Label-free Proteomic Analysis of Exosomes Derived from Inducible Hepatitis B Virus-Replicating HepAD38 Cell Line
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ABSTRACT: Hepatitis B virus (HBV) infection is a major health problem worldwide. Recent evidence suggests that various viruses can manipulate the infection process by secretion of specific viral and cellular components into exosomes, small nanometer-sized (30-150 nm) vesicles secreted from various cells. However, the impact of HBV replication on hepatocytes produced exosomes has not been fully delineated. In this work, an HBV-inducible cell line HepAD38 was used to directly compare changes in the protein content of exosomes secreted from HepAD38 cells with or without HBV replication. Exosomes were isolated from conditioned medium of HepAD38 cell cultures and the purity of exosomes were confirmed by transmission electron microscopy (TEM) and Western immunoblotting assays. Ion-intensity based label-free LC−MS/MS quantitation technologies were applied to analyze protein content of HBV-exosomes and HBV-free-exosomes. A total of 1412 exosomal proteins were identified, in which the abundance of 35 proteins were significantly altered. Strikingly, 5 subunit proteins from the 26S proteasome complex, including PSMC1, PSMC2, PSMD1, PSMD7 and PSMD14 were consistently enhanced in HBV-exosomes. Bioinformatic analysis of differential exosomal proteins revealed the significant enrichment of components involved in proteasomal catabolic process. Proteasome activity assays further suggested that HBV-exosomes had enhanced proteolytic activity compared to HBV-free-exosomes. Furthermore, Human peripheral monocytes incubated with HBV-exosomes induced a significant lower level of IL-6 secretion compared to HBV-free-exosomes. Irreversible inhibition of proteasomal activity within exosome restored the IL-6 induction in monocytes. These results suggest that transmission of proteasome subunit proteins by HBV-exosomes might modulate the innate sensing of pro-inflammatory molecules in the recipient monocytes. These results revealed the composition and potential function of exosomes produced during HBV replication, thus provide a new perspective on the role of exosomes in HBV-host interaction.
INSTRUMENT(S): Q Exactive
ORGANISM(S): Homo Sapiens (human)
TISSUE(S): Cell Culture
SUBMITTER: Xiaofang Jia
LAB HEAD: Zhenghong Yuan
PROVIDER: PXD004724 | Pride | 2017-03-01
REPOSITORIES: Pride
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