N-glycopeptide Signatures of IgA2 in Serum from Patients with Hepatitis B Virus-related Liver Diseases

• Published in: Molecular & cellular proteomics 2019-11, Vol.18 (11), p.2262-2272
• Main Authors: Zhang, Shu, Cao, Xinyi, Liu, Chao, Li, Wei, Zeng, Wenfeng, Li, Baiwen, Chi, Hao, Liu, Mingqi, Qin, Xue, Tang, Lingyi, Yan, Guoquan, Ge, Zefan, Liu, Yinkun, Gao, Qiang, Lu, Haojie
• Format: Article
• Language: English
• Subjects: 40-kDa Band; Biomarker: Diagnostic; Glycomics; Glycopeptide; Glycoproteomics; HBV-Related Liver Diseases; IgA2; Liver Disease; Mass Spectremetry; Mass Spectrometry
• ISSN: 1535-9476; 1535-9484
• DOI: 10.1074/mcp.RA119.001722

18O/16O labeling N-glycopeptide quantification and MRM have been performed to investigate aberrant N-glycopeptides in HBV-related liver diseases. TPLTAN205ITK (H5N5S1F1) and (H5N4S2F1) of IgA2 were significantly elevated in serum from patients with HBV infection and even higher in LC, as compared with healthy donor. In contrast, the two glycopeptides of IgA2 fell back down in HBV-related HCC. The altered N-glycopeptides might be part of a unique glycan signature indicating IgA-mediated mechanism. [Display omitted] Highlights •18O/16O labeling N-glycopeptide quantification for 40-kDa band in HCC and LC.•MRM verification of aberrant N-glycopeptides in healthy-HBV-LC-HCC cascade.•TPLTAN205ITK (H5N5S1F1) and (H5N4S2F1) of IgA2 change in liver diseases.•Variation in two N-glycopeptides abundance not caused by protein concentration. N-glycosylation alteration has been reported in liver diseases. Characterizing N-glycopeptides that correspond to N-glycan structure with specific site information enables better understanding of the molecular pathogenesis of liver damage and cancer. Here, unbiased quantification of N-glycopeptides of a cluster of serum glycoproteins with 40–55 kDa molecular weight (40-kDa band) was investigated in hepatitis B virus (HBV)-related liver diseases. We used an N-glycopeptide method based on 18O/16O C-terminal labeling to obtain 82 comparisons of serum from patients with HBV-related hepatocellular carcinoma (HCC) and liver cirrhosis (LC). Then, multiple reaction monitoring (MRM) was performed to quantify N-glycopeptide relative to the protein content, especially in the healthy donor-HBV-LC-HCC cascade. TPLTAN205ITK (H5N5S1F1) and (H5N4S2F1) corresponding to the glycopeptides of IgA2 were significantly elevated in serum from patients with HBV infection and even higher in HBV-related LC patients, as compared with healthy donor. In contrast, the two glycopeptides of IgA2 fell back down in HBV-related HCC patients. In addition, the variation in the abundance of two glycopeptides was not caused by its protein concentration. The altered N-glycopeptides might be part of a unique glycan signature indicating an IgA-mediated mechanism and providing potential diagnostic clues in HBV-related liver diseases.