Assessing the biomolecular landscape and dynamics of systemically circulating lipid-carrying particles

Separating lipid-carrying particles from blood is challenging and complicates the biological understanding and biomarker development of extracellular vesicles (EV) and lipoprotein particles (LPP). In this study, we fractionate serial blood plasma samples from breast cancer, ovarian cancer and HIV patients (n=36) by combining size-exclusion chromatography (SEC) and equilibrium density gradient centrifugation to assess the biomolecular composition and dynamics of systemically circulating EV and LPP. We demonstrate the analytical validity of blood plasma fractionation and reveal that EV carry a unique, dynamic and context-dependent protein composition, and miRNA and tRNA profile, which are not directly measurable in LPP and total blood plasma, respectively. In addition, we identify the compositional nature of the EV protein corona and provide a catalog of proteins associated with systemically circulating EV versus LPP. In conclusion, the implementation of blood plasma fractionation substantially advances the biological understanding and biomarker development of systemically circulating lipid-carrying particles.