Biology subjects

Ingelsson, M.

Publications and source records attributed to Ingelsson, M..

10 recordsLinked to original sources

bioRxiv2026

Differently sized soluble α-synuclein species from multiple system atrophy and Lewy body disease brains display different seeding propensities

Different conformations, or strains, of -synuclein (-syn) aggregates are believed to be responsible for the distinct seeding propensities, propagation profiles, and clinical presentations in Lewy body diseases (LBD) and multiple system atrophy (MSA). While biochemical properties and strain differences of insoluble deposits have been extensively characterized, the understanding of what influence soluble -syn species may have on these processes is limited to a small number of studies focusing on complex mixtures of soluble species or on a single - synucleinopathy. Given that soluble oligomers are considered highly pathologically relevant, we isolated and characterized the biochemical, seeding, and toxicity properties of size-fractionated soluble -syn species from MSA and LBD brains, comparing them to species from control brains without known neurological disease (Ctrl). We observed that levels of differently sized oligomers phosphorylated at Ser129, as well as soluble large oligomers (>450 kDa), were increased in LBD compared to both MSA and Ctrl brains. Nevertheless, species derived from MSA brain exhibited seeding activity across the spectrum of -syn species (oligomers, monomers, and truncated forms) in the seed amplification assay, whereas only oligomeric species (>150 kDa) from LBD cases were seeding-prone. In the HEK293 -syn (A53T)-YFP biosensor line, as well as in murine primary neurons, only large oligomers (>450 kDa) from MSA cases induced seeding and aggregation of -syn. Taken together, our study suggests that soluble -syn species derived from MSA and LBD brains show different biochemical, aggregation and seeding patterns, presumably due to strain variations of the respective oligomers. Our findings provide novel insight into the pathogenesis of different -synucleinopathies, which may guide us in the development of targeted therapeutics.

neuroscience↗

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

α-Synuclein purification significantly impacts seed amplification assay performance and consistency

-Synuclein seed amplification assays are a promising diagnostic tool for synucleinopathies such as Parkinsons disease and multiple system atrophy. Standardized conditions are required to ensure a high degree of inter- and intra-laboratory reproducibility when performing these assays. A significant issue that hinders the utility of seed amplification assays is the de novo aggregation propensity of the -synuclein substrate as well as inter-batch heterogeneity. While much work has focused on determining appropriate seed amplification assay buffer compositions as well as the type and amount of seed used, a robust comparison of -synuclein substrate purification methods has not been reported. We therefore compared the utility of recombinant -synuclein purified using four different methods as seed amplification assay substrates across two laboratories. Osmotic shock-purified -synuclein monomer substrate showed the lowest propensity for de novo aggregation, which translated into being the best substrate for seed amplification assay reactions seeded with -synuclein preformed fibrils or patient brain homogenates. Furthermore, osmotic shock -synuclein monomer showed the best inter-batch reproducibility compared to all other substrates tested. As -synuclein seed amplification assays continue to evolve and move towards adoption in the clinical realm, this work showcases the vital importance of standardizing the production and characterization of recombinant -synuclein substrate. We encourage the widespread adoption of osmotic shock -synuclein monomer as the universal substrate for seed amplification assays to maximize intra- and inter-laboratory reproducibility.

biochemistry↗

bioRxiv2025

Alternative splicing generates a Ribosomal Protein S24 isoform induced by neuroinflammation and neurodegeneration

