Proteomic profiling of human plasma exosomes identifies PPARgamma as an exosome-associated protein

Biochem Biophys Res Commun. 2009 Jan 16;378(3):433-8. doi: 10.1016/j.bbrc.2008.11.050. Epub 2008 Nov 24.


Exosomes are nanovesicles that are released from cells as a mechanism of cell-free intercellular communication. Only a limited number of proteins have been identified from the plasma exosome proteome. Here, we developed a multi-step fractionation scheme incorporating gel exclusion chromatography, rate zonal centrifugation through continuous sucrose gradients, and high-speed centrifugation to purify exosomes from human plasma. Exosome-associated proteins were separated by SDS-PAGE and 66 proteins were identified by LC-MS/MS, which included both cellular and extracellular proteins. Furthermore, we identified and characterized peroxisome proliferator-activated receptor-gamma (PPARgamma), a nuclear receptor that regulates adipocyte differentiation and proliferation, as well as immune and inflammatory cell functions, as a novel component of plasma-derived exosomes. Given the important role of exosomes as intercellular messengers, the discovery of PPARgamma as a component of human plasma exosomes identifies a potential new pathway for the paracrine transfer of nuclear receptors.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Chromatography, Liquid
  • Electrophoresis, Polyacrylamide Gel
  • Exosomes / metabolism*
  • Humans
  • Lipoproteins, IDL / blood
  • Lipoproteins, VLDL / blood
  • Mass Spectrometry
  • PPAR gamma / blood*
  • Protein Array Analysis
  • Proteomics*
  • Serum / metabolism*


  • Lipoproteins, IDL
  • Lipoproteins, VLDL
  • PPAR gamma