Ultrafiltration combined with size exclusion chromatography efficiently isolates extracellular vesicles from cell culture media for compositional and functional studies

Sci Rep. 2017 Nov 10;7(1):15297. doi: 10.1038/s41598-017-15717-7.

Abstract

Appropriate isolation methods are essential for unravelling the relative contribution of extracellular vesicles (EVs) and the EV-free secretome to homeostasis and disease. We hypothesized that ultrafiltration followed by size exclusion chromatography (UF-SEC) provides well-matched concentrates of EVs and free secreted molecules for proteomic and functional studies. Conditioned media of BEAS-2B bronchial epithelial cells were concentrated on 10 kDa centrifuge filters, followed by separation of EVs and free protein using sepharose CL-4B SEC. Alternatively, EVs were isolated by ultracentrifugation. EV recovery was estimated by bead-coupled flow cytometry and tuneable resistive pulse sensing. The proteomic composition of EV isolates and SEC protein fractions was characterized by nano LC-MS/MS. UF-SEC EVs tended to have a higher yield and EV-to-protein rate of purity than ultracentrifugation EVs. UF-SEC EVs and ultracentrifugation EVs showed similar fold-enrichments for biological pathways that were distinct from those of UF-SEC protein. Treatment of BEAS-2B cells with UF-SEC protein, but not with either type of EV isolate increased the IL-8 concentration in the media whereas EVs, but not protein induced monocyte adhesion to endothelial cells. Thus, UF-SEC is a useful alternative for ultracentrifugation and allows comparing the proteomic composition and functional effects of EVs and free secreted molecules.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, Gel*
  • Culture Media / chemistry
  • Epithelial Cells / chemistry*
  • Epithelial Cells / metabolism*
  • Extracellular Vesicles / chemistry*
  • Humans
  • Sepharose / analogs & derivatives
  • Sepharose / chemistry
  • THP-1 Cells
  • Ultrafiltration

Substances

  • Culture Media
  • Sepharose CL 4B
  • Sepharose