight the role of excitotoxicity in motor neuronal degeneration and to explore the molecular mechanisms underlying the pathogenesis of amyotrophic lateral sclerosis. It also examines current therapeutic approaches, including approved treatments and ongoing clinical trials to reduce excitotoxicity, while emphasizing the urgent need for novel, targeted strategies. Given the lack of definitive diagnostic tools and curative therapies, advancing our understanding of the molecular mechanisms driving excitotoxicity and neurodegeneration is, therefore, crucial for the development of more effective, disease-modifying treatments to slow amyotrophic lateral sclerosis progression.

ID: 41890591
Title: Axonal transport impairment as an upstream mechanism in amyotrophic lateral sclerosis pathogenesis.
Abstract: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive loss of upper and lower motor neurons. Despite marked genetic and pathological heterogeneity, a unifying pathogenic framework remains lacking. We propose that axonal transport impairment represents an early and convergent but genotype-modulated upstream vulnerability in ALS, contributing to distal synaptic failure, bioenergetic stress, protein aggregation, neuroinflammation, and neuronal death. Across many ALS models, including SOD1, TARDBP (TDP-43), FUS, and C9orf72, transport deficits are frequently detectable in presymptomatic stages, often preceding overt motor neuron loss or clinical manifestation, although temporal ordering varies by molecular subtype. Human data from induced pluripotent stem cell-derived motor neurons and neuroimaging in mutation carriers further support early transport dysfunction in both familial and sporadic ALS. We synthesize genetic, cellular, and systems-level evidence demonstrating that diverse ALS-associated mutations converge on intracellular trafficking machinery through distinct but interacting mechanisms, disrupting long-range cargo delivery and clearance in motor neurons. This framework provides a mechanistic basis for selective motor neuron vulnerability, the dying-back pattern of neuromuscular junction degeneration, and the emergence of downstream pathological hallmarks including mitochondrial dysfunction, excitotoxicity, aggregation, and inflammation. This model generates testable predictions regarding presymptomatic transport biomarkers and the timing of therapeutic intervention. We discuss implications for biomarker development and therapeutic strategy, proposing restoration of axonal transport as a central component of rational multimodal disease modification in ALS.

ID: 41951265
Title: Disappearing corticospinal tract on routine MRI: dynamic signal evolution in primary lateral sclerosis.
Abstract: Primary lateral sclerosis (PLS) may show corticospinal tract (CST) hyperintensity on fluid-attenuated inversion recovery and motor cortex hypointensity on susceptibility-weighted imaging (SWI); however, its longitudinal evolution remains poorly understood. Here, we describe two cases with definite PLS, who were followed up for 15 and 6 years and assessed using qualitative visual magnetic resonance imaging (MRI) scores. Both patients initially exhibited CST hyperintensity. Despite progressive clinical deterioration due to wheelchair/walker dependence, serial MRI demonstrated complete CST normalisation (score 0/16). Concurrently, SWI revealed progressive motor cortex hypointensity, consistent with iron deposition. These cases illustrate a possible dissociation between conventional and susceptibility-based MRI markers, suggesting dynamic pathophysiological processes and potentially early inflammation followed by gliotic remodelling, although technical factors cannot be excluded. A normal-appearing CST should not exclude advanced PLS, and progressive motor cortex hypointensity may provide a more stable marker. Prospective studies with standardised protocols are required to validate these observations.

ID: 42096556
Title: Short RNA chaperones promote aggregation-resistant TDP-43 conformers to mitigate neurodegeneration.
Abstract: Aberrant aggregation of the prion-like RNA binding protein TDP-43 drives several fatal neurodegenerative proteinopathies, including amyotrophic lateral sclerosis (ALS). In this work, we define how short, specific RNAs solubilize TDP-43. These short RNAs engage and stabilize the TDP-43 RNA recognition motifs, which allosterically destabilizes a conserved helical region in the prion-like domain, thereby promoting aggregation-resistant conformers. Sequence-space mining identified short RNA chaperones with enhanced activity against TDP-43 and disease-linked variants. Enhanced short RNA chaperones mitigated aberrant TDP-43 phenotypes in optogenetic models and in ALS patient-derived and control motor neurons. In mice with cytoplasmic TDP-43 aggregation and motor neuron loss, an enhanced short RNA chaperone reduced pathological aggregation, restored TDP-43 function, and conferred neuroprotection. These results define a mechanistic and therapeutic framework for RNA-based strategies to counter TDP-43 proteinopathies.

ID: 42104730
Title: A novel synaptic compartmentalization failure framework for neurodegeneration.
Abstract: Synaptic plasticity relies on precise spatial and temporal compartmentalization of signaling within dendritic spines, presynaptic terminals, and axonal domains. This compartmentalization is usually reinforced through activity-dependent remodeling of spine geometry, cytoskeletal scaffolds, calcium handling, and local protein synthesis, allowing plasticity signals to remain localized and terminate appropriately. Here, a unifying framework is proposed in which neurodegenerative diseases emerge when the capacity to maintain and renew these compartments declines. Ageing and glial dysregulation may act as major biological drivers of this process by altering dendritic spine structure, calcium homeostasis, metabolic support, neurotransmitter clearance, and activity-dependent synaptic remodeling. In this state, plasticity induction remains largely preserved, but signaling becomes spatially diffuse and temporally prolonged, imposing chronic structural and energetic stress on synapses and axons. Proteins such as tau and alpha synuclein, which normally support cytoskeletal organization and dynamic phase separated assemblies, may become destabilized under these conditions leading to pathological aggregation. This framework provides an explanation for early synaptic dysfunction, selective neuronal vulnerability, long presymptomatic phases, network-level disease propagation, the protective effects of education and cognitive engagement, and the limited efficacy of proteinopathy centric therapeutic strategies. Neurodegeneration may be conceptualized as a failure of synaptic compartmentalization, with protein aggregation arising downstream of this primary vulnerability.

