2026-08-12 | Structural basis of α-synuclein and DJ-1 complex.
The structure of α-synuclein is predominantly α-helical when bound to cellular membranes. However, under pathological or destabilizing conditions, this α-helical structure transitions into β-sheet-rich conformations, promoting protein aggregation and formation of Lewy bodies (LBs) in neurodegenerative disorders such as Parkinson's disease dementia (PDD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and Alzheimer's disease (AD). DJ-1 is a multifunctional brain protein acting as a chaperone or protease under oxidative stress and associating with abnormal protein aggregates. Although previous studies suggested DJ-1 inhibits α-synuclein aggregation, the structural basis remained elusive. Here, we elucidate the direct interaction between α-synuclein and DJ-1 using size-exclusion chromatography (SEC), fluorescence spectroscopy, and multi-angle light scattering (MALS), and determined their crystal structure by X-ray diffraction. The interaction interface was mapped to residues Q24, E28, A29, and N65 of α-synuclein and K148, N173, and Q180 of DJ-1, with Q180 forming strong hydrogen bonds (2.60-2.97 Å) with α-synuclein. Transmission electron microscopy (TEM) demonstrated DJ-1 suppresses α-synuclein fibril formation. Based on the structure, we designed a DJ-1-derived peptide (173-180) that significantly inhibited α-synuclein aggregation in TEM and ELISA assays, suggesting its potential as a therapeutic candidate for α-synucleinopathies.
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2026-08-05 | A single-domain antibody targets aggregation-prone region of α-synuclein to reduce synucleinopathy, rescue neurodegeneration and improve function.
Synucleinopathies are a group of neurodegenerative disorders characterized by the accumulation of aggregated α-synuclein (α-syn), including Parkinson's disease, Dementia with Lewy Bodies, and Multiple System Atrophy. These diseases are marked by locomotor and non-motor impairments, as well as mitochondrial dysfunction and the loss of dopaminergic (DA) neurons. We have developed several anti-α-syn single-domain antibodies (sdAbs) and demonstrated the diagnostic imaging potential of two of them and the acute therapeutic benefit of one in clearing α-syn in a mouse model. However, whether these sdAbs can suppress α-syn-mediated neuronal loss and locomotor impairment in vivo remains unclear. We evaluated the therapeutic potential of five anti-α-syn sdAbs to clear pathological α-syn in mouse neuronal culture and then demonstrated their in vivo efficacy in a Drosophila model of synucleinopathy. The sdAbs differed in their efficacy to lower levels of phospho-serine 129 α-syn, prevent loss of DA neurons, alleviate mitochondrial dysfunction, improve motor function, and prolong survival in synucleinopathy flies. The most effective sdAb, 2H1, has not been reported before. It binds strongly to the aggregation prone region of α-syn and robustly improves all these disease parameters. Additionally, that sdAb is associated with α-syn in the fly neurons, as shown through proximity dependent turboID biotinylation assays. The sdAb-turboID also biotinylated α-syn-associated proteins involved in synapse/vesicle trafficking pathways, pinpointing the location of their intracellular interaction. Our findings provide an insight into the therapeutic mechanism of action of these sdAbs and strongly support their clinical development.
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2026-07-25 | Multiple system atrophy: cure and care.
Multiple system atrophy (MSA) is a rare and rapidly progressive neurodegenerative disorder characterized by a variable combination of autonomic failure, parkinsonism, and cerebellar ataxia, with a median survival of 8-10 years from symptom onset. Its aetiology remains poorly understood, as most cases are sporadic and environmental contributors remain unclear. Neuropathologically, MSA is defined by the accumulation of α-synuclein within oligodendroglial cells, forming glial cytoplasmic inclusions that drive widespread neurodegeneration in striatonigral and olivopontocerebellar systems. Recent advances in diagnostic criteria and biomarker development have improved disease recognition; however, early diagnosis remains challenging, particularly during the prodromal phase, when clinical features overlap with other α-synucleinopathies. Advances in fluid biomarkers and multimodal imaging are expected to facilitate earlier detection, improve diagnostic accuracy, and provide more robust tools for monitoring disease progression. Therapeutic development has largely focused on targeting α-synuclein pathology, but these approaches have not yet demonstrated consistent clinical benefit, highlighting the biological complexity of MSA. In the absence of curative treatments, management remains largely supportive, aimed at symptom control, particularly addressing autonomic dysfunction and motor impairment. Emerging care models, including telemedicine and multidisciplinary management, are reshaping clinical practice and may improve access to specialized care. Bridging advances in pathophysiology with patient-centred care will be essential for improving outcomes in MSA.
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2026-07-20 | Mechanism-Based Therapy With Ampreloxetine for Neurogenic Orthostatic Hypotension in Multiple System Atrophy: A Randomized Withdrawal Trial.
