Alzheimer & Parkinson

α-synuclein transmission and propagation are hallmarks of synucleinopathies, yet the molecular mechanisms remain elusive. Using α-synuclein preformed fibrils as pathological seeds, we observed a gradual decline in neuronal transmission activity during serial propagation. Fibril polymorphisms were identified from the initial generation: mini-P, with higher neuronal seeding activity, and mini-S, which accelerated recombinant α-synuclein aggregation. Changes in their proportions during propagation...

Alzheimer's disease (AD) is a growing neurological disorder giving impact cognition and memory, posing a global health challenge with over 55 million individuals affected. It is the 7th foremost cause of dying worldwide, and its pervasiveness is expected to twofold in each five years, reaching 115 million by 2050. AD is characterized by neurofibrillary tangles, senile plaques, and oxidative stress, leading to synaptic failure and cognitive decline. Currently, there is no cure, and available...

Early, efficient Parkinson's disease (PD) tests may facilitate pre-symptomatic diagnosis and disease-modifying therapies. Here we report elevated levels of PD-specific transfer RNA fragments carrying a conserved sequence motif (RGTTCRA-tRFs) in the substantia nigra, cerebrospinal fluid and blood of patients with PD. A whole blood qPCR test detecting elevated RGTTCRA-tRFs and reduced mitochondrial-originated tRFs (MT-tRFs) segregated pre-symptomatic patients with PD from controls (area under the...

RNA editing is a posttranscriptional mechanism that targets changes in RNA transcripts to modulate innate immune responses. We report the role of astrocyte-specific, ADAR1-mediated RNA editing in neuroinflammation in Parkinson's disease (PD). We generated human induced pluripotent stem cell-derived astrocytes, neurons and cocultures and exposed them to small soluble alpha-synuclein aggregates. Oligomeric alpha-synuclein triggered an inflammatory glial state associated with Toll-like receptor...

Neurodegenerative disorders such as Alzheimer's disease and macular degeneration represent major sources of human suffering, yet factors influencing disease severity remain poorly understood. Sex has been implicated as one modifying factor. Here, we show that female sex is a risk factor for worsened outcomes in a model of retinal degeneration and that this susceptibility is caused by the presence of female-specific sex hormones. The adverse effect of female sex hormones was specific to diseased...

Human pluripotent stem cell (hPSC)-derived therapies are a realistic possibility for numerous disorders, including Parkinson's disease. While generating replacement neurons is achievable, immunosuppressive drug challenges, to prevent rejection, remain. Here we adopted a hPSC line (termed H1-FS-8IM), engineered to overexpress 8 immunomodulatory transgenes, to enable transplant immune evasion. In co-cultures, H1-FS-8IM PSC-derived midbrain neurons evaded rejection by T lymphocytes, natural killer...

This study explores the involvement of the subthalamic nucleus (STN) in executive functions, particularly cognitive flexibility, in Parkinson's disease (PD) patients. Utilizing a computerized Wisconsin Card Sorting Task (WCST) and local field potential (LFP) recordings from implanted deep brain stimulation (DBS) electrodes, we investigated task-specific neural dynamics. Behavioural results demonstrated increased error rates and prolonged response times in trials requiring set-shifting and rule...

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Based on genetic studies, lysosome dysfunction is thought to play a pathogenetic role in Parkinson's disease. Here we show that VPS13C, a bridge-like lipid-transport protein and a Parkinson's disease gene, is a sensor of lysosome stress or damage. Following lysosome membrane perturbation, VPS13C rapidly relocates from the cytosol to the surface of lysosomes where it tethers their membranes to the ER. This recruitment depends on Rab7 and requires a signal at the damaged lysosome surface that...

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Genetic engineering of microglial cells is a promising therapeutic avenue emerging with advancements in gene delivery techniques. Using a recently developed AAV capsid for efficient in vitro transduction we report the engineering of microglia with CARs (CAR-Mic) targeting phagocytosis of amyloid beta 1‒42 (Aβ42). Functional screening of seven CAR constructs in human iPSC-derived microglia revealed up to 6-fold increases in internalized Aβ relative to viral control. CAR-driven phagocytic...

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Variants in GBA1 resulting in decreased lysosomal glucocerebrosidase (GCase) activity are a common risk factor for Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Incomplete penetrance of GBA1 variants suggests that additional genes contribute to PD and DLB manifestation. By using a pooled genome-wide CRISPR interference screen, we identified copper metabolism MURR1 domain-containing 3 (COMMD3) protein, a component of the COMMD/coiled-coil domain-containing protein 22...

Protein aggregation and microglia-mediated neuroinflammation are the major contributors to the progression of neurodegeneration. Currently, available drugs for neurodegenerative diseases have limited efficacy and are associated with several side effects; suggesting a need to discover novel therapeutic agents. Therefore, we aim to evaluate the neuroprotective effects of C. asiatica against amyloid beta (Aβ) and lipopolysaccharides (LPS)-induced neurodegeneration using human microglia and neuronal...

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Recent research has established a strong link between metabolic abnormalities and an increased risk of dementia. In parallel, there is growing epidemiological evidence supporting the neuroprotective effects of antidiabetic medications against cognitive impairments. Among these, sodium-glucose co-transporter (SGLT2) inhibitors have emerged as pharmacological candidates with promising potential in alleviating the burden of age-related diseases, particularly neurodegenerative diseases (NDD). SGLT2...

Lipid dyshomeostasis and tau pathology are present in frontotemporal lobar degeneration (FTLD) and Alzheimer's disease (AD). However, the relationship between lipid dyshomeostasis and tau pathology remains unclear. We report that GRAM Domain Containing 1B (GRAMD1B), a nonvesicular cholesterol transporter, is increased in excitatory neurons of human neural organoids (HNOs) with the MAPT R406W mutation. Human FTLD, AD cases, and PS19 tau mice also have increased GRAMD1B expression. We show that...