ID: 42141072
Title: Axonal dying back of upper motor neurons in human ALS.
Abstract: Patients with amyotrophic lateral sclerosis (ALS) typically present with arm, leg, or bulbar weakness. While genetics plays a clear role, it cannot explain why symptoms start focally or how upper (UMN) and lower motor neuron (LMN) systems are linked. In this clinicopathological case series, we examined the relationships between UMN/LMN disease in ten ALS patients. Detailed clinical assessments and motor cortex, brainstem, and spinal cord tissues were collected via rapid autopsy. Tissues were stained for UMN/LMN, myelin, axons, microglia, and pTDP43, and RNA-sequencing was performed. None of the patients had symptoms of frontotemporal dementia (FTD), but all had focal sites of clinical onset and both UMN/LMN involvement. LMN degeneration and microglial activation were highest at disease onset sites. UMN degeneration was present at all spinal cord levels through the medulla, regardless of onset site. Surprisingly, there was no evidence of UMN axonal degeneration above the brainstem. While extensive pTDP43 aggregates were seen in degenerating LMNs, no pTDP43 aggregates were seen in UMN cell bodies or their axons. RNA-sequencing implicated inflammatory pathways at sites of disease onset. Our findings suggest that some ALS patients without FTD have a dying back of UMN axons rather than a primary upper neuronopathy of neurons.

ID: 42186501
Title: SOD1 amyotrophic lateral sclerosis associated with Neurosarcoidosis: a case report and review of the literature.
Abstract: We describe a 37-year-old man with coexisting amyotrophic lateral sclerosis (ALS) caused by a mutation in superoxide dismutase 1 (SOD1) and probable neurosarcoid myeloradiculitis. The concurrence of the two rare conditions posed significant diagnostic and therapeutic challenges. We discuss the diagnostic timeline, therapeutic interventions, outcomes over half a decade of care, and a review of relevant literature.

ID: 42204279
Title: Evaluation of triumeq treatment on a TDP-43 mouse model of amyotrophic Lateral sclerosis.
Abstract: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterised by the accumulation of TAR DNA Binding Protein (43 kDa; TDP-43) within the cytoplasm of neurons. Endogenous retroviruses (ERVs) have been implicated in ALS pathology and the application of antiretroviral therapy, specifically Triumeq, has been proposed for treatment of ALS. However, evidence to support the actions of Triumeq in ALS is lacking. This study investigates the effects of the antiretroviral treatment Triumeq on ALS disease that occurs through TDP-43 pathology by utilising the doxycycline (Dox)-suppressible rNLS8 TDP-43 expression mouse model. In this model, TDP-43 accumulation in the cytoplasm is induced after removal of Dox. Disease was assessed through measures of body weight, neurological score, motor function, urinary p75ECD and inflammatory marker expression. Mice were treated with Triumeq and TDP-43 pathology and inflammatory marker expression examined. Triumeq treatment significantly improved motor function early on in the disease course but did not impact other disease progression markers or disease endpoint. In this TDP-43 ALS mouse model, there was a positive association of TDP-43 mRNA levels with transcription factor ATF4, and inflammatory markers CXCL10 and IRF-1, and Triumeq treatment negated this association. Triumeq treatment transiently and modestly improved motor function and influenced TDP-43 associated inflammatory gene expression in an ALS mouse model. These findings support the potential use of Triumeq in treating TDP-43-associated ALS and supports further investigation to better understand if the beneficial actions of Triumeq are via disruption of TDP-43-driven inflammation in ALS.

ID: 42210413
Title: VAPB confers selective neuroprotection by driving autophagic degradation of pathogenic aggregates in ALS.
Abstract: During the progression of amyotrophic lateral sclerosis (ALS), only specific motor neurons (MNs) preferentially deteriorate, while others are spared until the disease reaches its end stage. Resilient MNs possess several protective factors, yet the precise molecular mechanism(s) underlying selective neuronal vulnerability remains poorly understood. Vesicle-associated membrane protein (VAMP)-binding protein B (VAPB) is an endoplasmic reticulum (ER) protein involved in protein quality control (PQC) mechanisms, including unfolded protein response (UPR) as well as autophagy. A dominantly inherited P56S mutation in the VAPB gene has been linked to ALS8, atypical ALS, and late-onset spinal muscular atrophy (SMA). The P56S VAPB mutation causes ER-associated inclusions, disorganization, and ER stress, contributing to MN degeneration through toxic gain and loss of function. Over-expression of VAPB protein confers neuroprotection in a mouse model of ALS, and increased levels of neuronal VAPB inversely correlate with the absence of pathological aggregates. We hypothesize that VAPB is crucial for motor neuron survival by promoting autophagic degradation of ALS-associated aggregates, while lack of VAPB confers neuronal vulnerability. We analyzed the brain and spinal cord from sporadic (s) and familial (f) ALS patients, comparing patterns of VAPB immunoreactivity using immunohistochemistry, complemented by Western and dot blot analysis. Pathophysiological insights from these studies were further explored using cell culture models, including MNs derived from induced pluripotent stem cells (iPSCs). Consistent with our hypothesis we observed that MNs/neurons resistant to ALS exhibited elevated levels of VAPB and were devoid of pathogenic aggregates. Similarly, ALS-resistant oculomotor neurons showed increased VAPB immunoreactivity compared to normal controls. VAPB was often found to be sequestered within toxic aggregates alongside autophagy-related proteins in the lumbar spinal cord MNs. Notably, a compensatory increase in VAPB immunoreactivity was observed at the C-bouton synapse, suggesting a potential alternative mechanism of neuroprotection. Supporting these findings, in vitro experiments indicated that VAPB overexpression promoted autophagy and assisted in clearing ALS-associated RNA-binding protein aggregates. In summary, VAPB promotes selective neuronal survival by facilitating the autophagic clearance of toxic aggregates. Abnormal VAPB accumulations likely disrupt these neuroprotective processes.