Neuroinflammation, particularly that involving reactive microglia, the brains resident immune cells, is implicated in the pathogenesis of major neurodegenerative diseases. However, early markers of this process are in high demand. Multiple studies have reported changes in ribosomal protein (RP) expression during neurodegeneration, but the significance of these changes remains unclear. Ribosomes are evolutionarily conserved protein synthesizing machines, and although commonly viewed as invariant, accumulating evidence suggest functional ribosome specialization through variation in their protein composition. By analyzing cell type-specific translating mRNAs from mouse brains, we identify distinct RP expression patterns between neurons, astrocytes, and microglia, including neuron-specific RPs, Rpl13a and Rps10. We also observed complex expression relationships between RP paralogs and their canonical counterparts, suggesting regulated mechanisms for generating heterogeneous ribosomes. Analysis across brain regions revealed that Rplp0 and Rpl13a, commonly used normalization references, show heterogeneous expression, raising important methodological considerations for gene expression studies. Importantly, we show that Rps24, an essential ribosome component that undergoes alternative splicing to produce protein variants with different C-termini, exhibits striking cell type-specific isoform expression in brain. The Rps24c isoform is predominantly expressed in microglia and is increased by neuroinflammation caused by aging, neurodegeneration, or inflammatory chemicals. We verify increased expression of S24-PKE, the protein variant encoded by Rps24c, in brains with Alzheimers disease, Parkinsons disease, and Huntingtons disease, and relevant mouse models, using isoform-specific antibodies. These findings establish heterogeneous RP expression as a feature of brain cell types and identify Rps24c/S24-PKE as a novel marker for neuroinflammation and neurodegeneration.

neuroscience↗

bioRxiv2023

Cryo-EM Structures of Amyloid-β Fibrils from Alzheimer's Disease Mouse Models

The development of novel drugs for Alzheimers disease has proven difficult, with a high failure rate in clinical trials. Typically, transgenic mice displaying amyloid-{beta} peptide brain pathology are used to develop therapeutic options and to test their efficacy in preclinical studies. However, the properties of A{beta} in such mice have not been systematically compared to A{beta} from the patient brains. Here, we determined the structures of nine ex vivo A{beta} fibrils from six different mouse models by cryo-EM. We found novel A{beta} fibril structures in the APP/PS1, ARTE10, and tg-SwDI models, whereas the human familial type II fibril fold was found in the ARTE10, tg-APPSwe, and APP23 models. The tg-APPArcSwe mice showed an A{beta} fibril whose structure resembles the human sporadic type I fibril. These structural elucidations are key to the selection of adequate mouse models for the development of novel plaque-targeting therapeutics and PET imaging tracers. One Sentence SummaryCryo-EM structures of A{beta} fibrils extracted from brains of mouse models used for Alzheimers disease preclinical research are presented.

neuroscience↗

bioRxiv2022

Single-cell transcriptomics of resected human traumatic brain injury tissues reveals acute activation of endogenous retroviruses in oligodendrocytes

Traumatic brain injury (TBI) is a leading cause of chronic brain impairment and results in a robust, but poorly understood, neuroinflammatory response that contributes to the long-term pathology. We used snRNA-seq to study transcriptomic changes in different cell populations in human brain tissue obtained acutely after severe, life-threatening TBI. This revealed a unique transcriptional response in oligodendrocyte precursors and mature oligodendrocytes, including the activation of a robust innate immune response, indicating an important role for oligodendroglia in the initiation of neuroinflammation. The activation of an innate immune response correlated with transcriptional upregulation of endogenous retroviruses in oligodendroglia. This observation was causally linked in vitro using human glial progenitors, implicating these ancient viral sequences in human neuroinflammation. In summary, this work provides a unique insight into the initiating events of the neuroinflammatory response in TBI, which has new therapeutic implications.

neuroscience↗

bioRxiv2022

Size matters - the impact of nucleus size on results from spatial transcriptomics

Visium Spatial Gene Expression (ST) is a method combining histological spatial information with transcriptomics profiles directly from tissue sections. The use of spatial information has made it possible to discover novel modes of gene expression regulations. However, in the ST experiment, the nucleus size of cells may exceed the thickness of a tissue slice. This may, in turn, negatively affect comprehensive capturing the transcriptomics profile in a single slice, especially for tissues having large differences in the size of nuclei. Here, we defined the effect of Consecutive Slices Data Integration (CSDI) on results from spatial transcriptomic study of human postmortem brains. CSDI can be applied to investigate consecutive sections studied with ST in the human cerebral cortex, avoiding misinterpretation of spot clustering and annotation, increasing accuracy of cell recognition as well as improvement in uncovering the layers of grey matter in the human brain.

