Brain and kidney Extracellular Vesicle Morphology and Complementary Brain proteomics after Inflammatory Challenge

Shape, size variation, and protein composition describe different properties of tissue extracellular vesicle (EV) preparations. We compared brain and kidney EV shape and size using transmission electron microscopy (TEM). We also assessed repeated protein detection and reanalyzed a deposited brain proteomics cohort, with attribution to its original source. The study used intracerebroventricular lipopolysaccharide (LPS) and an intravenous miRNA-associated EV formulation. Each group contained three biological samples, as labelled in the source data. Source morphometry summaries included 385 brain and 101 kidney profiles. Kidney circularity was 0.9225, 0.8977, and 0.9288 in the control, LPS, and treatment groups, respectively. The corresponding values for diameter quartile dispersion, a measure of size variation, were 0.2603, 0.5334, and 0.6018. Thus, near-control outline shape coexisted with persistent size variation. None of the six primary morphology tests remained significant after Holm correction. Independent recalculation confirmed 1,527 eligible rat protein accessions across individual searches. The complete quantitative matrix contained 953 features. The main peptide filter combined unique and razor peptides. A stricter analysis retained 916 features. PTGFRN and LAMB2 remained the only significant treatment-versus-LPS findings. In the main analysis, PTGFRN increased 14.71-fold (q = 0.0365), and LAMB2 increased 6.23-fold (q = 0.00585). Their LPS levels were already close to control values. Exploratory normalization used the geometric mean of four measured EV-associated markers. The resulting treatment-versus-LPS increases were 16.43-fold and 6.96-fold, respectively. These ratios support selective changes in relative protein representation within the recovered mixture. They do not establish protein copies per EV. Analysis of the full protein profile and calibration of the complete selection process did not support an overall return to control. This study compares morphology and composition as separate outcomes. It identifies membrane and matrix associations as priorities for validation. Original TEM measurements were unavailable, sample matching remained unresolved, and kidney proteomics were absent. These limitations prevent causal conclusions and individual-sample comparisons between morphology and protein composition.

This study contributes to exosome research by integrating particle morphology and proteomic analysis to characterize tissue-derived extracellular vesicle-enriched preparations following inflammation and miRNA-associated vesicle administration. The findings highlight that particle shape, size heterogeneity, and protein composition can follow different treatment-associated patterns, supporting their assessment as complementary features of exosome preparations. Selective enrichment of PTGFRN and LAMB2 prioritizes membrane and extracellular-matrix association for further investigation. This approach strengthens the interpretation of exosome characterization data and defines focused questions about particle identity, protein localization, and functional cargo delivery. It provides a foundation for evaluating how changes in recovered vesicle preparations relate to the biological activity of exosome-based interventions.