Proteomic profiling of human plasma exosomes identifies PPARgamma as an exosome-associated protein.
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.
Looze
Christopher
C
Pulmonary and Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Building, Room 6D03, MSC 1590, Bethesda, MD 20892, USA.
Yui
David
D
Leung
Lester
L
Ingham
Matthew
M
Kaler
Maryann
M
Yao
Xianglan
X
Wu
Wells W
WW
Shen
Rong-Fong
RF
Daniels
Mathew P
MP
Levine
Stewart J
SJ
D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D055354:Exosomes / Q000378:metabolism*; D006801:Humans; D053419:Lipoproteins, IDL / Q000097:blood; D008079:Lipoproteins, VLDL / Q000097:blood; D013058:Mass Spectrometry; D047495:PPAR gamma / Q000097:blood*; D040081:Protein Array Analysis; D040901:Proteomics; D044967:Serum / Q000378:metabolism*
D053419:Lipoproteins, IDL; D008079:Lipoproteins, VLDL; D047495:PPAR gamma