ID: 42213237
Title: Reevaluating the role of beta2-microglobulin: new insights on selective vulnerability in ALS pathology.
Abstract: Amyotrophic lateral sclerosis (ALS) is characterized by the selective loss of motor neurons (MNs). Why these neurons are particularly vulnerable in ALS remains unclear, as does why certain MN groups remain resistant throughout the disease course. We investigated the role of the human leukocyte antigens (HLAs) and beta2-microglobulin (β2m) in MN susceptibility to ALS, given their reported involvement in both prolonging and shortening disease progression. Loss of HLAs in ALS has also been shown to increase MNs vulnerability to toxicity exerted by activated astrocytes. RNA sequencing of control tissues demonstrated that disease-resistant oculomotor neurons (OMNs) and Onuf's MNs exhibited β2m and HLA mRNA levels comparable to those of vulnerable spinal MNs, suggesting that baseline differences in these transcripts do not explain the differential vulnerabilities of these MN groups. However, HLA protein levels showed an inverse correlation with spinal MN size, with the large MNs, those lost early in ALS, displaying the lowest HLA expression. HLA protein levels were also reduced in spinal MNs from end-stage ALS patient tissues, while remaining relatively unchanged in OMNs. In contrast, spinal MNs uniquely exhibited significant upregulation of β2m and HLA-C transcripts during disease, likely reflecting a protective compensatory response. Together, these findings suggest that β2m and HLAs may contribute to spinal MN vulnerability in ALS. To assess their functional role, β2m knockout mice were crossbred with SOD1G93A ALS mice. Loss of β2m did not alter life span of the ALS mice, but led to partial preservation of lumbrical muscle innervation that was insufficient to maintain motor function. Analysis of GFAP immunoreactivity revealed marked neuroinflammation activation in the spinal cords of β2m knockout mice. As these mice retain normal MN numbers and life-span, this indicates that loss of functional MHC-I, even in the presence of astrocyte activation, is insufficient to cause MN disease. Furthermore, β2m knockout significantly increased GFAP activation in SOD1G93A mice, but did not further exacerbate disease progression, suggesting that loss of functional MHC-I does not necessarily render MNs more vulnerable to astrocyte toxicity. Overall, these findings indicate that β2m and HLAs are dynamically regulated in ALS, and may influence MN vulnerability, but they are not major disease modifiers in ALS.

ID: 42215790
Title: The C9orf72/SMCR8 complex maintains microglial homeostasis via RAB8A-ESCRT-mediated lysosomal repair.
Abstract: Microglia are critical regulators of neuroinflammation and neurodegeneration. Haploinsufficiency of C9orf72, the most frequently mutated gene in amyotrophic lateral sclerosis and frontotemporal dementia, has been linked to autophagy-lysosomal pathway defects, but the role of C9orf72 in microglia remains unclear. Here, we identify the C9orf72/SMCR8 complex as a key regulator of microglial homeostasis through promoting lysosomal membrane repair. Loss of C9orf72 and SMCR8 in mice causes age‑dependent neuroinflammation and microgliosis, with microglia adopting a disease-associated state. In aged brain and spinal cord tissue, microglia display lysosomal damage marked by galectin‑3 accumulation. Using a lysosomotropic agent to induce lysosomal damage in microglia, we find that C9orf72/SMCR8-deficient cells accumulate damaged lysosomes and show defective recruitment of phosphorylated RAB8A and the Endosomal Sorting Complexes Required for Transport (ESCRT) machinery to damaged lysosomes. Notably, mutant microglia accumulate GTP‑bound RAB8A, which becomes hyperphosphorylated and mislocalized to RAB7-positive, LAMP1-negative vesicles. The GTPase-activating activity of the C9orf72/SMCR8 complex is essential for lysosomal repair. Our findings reveal that the C9orf72/SMCR8 complex coordinates RAB8A-ESCRT-mediated lysosomal repair to safeguard microglial homeostasis and limit neuroinflammation.

ID: 42224592
Title: miR-146a is a pleiotropic regulator of motor neuron degeneration.
Abstract: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting motor neurons. Here, we have profiled motor neuron microRNAs (miRNAs) during motor neuron degeneration in vivo to gain a better understanding of ALS pathophysiology. We demonstrate that one miRNA, miR-146a, is downregulated in diseased motor neurons despite upregulation in bulk tissue. Genetic deletion of miR-146a significantly extended survival in SOD1G93A mice with heterozygous animals demonstrating the largest benefit. A corresponding reduction in spinal cord gliosis but not motor neuron loss was observed. Finally, we observed that a proportion of miR-146a knockout animals develop spontaneous paralysis, motor neuron loss and chronic neuroinflammation with advanced age. Together these findings demonstrate that a single miRNA influences multiple aspects of motor neuron disease and highlights the complex role for neuroinflammation in ALS pathogenesis.

ID: 42258722
Title: Targeting the cGAS-STING pathway mitigates Huntington disease pathogenesis in a knock-in mouse model.
Abstract: Cyclic GMP-AMP synthase (cGAS) and its downstream effector, stimulator of interferon genes (STING), form a key cytosolic DNA-sensing pathway that drives innate immune activation and proinflammatory signaling. We previously showed that cGAS is upregulated in Huntington disease (HD) cellular models, where it regulates autophagy and inflammation; however, its in vivo role remained unclear. Here, we genetically ablated cGAS in Q175DN knock-in HD mice and performed longitudinal behavioral assessments from 2 to 14 mo of age. cGAS deletion significantly improved HD-associated motor deficits, including rotarod performance and beam-walk coordination, and mitigated progressive body-weight loss. Histological analyses revealed reduced lateral ventricle enlargement and decreased striatal astrogliosis and microgliosis. While minimal effects were observed in wild-type littermates, transcriptomic profiling of HD brains lacking cGAS showed downregulation of genes involved in development and cell-cell communication, along with upregulation of genes linked to ion transport and synaptic function. Lipidomic analysis further demonstrated increased levels of immunoregulatory lipids, particularly 12-HETE and 12-HEPE, indicating a shift toward a protective lipid profile. Importantly, pharmacological inhibition of STING using H-151 improved age-dependent motor performance, reduced striatal atrophy, and attenuated glial cell activation in Q175DN mice. Collectively, these findings identify the cGAS-STING pathway as a critical driver of HD progression and support its inhibition as a promising therapeutic strategy.

