ANCA-associated vasculitis.

The anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) are a group of disorders involving severe, systemic, small-vessel vasculitis and are characterized by the development of autoantibodies to the neutrophil proteins leukocyte proteinase 3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA). The three AAV subgroups, namely granulomatosis with polyangiitis (GPA), microscopic polyangiitis and eosinophilic GPA (EGPA), are defined according to clinical features. However, genetic and other clinical findings suggest that these clinical syndromes may be better classified as PR3-positive AAV (PR3-AAV), MPO-positive AAV (MPO-AAV) and, for EGPA, by the presence or absence of ANCA (ANCA+ or ANCA-, respectively). Although any tissue can be involved in AAV, the upper and lower respiratory tract and kidneys are most commonly and severely affected. AAVs have a complex and unique pathogenesis, with evidence for a loss of tolerance to neutrophil proteins, which leads to ANCA-mediated neutrophil activation, recruitment and injury, with effector T cells also involved. Without therapy, prognosis is poor but treatments, typically immunosuppressants, have improved survival, albeit with considerable morbidity from glucocorticoids and other immunosuppressive medications. Current challenges include improving the measures of disease activity and risk of relapse, uncertainty about optimal therapy duration and a need for targeted therapies with fewer adverse effects. Meeting these challenges requires a more detailed knowledge of the fundamental biology of AAV as well as cooperative international research and clinical trials with meaningful input from patients

Plasma N-Glycome Signature of Down Syndrome

In recent years, plasma N-glycans have emerged as biomarkers for health and disease. Here, we studied N-glycomic changes in Down Syndrome (DS). Because of the progeroid phenotype of DS, we focused on the dissection of syndrome- and aging-associated glycomic changes, as well as the interaction thereof. We analyzed the plasma N-glycome of 76 DS persons, 37 siblings (DSS), and 42 mothers (DSM) of DS persons by DNA-sequencer-aided, fluorophore-assisted-carbohydrate-electrophoresis, as well as by matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS). The results showed an overall decrease of galactosylation and α2,3 sialylation, a concomitant increase of the level of fucosylated N-glycans as well as of monogalactosylated diantennary N-glycans in DS, while the GlycoAgeTest and the ratio of the two core-fucosylated, monogalactosylated diantennary isomers (galactose positioned on α1,6 arm versus α1,3 arm) were the strongest DS discriminators. Hypogalactosylation is a characteristic of both DS and aging of control individuals. A decrease in α2,3-sialylated species is also common to DS and aging of controls. However, regarding to α2,6-sialylated tri- and tetragalactosylated N-glycan species, we found those to be lowered in DS but showed an increase with age in the same persons, while these glycans were not affected by aging in control individuals. In conclusion, we identified specific glycomic changes associated with DS, aging in DS, as well as aging in controls, identifying glycomic features in line with accelerated aging in DS. Notably, our data demonstrate an aging phenotype in DS which only in part overlaps with aging in controls but reveals DS-specificity

Immunoglobulin A glycosylation differs between Crohn's disease and ulcerative colitis

Inflammatory bowel diseases (IBD), such as Crohn’s disease (CD) and ulcerative colitis (UC), are chronic and relapsing inflammations of the digestive tract with increasing prevalence, yet they have unknown origins or cure. CD and UC have similar symptoms but respond differently to surgery and medication. Current diagnostic tools often involve invasive procedures, while laboratory markers for patient stratification are lacking. Large glycomic studies of immunoglobulin G and total plasma glycosylation have shown biomarker potential in IBD and could help determine disease mechanisms and therapeutic treatment choice. Hitherto, the glycosylation signatures of plasma immunoglobulin A, an important immunoglobulin secreted into the intestinal mucin, have remained undetermined in the context of IBD. Our study investigated the associations of immunoglobulin A1 and A2 glycosylation with IBD in 442 IBD cases (188 CD and 254 UC) and 120 healthy controls by reversed-phase liquid chromatography electrospray-ionization mass spectrometry of tryptic glycopeptides. Differences of IgA O- and N-glycosylation (including galactosylation, bisection, sialylation, and antennarity) between patient groups were associated with the diseases, and these findings led to the construction of a statistical model to predict the disease group of the patients without the need of invasive procedures. This study expands the current knowledge about CD and UC and could help in the development of noninvasive biomarkers and better patient care. Proteomic

Plasma protein N-glycan signatures of type 2 diabetes

Proteomic

DNA hypomethylation upregulates expression of the MGAT3 gene in HepG2 cells and leads to changes in N-glycosylation of secreted glycoproteins

Changes in N-glycosylation of plasma proteins are observed in many types of cancer, nevertheless, few studies suggest the exact mechanism involved in aberrant protein glycosylation. Here we studied the impact of DNA methylation on the N-glycome in the secretome of the HepG2 cell line derived from hepatocellular carcinoma (HCC). Since the majority of plasma glycoproteins originate from the liver, the HepG2 cells represent a good model for glycosylation changes in HCC that are detectable in blood, which is an easily accessible analytic material in a clinical setting. Two different concentrations of 5-aza-2'- deoxycytidine (5-aza-2dC) differentially affected global genome methylation and induced different glycan changes. Around twenty percent of 84 glyco-genes analysed changed expression level after the 5-aza-2dC treatment as a result of global genome hypomethylation. A correlation study between the changes in glyco-gene expression and the HepG2 glycosylation profile suggests that the MGAT3 gene might be responsible for the glycan changes consistently induced by both doses of 5-aza-2dC. Core-fucosylated tetra-antennary structures were decreased in quantity likely as a result of hypomethylated MGAT3 gene promoter followed by increased expression of this gene.Proteomic

Plasma N-Glycan Signatures Are Associated With Features of Inflammatory Bowel Diseases

Proteomic

Glycoproteomics Technologies in Glycobiotechnology

Glycosylation is a key factor determining the pharmacological properties of biotherapeutics, including their stability, solubility, bioavailability, pharmacokinetics, and immunogenicity. As such, comprehensive information about glycosylation of biotherapeutics is critical to demonstrate similarity. Regulatory agencies also require extensive documentation of the comprehensive analyses of glycosylation-related critical quality attributes (CQAs) during the development, manufacturing, and release of biosimilars. Mass spectrometry has catalysed tremendous advancements in the characterisation of glycosylation CQAs of biotherapeutics. Here we provide a perspective overview on the MS-based technologies relevant for biotherapeutic product characterisation with an emphasis on the recent developments that allow determination of glycosylation features such as site of glycosylation, sialic acid linkage, glycan structure, and content.Graphical AbstractOpen image in new windo