Aggregation by lectins as an approach for exosome isolation from biological fluids: Validation for proteomic studies

Abstract

Exosomes, a special type of microparticles produced by cells, are currently of considerable interest for researchers. The term “exosomes” denotes extracellular vesicles of less than 120 nm in size derived from intracellular multivesicular bodies. Multiple studies that address the distinctive features of exosome structure and biochemical composition in various pathological states imply the possibility of development of novel diagnostic techniques based on the detection of changes in the pool of proteins and nucleic acids transported by exosomes. However, methods for isolation and investigation of exosomes are rather difficult to develop because of a small size of these vesicles. A novel approach for preparative-scale isolation of exosomes based on the phenomenon of binding and aggregation of these particles in the presence of lectins has been put forward in the present study. The method developed is relatively cost-effective, allows for the isolation of exosomes from various biological fluids, and has been validated for the subsequent analysis of the protein composition of the exosomes in view of the possible clinical applications. The validation showed that the sedimentation of lectin-aggregated exosomes is a suitable approach for the isolation of these microvesicles from the complete conditioned culture medium in a research-laboratory setup.