ID: 42261159
Title: The Pivotal Role of HDAC6 in Amyotrophic Lateral Sclerosis: Neuroprotective Protagonist or Degenerative Adversary?
Abstract: The review specifically examines the pivotal role of HDAC6 in the pathophysiological pathway of Amyotrophic Lateral Sclerosis (ALS), an escalating neurodegenerative ailment marked by the discerning damage to motor neurons. Several lines of evidence implicate inadequate proteostasis in significantly influencing neuronal degeneration. The accumulation of misfolded proteins and proteotoxicity are highlighted as significant factors in ALS pathophysiology. Key pathological hallmarks include ubiquitin-positive inclusions, disrupted RNA metabolism, cytoskeletal perturbations, and compromised axonal transport systems. HDAC6 dysregulation disrupts axonal transport, impairing mitochondrial function and increasing oxidative stress, leading to rapid motor neuron damage and cell death. The enzyme's aberrant deacetylation of α-tubulin destabilizes microtubules and impairs intracellular trafficking. Despite HDAC6's participation in these unfavorable processes, it also exerts neuroprotective properties. It deacetylates tubulin, promoting efficient axonal transport and autophagic clearance. HDAC6 helps form aggresomes and stress granules, which are essential for cellular defence against proteotoxic stress. Through its zinc finger ubiquitin-binding domain, HDAC6 interacts with polyubiquitinated proteins, facilitating their autophagic degradation. HDAC6 inhibition can boost autophagic flux and reduce protein aggregation, while its activation may amplify the protective effects. This dichotomous behaviour of HDAC6 may pose an obstacle to the design of targeted therapy. Illuminating the complex mechanisms through which HDAC6 influences neurodegeneration and neuroprotection is important before constructing effective treatments for ALS. The review provides a clear understanding of the complex role of HDAC6 in ALS pathogenesis and highlights potential strategies to improve the prognosis of people affected by this neurological illness.

ID: 42262134
Title: Alpha-synuclein at the crossroads of host-virus interactions: immunological roles beyond the nervous system.
Abstract: Alpha-synuclein (α-syn) is best known as a presynaptic protein that supports synaptic vesicle dynamics and neurotransmission. Conversely, misfolded or aggregated α-syn represents a hallmark of synucleinopathies, including Parkinson's disease. Beyond the nervous system, α-syn has been detected in peripheral compartments, including blood cells and selected epithelial tissues, although the robustness and context dependence of expression outside neuronal and erythroid lineages remain under active investigation. Also, it can be released extracellularly through unconventional secretion or cell damage. These observations have reframed α-syn as an immune-relevant molecule positioned at host-pathogen interfaces, endowed with antimicrobial peptide-like and damage-associated molecular pattern-like properties that enable shaping of both innate and adaptive immunity. Increasing evidence indicates that viral challenge alters α-syn expression, localization, and conformational states in central and peripheral settings, in part through interferon-dependent programs that couple antiviral immunity with cellular homeostasis. A plethora of RNA viruses, such as influenza virus, flavivirus, enterovirus, and coronavirus, perturb α-syn abundance, post-translational modifications, trafficking, secretion, and aggregation propensity. These effects converge on shared mechanisms that include altered proteostasis, autophagy-lysosomal dysfunction, oxidative and mitochondrial injury, and inflammatory signaling. Importantly, outcomes are highly context dependent, ranging from cell-intrinsic antiviral restriction to aggregation-prone states that may fuel chronic inflammation and neurodegeneration. Collectively, the evidence discussed herein supports a dual framework in which α-syn contributes to antiviral defense; yet, under conditions of sustained inflammation or impaired clearance, it may undergo pathological transformation that promotes neuronal damage. Defining when virus-induced α-syn responses are protective versus pathogenic, and clarifying their relevance to human disease, will be critical for developing strategies that target host-virus interactions, neuroinflammation, and α-syn proteostasis in infection-associated synucleinopathies.

ID: 42281996
Title: Single-nucleus multiomic atlas of ALS primary motor cortex nominates neuroprotective WDR49-expressing astrocytes.
Abstract: Amyotrophic lateral sclerosis (ALS) causes selective neurodegeneration in primary motor cortex, yet cell-type-specific molecular changes driving this vulnerability remain poorly understood. We present an integrated single-nucleus RNA- and ATAC-sequencing atlas of 778,330 nuclei from the primary motor cortex of 140 genetically characterised donors. ALS is associated with widespread transcriptional reprogramming driven by a common set of transcription factors (TFs) across multiple cell-types. Astrocytes harbour the most differentially expressed genes. Within astrocytes, a WDR49-expressing subpopulation is spatially associated with TDP-43 pathology, and genetic variants within WDR49 confer risk for both sporadic and monogenic autosomal dominant ALS. In patient-derived induced astrocytes, WDR49 protein abundance predicts the survival of co-cultured neurons. WDR49 localises to PML nuclear bodies, where it regulates astrocyte reactivity and secretion of EVs containing protein chaperones. Together, these in vivo and in vitro findings suggest that WDR49+ astrocytes mount a compensatory secretory response to extracellular protein aggregates, and that loss of this capacity lowers the threshold for ALS pathogenesis.

ID: 42300093
Title: Reduced Mechanical Tactile Stimulation Under Space Microgravity Affects Synaptic Signaling and Contributes to Neuromuscular Aging in Caenorhabditis elegans.
Abstract: Although space travel is becoming more accessible, our understanding of how the space environment and microgravity (μG) affect biology, physiology, and human health remains incomplete. This study examined the effects of μG on synaptic signaling and neuromuscular aging in Caenorhabditis elegans. The D01 cohort, consisting of L4 larvae to young adults raised in μG, exhibited a downregulation of genes linked to synaptic signaling, dopamine response, locomotion, cuticle development, and mitochondrial metabolism. This was accompanied by altered synapse dynamics, reduced motility, and shorter body length. In μG, aged worms showed a reduction in collagen gene expression, increased abnormalities in motor neuron morphology, changes in synaptic vesicle dynamics, and a collapse of mitochondrial morphology in body wall muscles, highlighting exacerbated aging-like phenotypes. The gentle-touch mechanoreceptor MEC-4 was identified as a key mediator of μG-induced body length reduction and changes in extracellular matrix gene expression. mec-4 mutants did not show μG-associated body shortening. The expression of most mechanoreceptor genes, including stretch-activated channels unc-105 and del-1, was downregulated under μG conditions. Notably, the expression of tmc-1 and degt-1 mechanoreceptor genes was downregulated independently of MEC-4. Restoration of physical stimulation using culture medium with small beads in space mitigated many μG-induced neuromuscular defects and expression alterations including those in mechanoreceptor genes. These results highlight the role of mechanical stimuli in maintaining neuromuscular integrity during spaceflight and suggest that restoring tactile input could counter health risks from reduced tactile stimulation during long-term space missions.