bioinformatics↗

bioRxiv2019

Loss of Y in leukocytes, dysregulation of autosomal immune genes and disease risks

Mosaic loss of chromosome Y (LOY) in leukocytes has been associated with many diseases, yet it remains unclear whether this form of clonal mosaicism exerts a direct physiological effect. Here we perform single-cell and bulk RNA sequencing in leukocytes, observing considerable variation in the rate of LOY across individuals, cell types and disease state. Cells with LOY demonstrated a profound degree of transcriptional dysregulation impacting [~]500 autosomal genes. These genes are preferentially involved in immune functions but also encode proteins with roles in other diverse biological processes. Our findings highlight a surprisingly broad role for chromosome Y challenging the view of it as a "genetic wasteland". Furthermore, they support the hypothesis that altered immune function in leukocytes is a mechanism directly linking LOY to disease.

immunology↗

bioRxiv2019

Intra-individual changes in the frequency of mosaic loss of chromosome Y over time estimated with a new method

BackgroundMosaic loss of chromosome Y (LOY) is the most common somatic mutation and is associated with all-cause mortality, non-haematological cancers and Alzheimers disease among other outcomes. The predominant method used for estimating LOY is the intensity data generated by SNP-arrays, which is difficult to interpret due to its logarithmic scale. Here we describe a new way to convert the LOY mosaicism into a non-logarithmic scale, which instead represents the percentage of affected cells.\n\nMethodsWe compared three independent LOY readouts from matched samples, generated by SNP-array, whole genome sequencing and droplet digital PCR. The SNP-array standardization was derived from this comparison and was applied in analyses of serially collected samples from a large cohort of aging men. The sampling was performed up to five times, spanning up to 22 years.\n\nResultsWe observed a higher correlation between the LOY measurements from SNP-array and the two other readouts when using the standardized, instead of the logarithmic, SNP-array data. We also observed a pronounced intra-individual variation of changes in the frequency of LOY within individual males over time.\n\nConclusionsDescribing LOY measurements generated from SNP-arrays in percentage of cells without the Y chromosome makes comparisons to WGS and ddPCR measurements more precise and easier to interpret. This standardization could be applied to the vast amount of SNP-array data already generated in the scientific community, allowing further discoveries of LOY associated disease and outcomes. Additionally, the frequency of LOY in this study changed profoundly within men over time, likely as a result of aberrant clonal expansions.

genetics↗

bioRxiv2019

Genetic predisposition to mosaic Y chromosome loss in blood is associated with genomic instability in other tissues and susceptibility to non-haematological cancers

Mosaic loss of chromosome Y (LOY) in circulating white blood cells is the most common form of clonal mosaicism, yet our knowledge of the causes and consequences of this is limited. Using a newly developed approach, we estimate that 20% of the UK Biobank male population (N=205,011) has detectable LOY. We identify 156 autosomal genetic determinants of LOY, which we replicate in 757,114 men of European and Japanese ancestry. These loci highlight genes involved in cell-cycle regulation, cancer susceptibility, somatic drivers of tumour growth and cancer therapy targets. Genetic susceptibility to LOY is associated with non-haematological health outcomes in both men and women, supporting the hypothesis that clonal haematopoiesis is a biomarker of genome instability in other tissues. Single-cell RNA sequencing identifies dysregulated autosomal gene expression in leukocytes with LOY, providing insights into how LOY may confer cellular growth advantage. Collectively, these data highlight the utility of studying clonal mosaicism to uncover fundamental mechanisms underlying cancer and other ageing-related diseases.

genetics↗