Biology subjects

So, R. W. L.

Publications and source records attributed to So, R. W. L..

5 recordsLinked to original sources

bioRxiv2026

α-Synuclein strain homogeneity in multiple system atrophy clinical subtypes

Conformationally distinct strains of -synuclein aggregates are believed to contribute to the clinical and pathological diversity observed among synucleinopathies such as multiple system atrophy (MSA) and Parkinsons disease. Cases of MSA can be classified into two distinct clinical subtypes: the cerebellar variant, MSA-C, and the parkinsonian variant, MSA-P. To assess whether distinct -synuclein strains may be present in individuals with MSA-C versus MSA-P, we characterized the conformational and seeding properties of -synuclein aggregates in various brain regions from MSA-C and MSA-P patients and performed propagation studies in M83 transgenic mice. Biochemical fingerprinting of -synuclein aggregates using limited proteolysis and a conformational stability assay failed to reveal differences between MSA-C and MSA-P either before or after propagation in mice. Similarly, using brain extracts from either MSA patients or MSA-inoculated mice, MSA-C and MSA-P -synuclein aggregates exhibited indistinguishable seeding attributes in a seed amplification assay. Finally, no differences were observed in either the kinetics of disease progression or the extent of cerebral -synuclein deposition in M83 mice inoculated with either MSA-C or MSA-P, regardless of the brain region from which the injected -synuclein aggregates were derived. These results suggest that MSA clinical subtypes are unlikely to arise due to distinct -synuclein strains. Instead, our findings support a model in which the same -synuclein strain initially forms in different brain regions, leading to differences in disease manifestation.

neuroscience↗

bioRxiv2025

Stochastic Misfolding Drives the Emergence of Distinct α-Synuclein Strains

The existence of -synuclein conformational strains provides a potential explanation for the clinical and pathological differences among synucleinopathies such as Parkinsons disease and multiple system atrophy. However, how distinct -synuclein strains are formed in vivo remains unknown. Here, we examined whether unique strains of self-propagating -synuclein aggregates can arise within a consistent molecular environment. Unexpectedly, we observed conformational heterogeneity between individual preparations of -synuclein pre-formed fibrils (PFFs) generated by polymerizing recombinant wild-type or A53T-mutant human -synuclein under identical conditions. Moreover, we found that -synuclein aggregates formed spontaneously in the brains of a transgenic synucleinopathy mouse model were conformationally diverse, leading to the identification of three distinct disease subtypes. Propagation of putative PFF- and brain-derived -synuclein strains in mice initiated several distinct synucleinopathies, characterized by differences in disease onset times, cerebral -synuclein deposition patterns, and the conformational attributes of -synuclein aggregates. The conformational diversity of -synuclein aggregates across PFF preparations and between the brains of individual transgenic mice demonstrates that -synuclein can spontaneously form multiple self-propagating strains within an identical environment both in vitro and in vivo. This suggests that stochastic misfolding into distinct aggregate structures drives the emergence of -synuclein strains and implies that the intrinsic variability of common synucleinopathy research tools must be considered when designing and interpreting experiments.

neuroscience↗

bioRxiv2024

α-Synuclein strain propagation is independent of cellular prion protein expression in transgenic mice

The cellular prion protein, PrPC, has been postulated to function as a receptor for -synuclein, potentially facilitating cell-to-cell spreading and/or toxicity of -synuclein aggregates in neurodegenerative disorders such as Parkinsons disease. To test this hypothesis, we compared the propagation behavior of two different -synuclein aggregate strains in M83 transgenic mice that either expressed or did not express PrPC. Following intracerebral inoculation with the S or NS strain, the presence of PrPC had minimal influence on -synuclein strain-specified attributes such as the kinetics of disease progression, the extent of cerebral -synuclein deposition, selective targeting of specific brain regions and cell types, the morphology of induced -synuclein deposits, and the structural fingerprints of protease-resistant -synuclein aggregates. Likewise, there were no appreciable differences in disease manifestation between PrPC-expressing and PrPC-lacking M83 mice following intraperitoneal inoculation of the S strain. Interestingly, intraperitoneal inoculation with the NS strain resulted in two distinct disease phenotypes, indicative of -synuclein strain evolution, but this was also independent of PrPC expression. Overall, these results suggest that PrPC plays at most a minor role in the propagation, neuroinvasion, and evolution of -synuclein strains. Thus, other putative receptors or cell-to-cell propagation mechanisms may play a larger role in the spread of -synuclein aggregates during disease.

neuroscience↗

bioRxiv2023

Upregulated pexophagy limits the capacity of selective autophagy

Selective autophagy is an essential mechanism to maintain organelle integrity and cellular homeostasis through the constant recycling of damaged or superfluous components. While distinct selective autophagy pathways mediate the degradation of diverse cellular substrates including organelles and pathogens, whether these distinct pathways can influence one another remains unknown. We address this question here using pexophagy, the autophagic degradation of peroxisomes, as a model. We demonstrate in cells that upregulated pexophagy exhausts selective autophagy and limits the degradation of both mitochondria and protein aggregates. We confirmed this finding in the pexophagy-mediated form of Zellweger Spectrum Disorder, a rare disease characterized by peroxisome dysfunction. Further, we extend the generalizability of limited selective autophagy by determining that increased aggrephagy reduces pexophagy using a model of Huntingtons Disease. Our findings suggest that the degradative capacity of selective autophagy can become limited by an increased substrate load.

cell biology↗

bioRxiv2021

A novel approach to evaluate alpha-synuclein seeding shows a wide heterogeneity in multiple system atrophy

Several in vitro and in vivo findings have consistently shown that -synuclein derived from multiple system atrophy (MSA) subjects has more seeding capacity than Parkinsons disease-derived -synuclein. However, reliable detection of -synuclein derived from MSA using seeded amplification assays, such as the Real-Time Quaking-induced Conversion, has remained challenging. Here we demonstrate that the interaction of the Thioflavin T dye with -synuclein from MSA and Parkinsons disease patients can be modulated by the type of salt, pH, and ionic strength used to generate strain-specific reaction buffers. Employing this novel approach, we have generated a streamlined Real-Time Quaking-induced Conversion assay capable of categorizing MSA brains according to their -synuclein seeding behavior, and to unravel a previously unrecognized heterogeneity in seeding activity between different brain regions of a given individual that goes beyond immunohistochemical observations and provide a framework for future molecular subtyping of MSA.

neuroscience↗