ID: 42346080
Title: Multimodal Proteomics Reveals Dysregulated Secretion and ECM Remodelling in Schizophrenia Patient iPSC-Derived Astrocytes.
Abstract: Astrocytes are increasingly implicated in the pathophysiology of schizophrenia (SCZ), yet how astrocytic dysfunction contributes to disease-relevant neuronal abnormalities remains unclear. Here, we used mass spectrometry-based proteomics to profile lysates (proteome) and secreted proteins (secretome) from iPSC-derived astrocytes originating from 9 SCZ patients and 8 healthy controls. Compartment-specific analyses showed that lysates were enriched for mitochondrial and nuclear pathways, whereas astrocyte-conditioned media (ACM) were enriched for extracellular matrix (ECM) and vesicle-associated proteins. Differential expression analysis revealed minimal overlap between dysregulated proteins in lysates and ACM, suggesting modality-specific effects of SCZ-associated donor background. Interestingly, ECM proteins and key secreted cues involved in synaptic development, including MFGE8 and SEMA3C, were selectively reduced in SCZ ACM, whereas RNA-processing proteins were aberrantly increased. This is in line with previously reported microRNA enrichment in extracellular vesicles (EV) derived from SCZ patients. Gene set analyses further identified the alteration in secretion and nuclear processes as well as the potential involvement of autophagy-dependent release mechanism in SCZ astrocytes. Together, these findings suggest disrupted astrocytic protein homeostasis and extracellular signalling in SCZ iPSC-derived astrocytes, providing mechanistic insight into astrocyte-mediated contributions to synaptic and circuit deficits in the disorder.

ID: 42356373
Title: Curcumin, Coenzyme-Q10, and Bioactive Compounds in Ashwagandha Extract: Multi-Targeting Potential of Co-Administered Natural Health Compounds as Therapeutic and Preventative Interventions in Alzheimer's and Parkinson's Disease Models.
Abstract: Neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD) represent a growing public health concern. Both disorders are driven by mitochondrial dysfunction, oxidative stress, impaired autophagy, neuroinflammation, and neuronal loss. Single-target therapeutics have failed to halt disease progression, highlighting the need for multi-target interventions that address the complex and interconnected nature of neurodegeneration. Natural health products (NHPs) such as curcumin (CUR), coenzyme-Q10 (CoQ10), and Ashwagandha (ASH) possess antioxidant, anti-inflammatory, neuroprotective, and neurotrophic properties that may collectively address this complex pathology. However, poor bioavailability and hydrophobicity have limited clinical translations. Novel formulations, including nanomicellar Ubisol-Q10 (UQ) and water-solubilized ASH (PTS-ASH), have demonstrated enhanced metabolic uptake and neuroprotective efficacy in preclinical models. Moreover, co-administered NHPs, such as CUR + CoQ10 and CoQ10 + ASH, may provide further benefits by diversified targeting of disease pathways. This review presents an integrative interpretation of a combined UQ + ASH "tonic" in transgenic AD and paraquat-induced PD animal models using previously published qualitative immunohistochemical and functional results. This report constructs a proposed mechanistic model illustrating how these compounds may interact across multiple stages of disease AD and PD progression. Based on comprehensive interpretation of the previous published reports, consistent trends suggest UQ stabilizes mitochondrial energetics and suppresses oxidative damage upstream, whereas ASH promotes downstream repair and synaptic modulation. Combined administration remained as providing balanced neuroprotective and functional outcomes. These interpretations of published reports and proposed mechanistic models aim to improve the translation and support the therapeutic potential of multi-component natural interventions for neurodegenerative diseases and highlight the importance of bioavailability-enhancing formulations in future preclinical and clinical research.

ID: 42358231
Title: Spermidine in Alzheimer's Disease: Evidence from Animal Models and Human Studies.
Abstract: Spermidine is a naturally occurring polyamine involved in multiple cellular processes, including growth regulation, protein translation, and autophagy. Increasing attention has been devoted to its potential neuroprotective effects, particularly in Alzheimer's disease (AD), a neurodegenerative disorder characterized by β-amyloid and phosphorylated tau accumulation, synaptic dysfunction, and progressive neuronal loss. In this narrative review, we examine potential mechanisms through which spermidine may influence AD pathophysiology and summarize available preclinical and clinical evidence. Preclinical studies indicate that spermidine induces autophagy, a key cellular clearance pathway responsible for removing damaged organelles and aggregated proteins. Because impaired neuronal autophagy contributes to the accumulation of β-amyloid and tau in AD, increasing intracellular spermidine levels may enhance the degradation of these toxic species. In addition, spermidine exhibits anti-inflammatory and antioxidant properties, attenuates microglial activation, and supports mitochondrial function. In animal models of AD and brain aging, spermidine administration has been associated with improvements in cognitive performance and synaptic function. However, human clinical evidence remains limited and largely inconclusive. Observational studies suggest associations between higher dietary spermidine intake and better cognitive outcomes, but do not establish causality. Randomized clinical trials to date are few, include small and heterogeneous populations, and have not demonstrated consistent effects on primary cognitive endpoints. Overall, spermidine represents a biologically plausible modulator of pathways relevant to neurodegeneration, but translation of preclinical findings into clinical benefit remains uncertain. Current evidence is insufficient to support its use as a therapeutic or preventive intervention in AD, and further well-designed clinical studies are required to clarify its efficacy and mechanisms of action. Alzheimer’s disease is one of the most common causes of memory loss in older adults. Researchers are searching for ways to protect brain cells and slow the biological processes that lead to this disease. One molecule that has recently attracted attention is spermidine, a natural compound found in all living cells and in many foods, including whole grains, legumes, mushrooms, and aged cheeses. Spermidine plays several roles in the body. One of its most important effects is activation of autophagy, a natural cellular process that removes damaged proteins and other cellular waste. This process is relevant to Alzheimer’s disease because the condition is associated with the accumulation of abnormal proteins in the brain. Experimental studies also suggest that spermidine may influence inflammation in the brain, support mitochondrial function (the energy system of cells), and help maintain communication between nerve cells. In this review, we summarized evidence from laboratory experiments, animal studies, and available human research. In animal models of brain aging and Alzheimer’s disease, spermidine consistently shows neuroprotective effects and can improve memory performance. Human evidence is more limited. Observational studies suggest that higher dietary spermidine intake may be associated with better cognitive performance, while clinical trials investigating supplementation have produced mixed results. Spermidine is naturally present in many foods and is increasingly studied in the context of aging and brain health. Overall, current evidence suggests that spermidine may play a role in brain aging. Larger and well-designed clinical studies are needed to clarify its potential relevance for Alzheimer’s disease.

