IgG purification- MS analysis - MS analysis was undertaken on human IgG purified using different approaches to assess purifity and potential alterations within the IgG N-linked glycans
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Fusion Lumos, LTQ Orbitrap Elite
ORGANISM(S): Homo Sapiens (human)
SUBMITTER: 
Nichollas Scott
LAB HEAD: Amy Chung
PROVIDER: PXD014235 | Pride | 2019-11-01
REPOSITORIES: Pride
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Project description:Immunoglobulin G (IgG) molecules modulate an immune response. However, site-specific N-glycosylation signatures of plasma IgG in patients with chronic kidney disease (CKD) remain unclear. This study aimed to propose a novel method to explore the N-glycosylation pattern of IgG and to compare it with reported methods. We separated human plasma IgG from 58 healthy controls (HC) and 111 patients with CKD. Purified IgG molecules were digested by trypsin. Tryptic peptides with-out enrichment were analyzed using a combination of electron-transfer/higher-energy collisional dissociation (EThcD) and stepped collision energy/higher-energy collisional dissociation (sceHCD) mass spectrometry (EThcD-sceHCD-MS/MS). This resulted in higher spectral quality, more informative fragment ions, higher Byonic score, and nearly twice the depth of intact N-glycopeptide identification than sceHCD or EThcD alone. Site-specific N-glycosylation mapping revealed that intact N-glycopeptides were differentially expressed in HC and CKD patients; thus, it can be a diagnostic tool. This study provides a method for the determination of glycosylation patterns in CKD and a framework for understanding the role of IgG in the pathophysiology of CKD.
2021-11-25 | PXD027174 | Pride
Project description:Changes in IgG glycosylation have been reported to be associated with colorectal cancer (CRC), but the alteration in specific subclass of IgG is unknown. Herein, we optimized five common IgG glycopeptides enrichment methods to acquire comprehensive profiling of IgG glycoproteomics in CRC. Notably, incomplete tryptic digestion of IgG occurred when using ordinary ratio of protease to protein, which significantly impacted the final statistical analysis of association between IgG glycosylation and CRC. We introduced a method based on two-step enzymatic digestion, enabling the complete digestion of IgG glycopeptides and further improving the detection intensity of the target glycopeptides. By this approach, total 47 IgG glycopeptides can be identified by nanoLC-ESI-MS/MS. Following rapid and automatic data processing through the self-developed program, we observed that IgG1_H3N4F1 and IgG1_H3N4 were substantially increased in CRC, while IgG1_H5N5F1, IgG1_H5N4F1S1and IgG2_H5N4F1 were markedly decreased. Strikingly, these four glycopeptides were continually significantly changed in early and late stages of CRC. Further evaluation of the diagnostic performance showed they all obtained a fair performance in discriminating the patients from the normal. In terms of the glycan features, it demonstrated that CRC progression associates with the increased agalactosylation, and the decreased digalactosylation and galactosylation per antenna on diantennay glycans of IgG1 and IgG2. Concurrently, the decreased sialylation of IgG1 was strongly correlated with CRC. Moreover, tumor-specific glycosylation analysis showed that the alterations of subclass-specific IgG glycosylation were more significant in colon cancer, and no obvious difference between colon and rectal cancer was found. More importantly, all these findings were validated in an independent cohort. This two-step enzymatic approach is crucial to explore the relationship between the disease progression and IgG glycosylation.
