Platelet Factor 4 as a Novel Exosome Marker in MALDI-MS Analysis of Exosomes from Human Serum

Huu Quang Nguyen, Dabin Lee, Yeoseon Kim, Minseok Paek, Minsun Kim, Kyoung Soon Jang, Jooyeon Oh, Young Sun Lee, Jong Eun Yeon, David M. Lubman, Jeongkwon Kim

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41 Citations (Scopus)


Exosomes are nanosized vesicles commonly found in biological fluids as a result of a secretion process involving endosomes and multivesicular bodies. The isolation and analysis of exosomes can be useful for noninvasive clinical diagnosis of a variety of human diseases. We investigated the utility of analyzing exosomal proteins, using matrix-assisted laser desorption/ionization combined with Fourier-transform ion cyclotron resonance mass spectrometry (MALDI-FTICR-MS), as a means of determining the presence of exosomes. MALDI-FTICR-MS analyses of exosomes enriched from human serum via centrifugation in a mass range of m/z 1000-20 000 yielded a distinctive protein around m/z 7766. The high mass accuracy and resolution of MALDI-FTICR-MS allowed for reliable comparisons against a protein database, through which the protein was identified as platelet factor 4 (PLF4), whose singly charged protein peak has an elemental composition of C341H577N96O101S4 +, with a theoretical most abundant isotopic peak at m/z 7765.194 and a theoretical average peak at m/z 7766. The MALDI-TOF MS analysis of exosomes from the serum of 27 patients with different states of liver diseases provided the most abundant PLF4 peak for each mass spectrum, along with several additional minor peaks. In conclusion, MALDI-MS is suitable as an alternative exosome detection method, serving as a valuable confirmation tool, greatly decreasing the time and workload associated with exosome identification.

Original languageEnglish
Pages (from-to)13297-13305
Number of pages9
JournalAnalytical chemistry
Issue number20
Publication statusPublished - 2019 Oct 15

Bibliographical note

Publisher Copyright:
Copyright © 2019 American Chemical Society.

ASJC Scopus subject areas

  • Analytical Chemistry


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