ID: 42358353
Title: Inhibition of pathogenic tau signaling via blocking of the phosphatase-activating domain by novel small molecules.
Abstract: Tau pathology is a major feature of Alzheimer's disease (AD) and multiple other adult-onset neurodegenerative diseases. Aberrant exposure of an N-terminal phosphatase-activating domain (PAD) is characteristic of pathological tau, representing a toxic gain of function. Exposure of the PAD in pathological tau leads to dysregulation of protein phosphatase 1/glycogen synthase kinase 3 (PP1/ GSK3β) signaling, inhibition of fast axonal transport, synaptic dysfunction, and altered transcription, along with other pathological consequences. Previous studies showed that TNT1, an antibody against the PAD, blocked toxicity of pathogenic forms of tau. In this article, we describe a high-throughput screen for small molecules that block TNT1 binding to the PAD in an AlphaLISA screen and bind specifically to the PAD in surface plasmon resonance assays. Candidate PAD ligands (PADis) were identified, and initial biochemical and biophysical optimization produced PADis with increased affinity and selectivity. Three candidate PADis were evaluated in neuronal (rat E18 embryonic cortical neurons) and non-neuronal cells (HEK293T human embryonic kidney cells) using a nano-bioluminescence resonance energy transfer (nanoBRET) assay to assess PP1 binding and cell toxicity. All three compounds prevented PP1 binding to PAD and neurite degeneration due to pathological tau in primary cultured cortical neurons. The final candidates had an IC50 value between 10 and 20 nM in neurons with low cytotoxicity, CC50 > 75 μM in primary cultured neurons, and 40-100 μM in non-neuronal cells. PADi treatment of primary cultured neurons transfected with pathogenic tau restored axonal growth and prevented neurodegeneration. These studies establish a novel approach to therapeutics for Alzheimer's disease and tauopathies.

ID: 42359357
Title: Innate immune crosstalk in ALS/FTD pathogenesis.
Abstract: Marked by protein aggregation, impaired proteostasis, organelle stress, and chronic neuroinflammation, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) form a clinically, genetically, and pathologically overlapping disease spectrum. Increasing evidence indicates that innate immune activation is not merely a secondary response to neuronal injury, but an active driver of disease progression. In this review, we elaborate on how ALS/FTD-associated genetic lesions and pathogenic protein aggregates, including TDP-43, SOD1, FUS, and C9orf72-derived dipeptide repeat proteins, engage three interconnected innate immune pathways: cGAS-STING, NLRP3 inflammasomes, and TREM2-DAP12 signaling. We further highlight emerging crosstalk among these pathways, in which cGAS-STING and NLRP3 reinforce inflammatory signaling, while NLRP3-driven TREM2 shedding may impair microglial clearance and perpetuate proteostatic failure. Understanding this immune network may help define disease subtypes, identify biomarkers, and guide combinatorial therapeutic strategies that suppress harmful inflammation while preserving protective microglial functions.

ID: 42373582
Title: Unravelling the Significance of Cystatin C and Bunina Bodies in Amyotrophic Lateral Sclerosis Pathogenesis.
Abstract: Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND), is a fatal neurodegenerative disease primarily affecting motor neurons. Two key protein inclusions found in lower motor neurons serve as neuropathological hallmarks of the disease in human tissue: the TDP43-positive inclusion and the cystatin C-positive Bunina body. Despite their diagnostic specificity and presence in most sporadic and familial ALS cases, Bunina bodies remain poorly understood, and their true prevalence is likely underestimated. The co-occurrence of the Bunina body and the TDP43 inclusion may provide valuable insights into the development of TDP43 pathology in ALS. Thorough characterisation of the Bunina body is needed to understand this interplay and the broader pathomechanisms of disease. This review examines our current knowledge of Bunina bodies and the biochemical properties of cystatin C that may promote its aggregation. Sequestration and aggregation of cystatin C into Bunina bodies may diminish its neuroprotective functions, including cysteine protease inhibition, autophagy induction and anti-amyloidogenic activity, thereby contributing to ALS pathogenesis. This review also evaluates findings from human post-mortem tissue and ALS disease models, discussing the value and limitations of these models in the context of Bunina bodies and TDP43 pathology. Finally, we discuss cystatin C's use as a biomarker and its therapeutic potential. A deeper understanding of cystatin C biology, its relationship with TDP43 pathology and improved ALS models will be essential for determining whether targeting cystatin C could provide a viable avenue for future ALS therapies.

ID: 42384233
Title: Genome-wide spectrum of coding DNA variations in Indian patients with amyotrophic lateral sclerosis.
Abstract: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease with limited therapies, emphasizing the need for deeper understanding of disease pathogenesis. While more than 40 ALS-associated genes have been identified, their contribution varies significantly across populations and the data from the Indian population remains scarce. We aimed to comprehensively characterize the spectrum of coding DNA variations in ALS-associated genes and identify novel genetic contributors in an Indian cohort. Whole-exome sequencing on 761 ALS patients and 917 in-house healthy controls and repeat-primed PCR for expansions (C9orf72, ATXN2, NOTCH2NLC, NOP56) were performed. Variants were classified using ACMG guidelines, and rare variant association testing was conducted. Overall diagnostic yield was 15.90%, with pathogenic/likely pathogenic variants. Familial ALS showed higher diagnostic yield (36.95%) than sporadic ALS (12.96%). SOD1 dominated familial cases (53.85%), while OPTN, SOD1 and FIG4 were prevalent in sporadic cases. Homozygous SOD1 variants in six patients correlated with juvenile/young onset (< 30 years). C9orf72 expansions (4%) and ATXN2 repeats (1.7%) were identified at frequencies comparable with Asian cohorts. Rare variant analysis identified JAK2 as a novel genome-wide significant signal (FDR = 3.5 × 10-5). This first large-scale genomic survey of Indian ALS patients showed SOD1 being the predominant cause of fALS, while OPTN, FIG4, and other genes drive disease amidst low C9orf72 frequency. The novel JAK2 association suggests a potential neuroinflammatory mechanism, highlighting the importance of studying diverse populations to uncover distinct genetic etiologies.

