Proteomic analyses of plasma-derived exosomes in IgG4-RD and its potential role in B cell differentiation and tissue damage

ABSTRACT: Objective: This study aimed to investigate plasma exosome profiling of IgG4-RD and its potential role in B cell differentiation and tissue damage. Methods: One hundred untreated IgG4-RD patients and 135 sex, age matched healthy controls (HCs) were enrolled in this study. A combination of liquid chromatography-tandem mass spectroscopy (LC-MS/MS) and TMT label quantitation was used to detect exosome and B cell profiling. To validate differentially expressed proteins, western blot and ELISA were performed. RT-qPCR was used to detect gene expression after exosome stimulation. Flowcytometry was used to measure B cell activation, apoptosis, differentiation and reactive oxygen species (ROS) expression. Besides, correlation analysis between differentially expressed complement protein and laboratory parameters was also performed. Results: In total, 82 proteins were upregulated and 96 proteins were downregulated in exosome of IgG4-RD patients compared with HCs. Pathway analysis revealed that complement cascade pathway in exosome of IgG4-RD was activated, together with reduced C3 complement and C5 complement. Validation by ELISA and WB, exosome C3 and C5 was decrease in IgG4-RD compared with HCs. Stimulation of B cells with exosome, naïve B cells decreased, while memory B cells and plasmablast were increased together with increased CYCS with activation of downstream complement system. ROS was increased in B cells of IgG4-RD compared with HC. In affected submandibular glands, BCR signaling pathway was activated and exosome may potentially participate in tissue damage. Conclusion: There were 82 differentially expressed upregulated proteins and 96 downregulated proteins in IgG4-RD exosome compared with HCs. Differentially expressed proteins were enriched in exosome, complement function and immune response indicating complement activation in exosome may be related to IgG4-RD. Reduced C3 and C5 expression in exosome of IgG4-RD may indicate the disease severity. Our research suggests that IgG4-RD exosomes can participate in the differentiation B cells into plasmablast, activate the B cell auto-oxidative damage pathway and potentially participate in the pathogenesis of IgG4-RD.

ORGANISM(S): Homo Sapiens

SUBMITTER: Wei Ge  

PROVIDER: PXD021441 | iProX | Mon Sep 14 00:00:00 BST 2020

REPOSITORIES: iProX