Williams-Gray, C. H. | bioRxiv Science

bioRxiv2025

Nanoscopic tau aggregates in Parkinson's disease

Post-mortem tau pathology is frequently observed in Parkinsons disease (PD) using immunohistochemistry (IHC) to measure large inclusions, however, small protein aggregates that precede inclusions are considered a major driver of toxicity in neurodegenerative disease. We aimed to uncover the distribution of nanoscopic aggregates across six brain regions in post-mortem tissue from 14 PD and 15 controls using the single-molecule pull-down assay (SiMPull). In the hippocampus and amygdala, tau IHC and SiMPull were associated with advanced age in controls and dementia status in PD. Despite negligible tau IHC-labelled aggregates in the putamen, we identified a unique population of high-intensity nanoscopic tau aggregates for a subset of PD cases using SiMPull, ranging from 10-1,000 epitopes per aggregate and 30-1,000 nm in length. Previous evidence linking nigrostriatal tau pathology and motor deficits indicates that the nanoscopic tau aggregates identified in this study may contribute to striatal dysfunction in PD.

neuroscience↗

bioRxiv2019

Genome-wide association study of Parkinson's disease progression biomarkers in 12 longitudinal patients' cohorts

BackgroundSeveral reports have identified different patterns of Parkinsons disease progression in individuals carrying missense variants in the GBA or LRRK2 genes. The overall contribution of genetic factors to the severity and progression of Parkinsons disease, however, has not been well studied. ObjectivesTo test the association between genetic variants and the clinical features and progression of Parkinsons disease on a genome-wide scale. MethodsWe accumulated individual data from 12 longitudinal cohorts in a total of 4,093 patients with 25,254 observations over a median of 3.81 years. Genome-wide associations were evaluated for 25 cross-sectional and longitudinal phenotypes. Specific variants of interest, including 90 recently-identified disease risk variants, were also investigated for the associations with these phenotypes. ResultsTwo variants were genome-wide significant. Rs382940(T>A), within the intron of SLC44A1, was associated with reaching Hoehn and Yahr stage 3 or higher faster (HR 2.04 [1.58, 2.62], P-value = 3.46E-8). Rs61863020(G>A), an intergenic variant and eQTL for ADRA2A, was associated with a lower prevalence of insomnia at baseline (OR 0.63 [0,52, 0.75], P-value = 4.74E-8). In the targeted analysis, we found nine associations between known Parkinsons risk variants and more severe motor/cognitive symptoms. Also, we replicated previous reports of GBA coding variants (rs2230288: p.E365K, rs75548401: p.T408M) being associated with greater motor and cognitive decline over time, and APOE E4 tagging variant (rs429358) being associated with greater cognitive deficits in patients. ConclusionsWe identified novel genetic factors associated with heterogeneity of progression in Parkinsons disease. The results provide new insights into the pathogenesis of Parkinsons disease as well as patient stratification for clinical trials.

genetics↗