ID: 42396948
Title: Dual-Modal Phototherapeutic Nanoagents Eradicating Drug-Resistant Bacteria via Multi-Pathway of Membrane Disruption, Oxidative Damage, and Energy Metabolism Interference.
Abstract: Faced with the growing challenge of antimicrobial resistance, developing non-antibiotic therapies is imperative. Photodynamic and photothermal therapy (PDT/PTT) are promising due to their minimal side effects and low risk of resistance. However, their efficacy is limited by inadequate reactive oxygen species (ROS) generation, finite photothermal conversion efficiency (PCE), bacterial antioxidant systems, biofilm barriers, and the constraints of single-modality treatments. To overcome these bottlenecks, this study innovatively co-assembled the phototherapeutic molecule Y6 with allicin (A) into the Y6A nanoplatform to achieve multi-mechanism antibacterial activity. Leveraging Y6's strong intramolecular charge transfer (ICT), extended π-conjugated backbone, and twisted long alkyl chain, Y6A simultaneously achieves efficient ROS generation and 55.2% PCE. Thus, Y6A eradicated up to 99.9% of Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa). This high efficacy is attributed to a synergistic antimicrobial strategy that couples structural disruption and oxidative damage via bimodal phototherapy with allicin-mediated suppression of biofilm formation and energy metabolism. In an MRSA-infected wound model, irradiated Y6A accelerated healing by 90%, modulating inflammation and promoting collagen deposition. This work not only confirms the exceptional PDT/PTT efficacy of Y6A against drug-resistant bacteria but also provides innovative concepts and experimental evidence for the development of synergistic phototherapeutic antibacterial materials.

ID: 42397604
Title: Disulfidptosis and its molecular mechanisms in cancer: mechanisms, regulation, and therapeutic potential.
Abstract: Disulfidptosis is a novel form of programmed cell death. It is triggered by metabolic and redox imbalance. It is executed through the irreversible collapse of the actin cytoskeleton. Its core mechanism involves the 'SLC7A11-cystine-NADPH-actin axis'. This process selectively kills cancer cells while sparing normal cells. This provides a new direction for low-toxicity anticancer therapy. This review systematically summarizes the multi-layered molecular regulatory network governing disulfidptosis. It elucidates the underlying mechanisms through several lenses. These include metabolic reprogramming (glucose metabolism, pentose phosphate pathway, cystine uptake), redox homeostasis (reactive oxygen species (ROS), glutathione system, thioredoxin system), cytoskeletal dynamics, and key signaling pathways such as Keap1-Nrf2, AMPK, and p53. The review clarifies its dual role in tumors. Cancer cells exhibit specific susceptibility due to metabolic reprogramming. Cells resistant to apoptosis or ferroptosis show heightened vulnerability. This stems from a 'fragile redox equilibrium'. However, functional polarity reversal of core regulatory molecules and tumor heterogeneity can also impact therapeutic efficacy. Targeting key molecules in disulfidptosis or combining metabolic interventions shows promising anticancer potential. However, current research still faces bottlenecks. These include unclear heterogeneity mechanisms and a lack of highly specific tools. Future efforts should establish precise classification systems, develop targeted drugs, and explore synergistic strategies combining immunotherapy to promote clinical translation.

ID: 42397925
Title: Pancreatic α cells are required for nutrient homeostasis by regulating dynamic β cell networks in islets.
Abstract: Pancreatic islets contain α, β, γ, and δ cells as sensors and actuators regulating glucose homeostasis. Despite the known importance of α cells, they are seemingly required for glucose tolerance only under metabolic stress. In an inducible model of α cell ablation in mice (GluDTR), glucose tolerance was considerably decreased by the addition of amino acids mimicking meals. Analysis of islet β cell secretion and electrical activities using microelectrode arrays (MEAs) detected only minor differences in GluDTR mice for glucose but revealed a major reduction upon addition of amino acids. Analysis of functional islet β cell networks by high-density MEA revealed leader regions in different locations, a high degree of synchrony, and the activation of large cell clusters. The characteristics of leading regions were preserved in GluDTR islets, but synchrony, cluster size, and signal propagation speed were largely reduced. Thus, even without metabolic stress, α cells are required for nutrient homeostasis by regulating the dynamics of β cell networks.

ID: 42398835
Title: Metabolic regulation-driven nanoparticles for tumor vulnerabilization and enhanced photodynamic therapy.
Abstract: Tumor cells exhibit pronounced metabolic plasticity, enabling adaptive compensation among metabolic pathways to sustain malignant growth and therapeutic resistance. To address this challenge, we develop a glutathione (GSH)-responsive peptide-based nanocomplex (siMCT4/CSE) that integrates dual metabolic intervention with photodynamic therapy (PDT) to induce metabolic collapse. The nanoplatform is constructed via the co-assembly of a disulfide-containing amphiphilic peptide and DSPE-PEG2k-FA, enabling the co-delivery of siRNA targeting monocarboxylate transporter 4 (siMCT4), the fatty acid β-oxidation (FAO) inhibitor Etomoxir, and chlorin e6 (Ce6). Following cellular internalization, elevated intracellular GSH triggers nanocomplex disassembly and synchronized release of therapeutic components. Mechanistically, siMCT4 inhibits lactate efflux, leading to intracellular lactate accumulation and feedback suppression of glycolysis, thereby limiting energy production, while Etomoxir blocks FAO by inhibiting carnitine palmitoyltransferase 1 (CPT1), restricting alternative energy supply. Under these metabolically constrained conditions, Ce6-mediated PDT generates reactive oxygen species (ROS), aggravating oxidative damage and amplifying metabolic stress. In 4 T1 tumor-bearing mice, this combined disruption of lactate efflux and FAO, together with PDT, drove tumor cells into severe metabolic imbalance, leading to significant tumor growth inhibition. Collectively, this strategy provides a metabolism-oriented therapeutic approach to overcome tumor metabolic adaptability and enhance antitumor efficacy.

