Biology subjects

Rosen, I.

Publications and source records attributed to Rosen, I..

3 recordsLinked to original sources

bioRxiv2026

CytoLight: A Rapid and Versatile Fluorescent-Based Labeling Method for Extracellular Vesicle Characterization and Tracking

Efficient, aggregation-free extracellular vesicles (EVs) labeling is essential for studying their dynamics in-vitro and in-vivo. However, traditional dyes introduce limitations including aggregation, membrane intercalation, fluorescence transfer and inconsistent performance across EV sources thus distorting quantification, altering surface properties and confounding uptake and biodistribution analyses. Here, we systematically evaluated CytoLight, a luminal dye traditionally used for live-cell imaging, as an alternative for EV quantification, characterization, uptake analysis and in-vivo tracking, benchmarking it against PKH26, CFSE and ExoBrite across multiple platforms. CytoLight generated stable, intravesicular fluorescence without aggregation or membrane alteration, eliminating artifacts characteristic of conventional dyes. Using fluorescence-NTA and single-EV flow cytometry, CytoLight showed more consistent labeling across EV types than CFSE or ExoBrite, while avoiding PKH-related micelle-driven artifacts and exhibited compatibility with CD81 dual-detection. In uptake assays, CytoLight produced EV-specific endocytosis-dependent internalization signals exceeding labeled-BPS/protein controls. In-vivo, CytoLight-labeled EVs enabled fluorescent biodistribution mapping showing conventional EV tropism patterns distinguishable from labeled-PBS controls. These findings establish CytoLight as an effective, aggregation-free EV-labeling strategy. Its stability, specificity, compatibility with single-EV platforms and reliable performance in both cellular uptake and biodistribution studies position CytoLight as a practical, scalable alternative to current dyes, providing a stronger foundation for standardized and reproducible EV research.

cell biology↗

bioRxiv2025

Clonal Hematopoiesis Mutations Increase Risk of Alzheimer's Disease with APOE ϵ3/ϵ3 Genotype

Clonal hematopoiesis of indeterminate potential (CHIP) represents clonal expansion of blood cells, and increases the risk of hematological malignancies and cardiovascular disorders. Recent studies have studied CHIP mutations in individuals with Alzheimers disease (AD), but it is unclear whether their role in AD pathogenesis is protective, detrimental, or neutral. In this study, we used molecular-barcoded deep gene panel sequencing ([~]400X) to examine CHIP mutations in 298 blood samples from AD and neurotypical individuals 60 years and older. The AD patients exhibited a significantly higher burden of CHIP mutations compared to the age-matched controls (p < 2e-7, odds ratio (OR) = 2.89), particularly in low-frequency variants often not captured by standard whole exome or whole genome sequencing (WGS). This increase was driven by individuals with the APOE {varepsilon}3/{varepsilon}3 genotype and absent in {varepsilon}4 carriers. Analysis of an independent dataset from the Alzheimers Disease Sequencing Project (ADSP), comprised of WGS data from [~]30,000 individuals, confirmed increased CHIP mutations in AD versus control (p < 0.02, OR = 1.32), again driven by individuals with APOE {varepsilon}3/{varepsilon}3 genotype. CHIP mutations in AD patients also showed stronger positive selection than in controls. Our results indicate that AD patients show significantly more CHIP mutations in their blood than controls, involving more than one third of AD patients, and contributing to AD risk through a mechanism independent of APOE {varepsilon}4.

genetics↗

bioRxiv2024

Somatic cancer driver mutations are enriched and associated with inflammatory states in Alzheimer's disease microglia

Alzheimers disease (AD) is an age-associated neurodegenerative disorder characterized by progressive neuronal loss and pathological accumulation of the misfolded proteins amyloid-{beta} and tau1,2. Neuroinflammation mediated by microglia and brain-resident macrophages plays a crucial role in AD pathogenesis1-5, though the mechanisms by which age, genes, and other risk factors interact remain largely unknown. Somatic mutations accumulate with age and lead to clonal expansion of many cell types, contributing to cancer and many non-cancer diseases6,7. Here we studied somatic mutation in normal aged and AD brains by three orthogonal methods and in three independent AD cohorts. Analysis of bulk RNA sequencing data from 866 samples from different brain regions revealed significantly higher ([~]two-fold) overall burdens of somatic single-nucleotide variants (sSNVs) in AD brains compared to age-matched controls. Molecular-barcoded deep (>1000X) gene panel sequencing of 311 prefrontal cortex samples showed enrichment of sSNVs and somatic insertions and deletions (sIndels) in cancer driver genes in AD brain compared to control, with recurrent, and often multiple, mutations in genes implicated in clonal hematopoiesis (CH)8,9. Pathogenic sSNVs were enriched in CSF1R+ microglia of AD brains, and the high proportion of microglia (up to 40%) carrying some sSNVs in cancer driver genes suggests mutation-driven microglial clonal expansion (MiCE). Analysis of single-nucleus RNA sequencing (snRNAseq) from temporal neocortex of 62 additional AD cases and controls exhibited nominally increased mosaic chromosomal alterations (mCAs) associated with CH10,11. Microglia carrying mCA showed upregulated pro-inflammatory genes, resembling the transcriptomic features of disease-associated microglia (DAM) in AD. Our results suggest that somatic driver mutations in microglia are common with normal aging but further enriched in AD brain, driving MiCE with inflammatory and DAM signatures. Our findings provide the first insights into microglial clonal dynamics in AD and identify potential new approaches to AD diagnosis and therapy.

genomics↗