Genos Glycoscience Research Laboratory

Zagreb, Croatia

Genos Glycoscience Research Laboratory

Zagreb, Croatia
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PubMed | University of Edinburgh, Polyomica, Clinical Hospital Merkur, Allgemein und Viszeralchirurgie and 4 more.
Type: Journal Article | Journal: Clinical cancer research : an official journal of the American Association for Cancer Research | Year: 2016

Alternative glycosylation has significant structural and functional consequences on IgG and consequently also on cancer immunosurveillance. Because of technological limitations, the effects of highly heritable individual variations and the differences in the dynamics of changes in IgG glycosylation on colorectal cancer were never investigated before.Using recently developed high-throughput UPLC technology for IgG glycosylation analysis, we analyzed IgG glycome composition in 760 patients with colorectal cancer and 538 matching controls. Effects of surgery were evaluated in 28 patients sampled before and three times after surgery. A predictive model was built using regularized logistic regression and evaluated using a 10-cross validation procedure. Furthermore, IgG glycome composition was analyzed in 39 plasma samples collected before initial diagnosis of colorectal cancer.We have found that colorectal cancer associates with decrease in IgG galactosylation, IgG sialylation and increase in core-fucosylation of neutral glycans with concurrent decrease of core-fucosylation of sialylated glycans. Although a model based on age and sex did not show discriminative power (AUC = 0.499), the addition of glycan variables into the model considerably increased the discriminative power of the model (AUC = 0.755). However, none of these differences were significant in the small set of samples collected before the initial diagnosis.Considering the functional relevance of IgG glycosylation for both tumor immunosurveillance and clinical efficacy of therapy with mAbs, individual variation in IgG glycosylation may turn out to be important for prediction of disease course or the choice of therapy, thus warranting further, more detailed studies of IgG glycosylation in colorectal cancer. Clin Cancer Res; 22(12); 3078-86. 2016 AACR.


PubMed | Clinical Hospital Merkur, Genos Glycoscience Research Laboratory, Clinical and Experimental Pharmacokinetics Unit, SIMPAR Group Study in Multidisciplinary Pain Research and 2 more.
Type: | Journal: Scientific reports | Year: 2016

Systemic inflammation participates to the complex healing process occurring after major surgery, thus directly affecting the surgical outcome and patient recovery. Total plasma N-glycome might be an indicator of inflammation after major surgery, as well as an anti-inflammatory therapy response marker, since protein glycosylation plays an essential role in the inflammatory cascade. Therefore, we assessed the effects of surgery on the total plasma N-glycome and the association with self-administration of postoperative morphine in two cohorts of patients that underwent major abdominal surgery. We found that plasma N-glycome undergoes significant changes one day after surgery and intensifies one day later, thus indicating a systemic physiological response. In particular, we observed the increase of bisialylated biantennary glycan, A2G2S[3,6]2, 12hours after surgery, which progressively increased until 48 postoperative hours. Most changes occurred 24hours after surgery with the decrease of most core-fucosylated biantennary structures, as well as the increase in sialylated tetraantennary and FA3G3S[3,3,3]3 structures. Moreover, we observed a progressive increase of sialylated triantennary and tetraantennary structures two days after surgery, with a concomitant decrease of the structures containing bisecting N-acetylglucosamine along with bi- and trisialylated triantennary glycans. We did not find any statistically significant association between morphine consumption and plasma N-glycome.


Lauc G.,University of Zagreb | Lauc G.,Genos Glycoscience Research Laboratory | Pezer M.,Genos Glycoscience Research Laboratory | Rudan I.,University of Edinburgh | Campbell H.,University of Edinburgh
Biochimica et Biophysica Acta - General Subjects | Year: 2016

Background: The majority of human proteins are being modified by covalent attachment of complex oligosaccharides-glycans. Both glycans and polypeptide parts of a protein contribute to its structure and function, but contrary to polypeptide that is defined by the sequence of nucleotides in the corresponding gene, glycans are shaped by complex dynamic interactions between hundreds of enzymes, transcription factors, ion channels and other proteins. Scope of review: An overviewof current knowledge about the importance of N-glycans in normal human physiology and disease mechanisms, exemplified by IgG N-glycans. Major conclusions: Recent technological development enabled systematic analysis of glycome composition in large epidemiological cohorts and clinical studies. However, the majority of these studies is still missing any glycomic component, and consequently also lacks this layer of biological information. Individual variation in glycosylation is potentially important for individualized disease risk, disease course and response to therapy. Evidence in support of this hypothesis is accumulating, but further studies are needed to enable understanding of the role of changes in protein glycosylation in disease. General significance: Glycans are involved in virtually all physiological processes. Inter-individual variation in glycome composition is large, and these differences associate with disease risk, disease course and the response to therapy. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc. © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.