ID: 42398868
Title: The central role of endoplasmic reticulum stress in Parkinson's disease and targeted therapeutic strategies.
Abstract: Parkinson's disease (PD) is a common neurodegenerative disorder. It is characterized by the progressive loss of dopaminergic neurons in the midbrain substantia nigra and the abnormal aggregation of α-synuclein. In recent years, ERS and the triggered UPR have been identified as a central role connecting multiple pathogenic factors in PD. This review systematically elaborates on the key pathological roles and molecular mechanisms of ERS in PD. In PD, various factors including genetic mutations, environmental toxins, and oxidative stress can disrupt ER homeostasis. These disruptions activate the UPR, which is mediated by the PERK, IRE1α, and ATF6 signaling pathways. A moderate UPR aims to restore cellular homeostasis. However, persistent or severe ERS can switch irreversibly to pro-apoptotic pathways, leading to neuronal death. More importantly, ERS interacts extensively with other PD-related pathological processes. It forms complex positive feedback loops with other core pathological processes in PD. These processes include the abnormal aggregation and propagation of α-synuclein, mitochondrial dysfunction, neuroinflammation, and impaired autophagic flux. Together, they drive the progressive neurodegeneration. Given its central role, targeting ERS has become a potential therapeutic strategy. This article focuses on discussing various intervention approaches, their research progress, and associated challenges. These include: UPR pathway-specific modulators; chemical chaperones; enhancers of protein degradation systems; existing drugs and natural products with ERS-modulating effects; neurotrophic factors and gene therapy; and traditional Chinese medicine. Finally, we discuss future research directions, including developing central nervous system-selective drugs, utilizing precision medicine for personalized treatment, and exploring combination therapies. The aim is to provide new perspectives for disease-modifying treatments of PD.

ID: 42399370
Title: Therapeutic targeting of the conserved region within the low-complexity domain of TDP-43 is neuroprotective and extends survival in amyotrophic lateral sclerosis mice.
Abstract: Autosomal dominant mutations in TARDBP, encoding TAR DNA-binding protein 43 (TDP-43), cause amyotrophic lateral sclerosis (ALS), and TDP-43 pathology is a hallmark of multiple aging-associated neurodegenerative diseases. Despite its pathological role, effective therapies remain limited by the lack of safe, potent molecules targeting TDP-43 neurotoxicity. Here we show that the conserved α-helical region spanning residues 320-340 (conserved region or CR) is a therapeutically actionable target for TDP-43 neurotoxicity. Deletion of CR markedly suppressed TDP-43-induced neuronal death. Structure-based virtual screening identified XL20, a brain-penetrant small molecule that engages CR and confers neuroprotection without affecting TDP-43 splicing activity. XL20 alleviated motor neuron loss, extended survival in TDP-43 p.Ala315Thr ALS mice and enhanced neuronal function in p.Gln331Lys induced pluripotent stem cell-derived human ALS motor neurons. Mechanistically, targeting CR suppressed TDP-43 mitochondrial localization and restored mitochondrial function, likely through liquid-liquid phase separation. Our findings highlight CR as a therapeutic target for TDP-43-associated neurodegeneration and support CR-binding small molecules as therapeutic candidates.

ID: 42401208
Title: Angiogenesis-related microRNAs and signalling pathways in canine mammary tumours.
Abstract: Angiogenesis, a hallmark of cancer, supports tumour growth and metastasis by establishing an abnormal vascular network, and microRNAs (miRNAs) regulate this process post-transcriptionally. Because evidence in canine mammary tumours (CMTs) remains limited, we profiled 24 putative pro- and anti-angiogenic miRNAs by RT-qPCR in benign and malignant CMTs compared with normal mammary glands, and we predicted angiogenesis-related targets using multiMiR followed by Gene Ontology and KEGG pathway enrichment analyses. Intratumoral angiogenesis was quantified as microvascular density (MVD) and endothelial area (EA) on Factor VIII-immunolabeled sections using QuPath. MVD and EA were higher in malignant than in benign CMTs and peaked in grade III carcinomas. Malignant CMTs showed a progressive shift towards a pro-angiogenic miRNA profile, with significant upregulation of pro-angiogenic miR-9, miR-20a, miR-98, miR-210, and miR-21(p < 0.05). Conversely, anti-angiogenic miRNA displayed a heterogenous, context-dependent expression pattern: miR-152-3p and miR-542-3p were downregulated in benign CMTs relative to normal mammary tissue, whereas miR-205 and miR-34a were upregulated in malignant CMTs (p < 0.05). In malignant CMTs, MVD correlated with EA (r = 0.8, p = 0.0003), EA correlated with miR-98 (r = 0.67, p = 0.006), and tumour size correlated with miR-210 (r = 0.58, p = 0.03). In benign tumours, EA correlated with miR-497 (r = 0.81, p = 0.02). Target prediction identified 16,910 genes, with pro- and anti-angiogenic miRNAs sharing 86.5% of predicted targets, indicating extensive regulatory overlap. KEGG enrichment highlighted 100 significantly enriched pathways (FDR < 0.05), including MAPK, PI3K-Akt, HIF-1, VEGF, and breast cancer signalling, with MAPK1 and MAPK3 among the most frequently targeted genes. Finally, miR-34a showed the best diagnostic performance for distinguishing benign from malignant CMTs. Overall, findings support a substantial contribution of miRNAs to angiogenic regulation in CMTs, strengthen the utility of the canine model in comparative breast cancer research, and highlight the potential of miRNA-based biomarkers for tumour stratification and anti-angiogenic targeting.

ID: 42404433
Title: Beyond motor neurons: peripheral TDP-43 pathology in skeletal muscle and intramuscular nerves in amyotrophic lateral sclerosis.
Abstract: Amyotrophic lateral sclerosis is a progressive neurodegenerative disease characterized by accumulation of the 43-kDa TAR DNA-binding protein (TDP-43). This neuropathological signature has been well documented within the CNS; however, recent findings indicate that the phosphorylated TDP-43 additionally deposits in peripheral tissues, including skeletal muscle and intramuscular nerves. These data warrant a change of view from a neurocentric perspective of amyotrophic lateral sclerosis pathogenesis towards a broader concept of TDP-43 proteinopathy extending both within and beyond the nervous system. In this review, we focus on current evidence supporting the presence of TDP-43 pathology in amyotrophic lateral sclerosis skeletal muscle, examining its topographic distribution, molecular characteristics and associations with intramuscular nerve bundles. We also discuss the susceptibility of intrinsic muscle cells, disrupted axonal transport and impairment in protein quality control. Phosphorylated TDP-43 pathology in muscle biopsies from amyotrophic lateral sclerosis patients has emerged as a promising tool in the early diagnosis of the disease. Moreover, we discuss the relevance of these findings to amyotrophic lateral sclerosis pathogenesis and potential therapeutic implications.