Development of a quantitative method to measure EV uptake

Sci Rep. 2019 Jul 19;9(1):10522. doi: 10.1038/s41598-019-47023-9.

Abstract

The outstanding potential of Extracellular Vesicles (EVs) in medicine, deserves a detailed study of the molecular aspects regulating their incorporation into target cells. However, because EV size lies below the limit of resolution of optical techniques, quantification together with discrimination between EV binding to the target cell and uptake is usually not completely achieved with current techniques. Human tetraspanins CD9 and CD63 were fused to a dual EGFP-Renilla-split tag. Subcellular localization and incorporation of these fusion proteins into EVs was assessed by western-blot and fluorescence microscopy. EV binding and uptake was measured using either a classical Renilla substrate or a cytopermeable one. Incubation of target cells expressing DSP2 with EVs containing the complementary DSP1 portion could not recover fluorescence or luciferase activity. However, using EVs carrying the fully reconstituted Dual-EGFP-Renilla protein and the cytopermeable Renilla luciferase substrate, we could distinguish EV binding from uptake. We provide proof of concept of the system by analysing the effect of different chemical inhibitors, demonstrating that this method is highly sensitive and quantitative, allowing a dynamic follow-up in a high-throughput scheme to unravel the molecular mechanisms of EV uptake in different biological systems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biological Transport
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Extracellular Vesicles / metabolism*
  • Female
  • Genes, Reporter
  • Green Fluorescent Proteins / analysis
  • Green Fluorescent Proteins / genetics
  • High-Throughput Screening Assays / methods*
  • Humans
  • Imidazoles / metabolism
  • Luciferases, Renilla / analysis
  • Luciferases, Renilla / genetics
  • Luminescent Measurements
  • Nanoparticles
  • Pyrazines / metabolism
  • Recombinant Fusion Proteins / analysis
  • Recombinant Fusion Proteins / metabolism
  • Sensitivity and Specificity
  • Subcellular Fractions / chemistry
  • Tetraspanin 29 / genetics
  • Tetraspanin 29 / metabolism*
  • Tetraspanin 30 / genetics
  • Tetraspanin 30 / metabolism*

Substances

  • CD63 protein, human
  • CD9 protein, human
  • Imidazoles
  • Pyrazines
  • Recombinant Fusion Proteins
  • Tetraspanin 29
  • Tetraspanin 30
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • coelenterazine
  • Luciferases, Renilla