Trbojevic Akmacic I.,Genos Glycoscience Research Laboratory | Ventham N.T.,University of Edinburgh | Theodoratou E.,University of Edinburgh | Vuckovic F.,Genos Glycoscience Research Laboratory | And 15 more authors.
Inflammatory Bowel Diseases | Year: 2015

Glycobiology is an underexplored research area in inflammatory bowel disease (IBD), and glycans are relevant to many etiological mechanisms described in IBD. Alterations in N-glycans attached to the immunoglobulin G (IgG) Fc fragment can affect molecular structure and immunological function. Recent genome-wide association studies reveal pleiotropy between IBD and IgG glycosylation. This study aims to explore IgG glycan changes in ulcerative colitis (UC) and Crohn's disease (CD). Methods: IgG glycome composition in patients with UC (n= 507), CD (n= 287), and controls (n =320) was analyzed by ultra performance liquid chromatography. Results: Statistically significant differences in IgG glycome composition between patients with UC or CD, compared with controls, were observed. Both UC and CD were associated with significantly decreased IgG galactosylation (digalactosylation, UC: odds ratio [OR]= 0.71; 95% confidence interval [CI], 0.5-0.9; P= 0.01; CD: OR= 0.41; CI, 0.3-0.6; P= 1.4 × 10 -9) and significant decrease in the proportion of sialylated structures in CD (OR= 0.46, CI, 0.3-0.6, P= 8.4 × 10 -8). Logistic regression models incorporating measured IgG glycan traits were able to distinguish UC and CD from controls (UC: P= 2.13 × 10 -6 and CD: P =2.20 × 10 -16), with receiver-operator characteristic curves demonstrating better performance of the CD model (area under curve [AUC]= 0.77) over the UC model (AUC= 0.72) (P= 0.026). The ratio of the presence to absence of bisecting GlcNAc in monogalactosylated structures was increased in patients with UC undergoing colectomy compared with no colectomy (FDR-adjusted, P= 0.05). Conclusions: The observed differences indicate significantly increased inflammatory potential of IgG in IBD. Changes in IgG glycosylation may contribute to IBD pathogenesis and could alter monoclonal antibody therapeutic efficacy. IgG glycan profiles have translational potential as IBD biomarkers. © 2015 Crohn's and Colitis Foundation of America, Inc.


PubMed | University of Edinburgh, University of Zagreb and Genos Glycoscience Research Laboratory
Type: Journal Article | Journal: Biochimica et biophysica acta | Year: 2016

The majority of human proteins are being modified by covalent attachment of complex oligosaccharides--glycans. Both glycans and polypeptide parts of a protein contribute to its structure and function, but contrary to polypeptide that is defined by the sequence of nucleotides in the corresponding gene, glycans are shaped by complex dynamic interactions between hundreds of enzymes, transcription factors, ion channels and other proteins.An overview of current knowledge about the importance of N-glycans in normal human physiology and disease mechanisms, exemplified by IgG N-glycans.Recent technological development enabled systematic analysis of glycome composition in large epidemiological cohorts and clinical studies. However, the majority of these studies is still missing any glycomic component, and consequently also lacks this layer of biological information. Individual variation in glycosylation is potentially important for individualized disease risk, disease course and response to therapy. Evidence in support of this hypothesis is accumulating, but further studies are needed to enable understanding of the role of changes in protein glycosylation in disease.Glycans are involved in virtually all physiological processes. Inter-individual variation in glycome composition is large, and these differences associate with disease risk, disease course and the response to therapy. This article is part of a Special Issue entitled Glycans in personalised medicine Guest Editor: Professor Gordan Lauc.


PubMed | University of Zagreb and Genos Glycoscience Research Laboratory
Type: | Journal: Methods in enzymology | Year: 2017

Large-scale glycomics studies enable identification of aberrant glycosylation patterns in disease and provide information about functional relevance of individual glycans through genome-wide association studies. Developed high-throughput methodologies have to be sensitive, robust, and stable during long periods of time (few months) to be able to reliably detect small biological variations in glycosylation. Here, we describe a simple, robust, and affordable protocol for immunoglobulin G N-glycan analysis by hydrophilic interaction liquid chromatography-ultra-performance liquid chromatography (HILIC-UPLC), as well as useful strategies for method optimization: Plackett-Burman screening design and analysis of source of variation. We put our focus on experimental design for high-throughput glycan analysis, critical steps in sample preparation procedure for obtaining high-quality data, and propose a validation protocol relevant for high-throughput methods in terms of their long-term robustness and ability to detect biologically relevant changes in glycosylation. The quality of the procedure was assessed by employing appropriate experimental designs and subsequent statistical techniques.


PubMed | Leiden University, University of Zagreb and Genos Glycoscience Research Laboratory
Type: | Journal: Scientific reports | Year: 2016

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.

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