Degeneration of the central autonomic network with relative sparing of peripheral autonomic neurons underlies neurogenic orthostatic hypotension in patients with multiple system atrophy (MSA). Ampreloxetine, a novel, selective, norepinephrine (NE) reuptake inhibitor, allows once-daily dosing to precisely target residual peripheral autonomic neurons. Based on the hypothesis that patients with MSA would be most responsive and the substantial unmet need for symptomatic therapy in this population, an MSA subgroup analysis was prespecified. We conducted a run-in 4-week, parallel-group, randomized controlled trial (SEQUOIA), followed by a pivotal enriched randomized withdrawal (RW) trial with 16-week open-label treatment and 6 weeks of 1:1 RW (REDWOOD). Inclusion criteria for the MSA subgroup included (1) probable or possible MSA, (2) 3-minute orthostatic blood pressure (BP) fall >20/10 mm Hg, and (3) dizziness or lightheadedness score >4 points. Outcome measures included self-reported symptom burden captured on the 10-item OH Questionnaire (OHQ). Differences were analyzed using logistic regression and mixed-model repeated measures analysis. Seventy-three patients with MSA entered the program (mean age 63 years old [range: 43-80], 52% male). Both SEQUOIA and REDWOOD did not meet their primary endpoints. In REDWOOD, 40 (61%) fulfilled enrichment criteria and were randomized. After 16-week open-label, OHQ symptom assessment (OHSA) composite domain scores improved 2.6 ± (SD = 2.1) points from pretreatment. The proportion of participants with treatment failure at week 6 of RW treatment period was 40% in the placebo arm and 15% in the ampreloxetine arm (p = 0.11). In secondary endpoints, at week 6 of RW, symptoms remained stable in the ampreloxetine group, but worsened on placebo (mean difference OHSA composite: -1.6 points ± 0.5; p = 0.0056, minimal clinically important worsening = 0.7-1.1 points). Standing for a short time favored ampreloxetine (-2.0 points ± 0.8; p = 0.015). Standing BP remained unchanged from open-label in the ampreloxetine group (systolic: 5.6 ± 4.1; diastolic: 3.7 ± 2.9 [SE] mm Hg) but fell after placebo withdrawal (systolic: -10.0 ± 4.5; diastolic: -6.0 ± 3.1 mm Hg). The catecholamine profile was consistent with NE transporter inhibition. There were no observed increases in supine BP. In a prespecified subgroup analysis of MSA participants in the REDWOOD trial, patients randomized to placebo worsened, whereas those who were randomized to treatment maintained their open-label level of function. REDWOOD trial, NCT03829657; first submitted to registry January 10, 2019; first participant enrolled February 22, 2019. SEQUOIA trial, NCT03750552; first submitted to registry November 20, 2018; first participant enrolled January 24, 2019. See ClinicalTrials.gov for full-protocol and statistical analysis plan. This study provides Class III evidence that in patients with MSA who had symptomatic benefit on orthostatic hypotension with ampreloxetine, there was no difference in the odds of treatment failures between those maintained on ampreloxetine and those withdrawn to placebo.
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2026-07-16 | Development of an RNA aptamer as a therapeutic agent for synucleinopathies.
The aggregation of α-synuclein (αSyn), a 140-mer protein, has been implicated in the pathogenesis of Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies. KTKEGV pseudo-repeats (KRs) in the sequence of αSyn are key mediators of its prion-like propagation and neurodegeneration. Despite the availability of symptomatic treatments, no current therapy effectively delays disease progression. Here we report a 77-nucleotide RNA aptamer called 1R6, obtained through in vitro selection, that binds with high affinity and selectivity to αSyn1-95. 1R6 significantly inhibits αSyn oligomerization and β-sheet-rich fibril assembly and promotes disaggregation of preformed fibrils. Additionally, 1R6 suppresses αSyn seeding, as determined by a FRET-based biosensor-cell assay. Cellular studies reveal that 1R6 co-transfection completely prevents αSyn-induced cytotoxicity. To assess the protective effects of 1R6 in vivo, we use a Drosophila melanogaster model expressing human αSyn in neurons. Flies fed 1R6 show improved locomotor activity, reduced photoreceptor degeneration, and decreased αSyn levels in the head. Structural characterization using 1H-15N heteronuclear multiple quantum correlation nuclear magnetic resonance experiments demonstrates that 1R6 targets KR motifs, a finding further supported by in silico simulations. Our findings support further development of RNA aptamers, such as 1R6, including evaluation of efficacy, stability, delivery, and immune responses in mammalian systems, highlighting their potential as therapeutic candidates for synucleinopathies.
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