FUS-driven zebrafish model of ALS identifies tribenzylamine as a candidate modulator of ALS-associated pathology.

Targeting TDP-43 in sporadic amyotrophic lateral sclerosis

Intrabody B1 targeting TDP-43 modulates neuroinflammatory and metabolic pathways in a preclinical ALS model

TDP-43 pathology is a hallmark of Amyotrophic Lateral Sclerosis (ALS), yet no therapeutic strategy effectively targets its upstream molecular consequences. Here, we investigated whether the anti-TDP-43 intrabody scFv B1 modulates neuroinflammatory and metabolic pathways in a preclinical ALS model, and whether these effects translate into functional benefit after symptom onset. Using phage display, we previously identified single-chain variable fragments (scFvs) binding TDP-43, including the candidate therapeutic scFv B1. In NSC-34 motor neuron-like cells overexpressing human wildtype TDP-43, B1 reduced NF-κB activation, consistent with disruption of TDP-43–driven inflammatory signaling. For in vivo assessment, B1 was delivered via AAV-CAP.B10 after symptom onset in the hTDP-43(WTxA315T) transgenic mouse model, enabling neuro-specific expression. Two cohorts were analyzed - longitudinal (nine months) and terminal (six months post-treatment) - through behavioral testing, PET imaging, metabolomics, transcriptomics, and plasma biomarker analyses. B1 achieved robust CNS expression and modulated several disease-relevant molecular pathways. RNA-sequencing revealed attenuation of NF-κB–related inflammatory signatures and partial normalization of metabolic and trophic gene expression. Metabolomic profiling identified shifts toward wild-type-like levels in oxidative stress, mitochondrial, and membrane phospholipid metabolites. Despite these molecular effects, symptomatic B1 administration did not improve motor behavior or reduce plasma neurofilament light chain (NfL) concentrations. Notably, plasma TDP-43 levels were stabilized, indicating systemic target engagement. Collectively, scFv B1 modulates upstream pathogenic processes associated with TDP-43 proteinopathy but is insufficient to reverse established neurodegeneration after symptom onset, underscoring the need for earlier and likely combinatorial intervention strategies in ALS.

HDAC6 inhibition alleviates mitochondrial trafficking in models of Charcot-Marie-Tooth disease type 2A

Charcot-Marie-Tooth disease (CMT) is a group of inherited progressive conditions affecting distal motor and sensory neurons, leading to muscle weakness, pain, and loss of sensation in limbs. CMT type 2A (CMT2A) is the most common form of axonal CMT and is associated with a more severe clinical manifestation. However, there are no treatments currently available. To investigate disease mechanisms and facilitate treatment discovery, we developed an in vitro model for CMT2A by introducing the patient-specific MFN2R94Q/+ variant into human embryonic stem cells (hESCs). Isogenic variant and wild-type hESCs differentiated into spinal motor neurons with similar efficiency and gave rise to functional motor neurons in vitro. However, MFN2R94Q/+ spinal motor neurons displayed impaired mitochondrial trafficking, resulting in altered distribution of mitochondria in axons. Unbiased quantitative proteomic profiling of the endogenous MFN2 interactome revealed dose-dependent remodelling by the R94Q variant across 412 proteins, highlighting candidate mechanisms in disease pathology. Importantly, we showed that mitochondrial trafficking defects could be alleviated by treatment with an HDAC6 inhibitor. Chemical inhibition of HDAC6 also rescued the motor phenotype in a zebrafish CMT2A model. Taken together, our study reveals a variant-specific insight into CMT2A disease mechanisms and confirms HDAC6 as a promising target for further therapeutic development.

Targeting astrocyte-mediated neurotoxicity induced by ALS/FTD-associated RNA binding proteins.