2022-10-27 | PXD016318 | Pride
Project description:<p><strong>BACKGROUND:</strong> Novel biomarkers are urgently needed to distinguish between benign and malignant thyroid nodules and detect thyroid cancer in the early stage. The associations between serum IgG N-glycosylation and thyroid cancer risk have been revealed. We aimed to explore the potential of IgG N-glycan traits as biomarkers in the differential diagnosis of thyroid cancer.</p><p><strong>METHODS:</strong> Plasma IgG N-glycome analysis was applied to a discovery cohort followed by independent validation. IgG N-glycan profiles were obtained using a robust quantitative strategy based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. IgG N-glycans were relatively quantified, and classification performance was evaluated based on directly detected and derived glycan traits.</p><p><strong>RESULTS: </strong>Four directly detected glycans were significantly changed in thyroid cancer patients compared to that in non-cancer controls. Derived glycan traits and a classification glycol-panel were generated based on the directly detected glycan traits. In the discovery cohort, derived trait BN (bisecting type neutral N-glycans) and the glyco-panel showed potential in distinguishing between thyroid cancer and non-cancer controls with AUCs of 0.920 and 0.917, respectively. The diagnostic potential was further validated. Derived trait BN and the glycol-panel displayed “accurate” performance (AUC>0.8) in discriminating thyroid cancer from benign thyroid nodules and healthy controls in the validation cohort. Meanwhile, derived trait BN and the glycol-panel also showed diagnostic potential in detecting early-stage thyroid cancer.</p><p><strong>CONCLUSIONS:</strong> IgG N-glycome analysis revealed N-glycomic differences that allow classification of thyroid cancer from non-cancer controls. Our results suggested that derived trait BN and the classification glyco-panel rather than single N-glycans may serve as candidate biomarkers for further validation.</p>
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2022-08-30 | PXD035846 | Pride
Project description:NOTCH1 (N1) is a transmembrane receptor that initiates a cell-cell signaling pathway controlling various cell fate specifications in metazoans. The addition of O-fucose by Protein O-fucosyltransferase 1 (POFUT1) to Epidermal Growth Factor-like (EGF) repeats in the N1 extracellular domain is essential for N1 function, and modification of O-fucose with GlcNAc by the Fringe family of glycosyltransferases modulates Notch activity. Prior cell-based studies showed that POFUT1 modifies EGF repeats containing the appropriate consensus sequence at high stoichiometry, while Fringe GlcNAc-transferases (LFNG, MFNG and RFNG) modify O-fucose on only a subset of NOTCH1 EGF repeats. Previous in vivo studies showed that each FNG affects naïve T cell development. To examine Fringe modifications of N1 expressed at a physiological level, we used mass spectral glycoproteomic methods to analyze O-fucose glycans of endogenous N1 from activated T cells obtained from mice lacking all Fringe enzymes, or expressing only a single FNG. While most O-fucose sites were modified at high stoichiometry, only EGF6, EGF16, EGF26, and EGF27 were extended in control T cells. Cell-based assays of N1 lacking fucose at each of those O-fucose sites revealed minor functional correlations in the EGF16 and EGF27 mutant with Notch ligand binding. In activated T cells expressing only LFNG, MFNG or RFNG alone, the extension of O-fucose with GlcNAc in the same EGF repeats was diminished, consistent with cooperative interactions when all three Fringes were present. The combined data open the door for the analysis of O-glycans on endogenous N1 derived from different cell types.
2022-08-12 | PXD031297 | Pride
Project description:Maternal IgG is an immunoglobulin present in breast milk and has been shown to play a role in the development of the immune system in infants. The aim of this study was to investigate the effects of maternal IgG on brain development in mouse pups. Maternal IgG immunoreactivity was observed in microglial cells of the pup brain, peaking at postnatal 8 day. In particular, strong IgG immunoreactivity was observed in the microglia in the corpus callosum and cerebellar white matter. IgG stimulation of primary cultured microglia resulted in activation of the type I interferon feedback loop by Syk. Among the IgG subclasses, IgG2a was found to have a strong influence on microglia. Analysis of FcRn KO mice that were unable to take up IgG from their mothers revealed that these mice had abnormalities in the proliferation and/or survival of microglia, oligodendrocytes, and some types of interneurons. FcRn KO mice also exhibited abnormalities in social behavior and adaptation to novel environments. This study suggests that maternal IgG affects brain development in pups.
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Project description:Saliva based diagnostics is a rapidly evolving field due to the large potential of saliva and the simple sample collection. A systematic comparison of IgG antibody profiles in saliva and plasma is currently lacking in scientific literature. Our hypothesis is that IgG profiles are equal in blood and saliva. By showing the equality of the profiles and relative IgG antigenic reactivities towards proteins and peptides we provide evidence that plasma IgG reactivities can be inferred from saliva IgG reactivities. IgG antibodies were isolated from human saliva and plasma samples. The reactivities of IgG isolates were analysed on peptide microarrays displaying linear epitopes of EBV (EBNA1 protein) and HBV (Large envelope protein) virus. Peptide arrays were printed by JPT Peptide Technologies (Berlin, Germany). We show high similarity of saliva and plasma IgG profiles on these two platforms and argue for generalisation from this subset to the whole immunological IgG antibody profile.
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Project description:Saliva based diagnostics is a rapidly evolving field due to the large potential of saliva and the simple sample collection. A systematic comparison of IgG antibody profiles in saliva and plasma is currently lacking in scientific literature. Our hypothesis is that IgG profiles are equal in blood and saliva. By showing the equality of the profiles and relative IgG antigenic reactivities towards proteins and peptides we provide evidence that plasma IgG reactivities can be inferred from saliva IgG reactivities. IgG antibodies were isolated from human saliva and plasma samples. The reactivities of IgG isolates were analysed on peptide microarrays displaying linear epitopes of EBV (EBNA1 protein) and HBV (Large envelope protein) virus. Peptide arrays were printed by JPT Peptide Technologies (Berlin, Germany). We show high similarity of saliva and plasma IgG profiles on these two platforms and argue for generalisation from this subset to the whole immunological IgG antibody profile.
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