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Identification and characterization of TNFR1 exosome‐like vesicles in human plasma
Author(s) -
Zhang Jing,
Hawari Feras I,
Shamburek Robert D,
Adamik Barbara,
Kaler Maryann,
Levine Stewart J
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a112-c
Subject(s) - exosome , vesicle , microvesicles , chemistry , extracellular vesicle , biochemistry , microbiology and biotechnology , biology , membrane , microrna , gene
Extracellular TNFR1 (TNFRSF1A) is generated by two mechanisms, proteolytic cleavage of soluble TNFR1 ectodomains and release of full‐length TNFR1 exosome‐like vesicles. The goal of this study was to identify and characterize TNFR1 exosome‐like vesicles in human plasma. Western blots demonstrated a 48‐kDa TNFR1 in plasma from healthy volunteers. Fractionation by gel exclusion chromatography revealed that the 48‐kDa TNFR1 co‐segregated with LDL particles. TNFR1 exosome‐like vesicles in human serum were confirmed by immunoelectron microscopy. The 48‐kDa TNFR1 segregated independently from LDL particles by peak density (1.1 g/ml vs. 1.03 g/ml), which demonstrates that TNFR1 exosome‐like vesicles are distinct from LDL particles. ICAM‐1, LAMP‐1, and LAMP‐2, known exosome‐associated proteins, co‐segregated with the HDL fraction, which suggests that TNFR1 exosome‐like vesicles are distinct from typical exosomes. The reduced size of the 48‐kDa exosome‐associated TNFR1 reflected reduced N‐linked carbohydrate content. Thus, we propose human plasma contains TNFR1 exosome‐like vesicles that may regulate TNF‐mediated inflammatory events. This research is supported by DIR, NHLBI, NIH.