BACKGROUND Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative disorders characterized by reactive astrocytes that contribute to neuronal injury through TAR DNA-binding protein 43 (TDP-43)-or fused in sarcoma (FUS)-driven neuroinflammatory signaling. Dehydrocostus lactone (DHE), a blood-brain barrier-permeable sesquiterpene lactone with established anti-inflammatory activity, represents a promising but unexplored therapeutic candidate for ALS/FTD. METHODS The therapeutic effects of DHE were evaluated in primary mouse and human astrocytes expressing ALS/FTD-associated RNA-binding protein pathology, ALS patient-derived fibroblasts, and primary cortical neurons exposed to astrocyte-conditioned medium. Drosophila models expressing mutant FUS or TDP-43 in glial cells were used to assess locomotor performance and survival. Molecular analyses examined nuclear factor kappa B (NF-κB) signaling, nuclear factor erythroid 2-related factor 2 (NRF2)-dependent antioxidant responses, protein aggregation, mitochondrial function, and inflammatory mediator production. Plasma concentrations of inflammatory cytokines and chemokines were measured in patients with sporadic ALS. RESULTS DHE exerted neuroprotective effects through a dual mechanism involving suppression of NF-κB-dependent inflammatory signaling and activation of NRF2-mediated antioxidant pathways in astrocytes exhibiting FUS or TDP-43 proteinopathy. DHE attenuated astrocyte-mediated neurotoxicity and improved neuronal mitochondrial function in conditioned-medium assays. In addition, DHE reduced pathological FUS accumulation in FUS P525L-expressing astrocytes and in stress-challenged patient-derived fibroblasts. In Drosophila models, DHE significantly improved locomotor function and extended survival. Translationally, the chemokines CXCL10, CCL3, and CCL19 were elevated in plasma from patients with ALS, were induced by FUS or TDP-43 pathology in astrocytes, and were suppressed by DHE treatment, supporting the clinical relevance of the inflammatory pathways targeted by DHE. CONCLUSION DHE mitigates astrocyte-driven neurotoxicity associated with ALS/FTD-related RNA-binding protein pathology by suppressing inflammatory signaling and enhancing antioxidant defense mechanisms. The consistent therapeutic effects observed across mouse and human cellular models, patient-derived samples, and in vivo Drosophila models support further investigation of DHE as a potential therapeutic strategy for ALS/FTD and highlight astrocyte-mediated signaling pathways as actionable targets in neurodegenerative disease.

Rotenone Exposure in Zebrafish Parkinson's Disease Model Reveals NURR1-TOP2B Dysregulation and Gut-Brain Axis-Associated Pathology.

Parkinson's disease (PD) is a progressive neurodegenerative disorder in which early gastrointestinal dysfunction and oxidative stress are increasingly implicated through the gut-brain axis. Zebrafish (Danio rerio) offer a tractable model for PD research; However, to our knowledge, there is currently no consensus on the rotenone concentration that effectively mimics both brain and gut pathology, leaving the dose required to induce integrated central-peripheral pathology unresolved. Adult zebrafish were exposed to 2.5 or 5µg/L rotenone for 28 days, and behavioral, biochemical, histological, and transcriptional changes were assessed in the brain and intestine. Rotenone induced concentration-dependent impairments in locomotion, anxiety-like behavior, and cognition, with pronounced deficits at 5µg/L. Histopathological damage in both the brain and intestine was observed at 2.5 & 5µg/L. Oxidative stress was evident, with elevated reactive oxygen species (ROS) levels in the brain at both concentrations and in the intestine only at 5µg/L, accompanied by increased lipid peroxidation (LPO) at the higher concentration. Antioxidant enzyme activities, including superoxide dismutase (SOD) and glutathione peroxidase (GPx), were significantly disrupted. Transcriptional analysis revealed upregulation of γ1-synuclein and top2b alongside downregulation of nr4a2a (Nurr1) in both tissues. Pro-inflammatory cytokines il6 and tnfa were also markedly elevated. In conclusion, these findings establish 5µg/L rotenone as an optimized exposure for inducing reproducible, systemically integrated PD-like pathology in zebrafish and underscore NURR1-TOP2B dysregulation as a molecular correlate of gut-brain axis-associated dysfunction.

The Neuroprotective Effect of Cdc42 Inhibition in the G93A Mutant hSOD1 Mouse Model of ALS

It is suggested that Cdc42 inhibition can preserve neuromuscular structure and motor function in ALS, even in the absence of prolonged survival, and Cdc42 is identified as a novel contributor to ALS pathogenesis and a promising therapeutic target for slowing functional decline.