Label-Free Proteomic Analysis of Exosomes Secreted from THP-1-Derived Macrophages Treated with IFN‑α Identifies Antiviral Proteins Enriched in Exosomes

Exosomes are extracellular vesicles
that function in intercellular
communication. We have previously reported that exosomes play an important
role in the transmission of antiviral molecules during interferon-α
(IFN-α) treatment. In this study, the protein profiles of THP-1-derived
macrophages with or without interferon-α treatment and the exosomes
secreted from these cells were analyzed by label-free liquid chromatography–tandem
mass spectrometry quantitation technologies. A total of 1845 and 1550
protein groups were identified in the THP-1 macrophages and the corresponding
exosomes, respectively. Treating the cells with IFN-α resulted
in the differential abundance of 94 proteins in cells and 67 proteins
in exosomes (greater than 2.0-fold), among which 23 proteins were
up-regulated in both the IFN-α treated cells and corresponding
exosomes, while 14 proteins were specifically up-regulated in exosomes
but not in the donor cells. GO and KEGG analysis of the identified
proteins suggested that IFN-α promoted the abundance of proteins
involved in the “defense response to virus” and “type
I interferon signaling pathway” in both exosomes and cells.
Functional analysis further indicated that exosomes from IFN-α-treated
cells exhibited potent antiviral activity that restored the impaired
antiviral response of IFN-α in hepatitis B virus-replicating
hepatocytes. These results have deepened the understanding of the
exosome-mediated transfer of IFN-α-induced antiviral molecules
and may provide a new basis for therapeutic strategies to control
viral infection.