title: Comparative proteomics evaluation of plasma exosome isolation techniques and assessment of the stability of exosomes in normal human blood plasma.
abstract: Exosomes are nanovesicles released by a variety of cells and are detected in body fluids including blood. Recent studies have highlighted the critical application of exosomes as personalized targeted drug delivery vehicles and as reservoirs of disease biomarkers. While these research applications have created significant interest and can be translated into practice, the stability of exosomes needs to be assessed and exosome isolation protocols from blood plasma need to be optimized. To optimize methods to isolate exosomes from blood plasma, we performed a comparative evaluation of three exosome isolation techniques (differential centrifugation coupled with ultracentrifugation, epithelial cell adhesion molecule immunoaffinity pull-down, and OptiPrep(TM) density gradient separation) using normal human plasma. Based on MS, Western blotting and microscopy results, we found that the OptiPrep(TM) density gradient method was superior in isolating pure exosomal populations, devoid of highly abundant plasma proteins. In addition, we assessed the stability of exosomes in plasma over 90 days under various storage conditions. Western blotting analysis using the exosomal marker, TSG101, revealed that exosomes are stable for 90 days. Interestingly, in the context of cellular uptake, the isolated exosomes were able to fuse with target cells revealing that they were indeed biologically active.
authors.affiliation: Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia.
authors.forename: Hina
authors.initials: H
authors.lastname: Kalra
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Adda
authors.forename: Michael
authors.initials: M
authors.lastname: Liem
authors.forename: Ching-Seng
authors.initials: CS
authors.lastname: Ang
authors.forename: Adam
authors.initials: A
authors.lastname: Mechler
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Simpson
authors.forename: Mark D
authors.initials: MD
authors.lastname: Hulett
authors.forename: Suresh
authors.initials: S
authors.lastname: Mathivanan
mesh_terms: D015415:Biomarkers; D015153:Blotting, Western; D055354:Exosomes / Q000737:chemistry*; D006801:Humans; D013058:Mass Spectrometry; D010949:Plasma / Q000737:chemistry* / Q000166:cytology*; D020543:Proteome / Q000032:analysis* / Q000737:chemistry; D040901:Proteomics / Q000379:methods*; D014783:Viscosity
chemical_list: D015415:Biomarkers; D020543:Proteome
keywords: Animal proteomics; Biomarkers; Exosomes; Targeted drug delivery