| 1. |
- Birukov, Anna, et al.
(författare)
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Immunoglobulin G N-Glycosylation Signatures in Incident Type 2 Diabetes and Cardiovascular Disease
- 2022
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Ingår i: Diabetes Care. - : American Diabetes Association. - 1935-5548 .- 0149-5992. ; 45:11, s. 2729-2736
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE N-glycosylation is a functional posttranslational modification of immunoglobulins (Igs). We hypothesized that specific IgG N-glycans are associated with incident type 2 diabetes and cardiovascular disease (CVD). RESEARCH DESIGN AND METHODS We performed case-cohort studies within the population-based European Prospective Investigation into Cancer and Nutrition (EPIC)–Potsdam cohort (2,127 in the type 2 diabetes subcohort [741 incident cases]; 2,175 in the CVD subcohort [417 myocardial infarction and stroke cases]). Relative abundances of 24 IgG N-glycan peaks (IgG-GPs) were measured by ultraperformance liquid chromatog-raphy, and eight glycosylation traits were derived based on structural similarity. End point–associated IgG-GPs were preselected with fractional polynomials, and prospective associations were estimated in confounder-adjusted Cox models. Diabetes risk associations were validated in three independent studies. RESULTS After adjustment for confounders and multiple testing correction, IgG-GP7, IgG-GP8, IgG-GP9, IgG-GP11, and IgG-GP19 were associated with type 2 diabetes risk. A score based on these IgG-GPs was associated with a higher diabetes risk in EPIC-Potsdam and independent validation studies (843 total cases, 3,149 total non-cases, pooled estimate per SD increase 1.50 [95% CI 1.37–1.64]). Associations of IgG-GPs with CVD risk differed between men and women. In women, IgG-GP9 was inversely associated with CVD risk (hazard ratio [HR] per SD 0.80 [95% CI 0.65–0.98]). In men, a weighted score based on IgG-GP19 and IgG-GP23 was associated with higher CVD risk (HR per SD 1.47 [95% CI 1.20–1.80]). In addition, several derived traits were associated with cardiometabolic disease incidence. CONCLUSIONS Selected IgG N-glycans are associated with cardiometabolic risk beyond classic risk factors, including clinical biomarkers.
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| 2. |
- Frkatović-Hodžić, Azra, et al.
(författare)
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Mapping of the gene network that regulates glycan clock of ageing
- 2023
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Ingår i: Aging. - 1945-4589. ; 15:24, s. 14509-14552
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Tidskriftsartikel (refereegranskat)abstract
- Glycans are an essential structural component of immunoglobulin G (IgG) that modulate its structure and function. However, regulatory mechanisms behind this complex posttranslational modification are not well known. Previous genome-wide association studies (GWAS) identified 29 genomic regions involved in regulation of IgG glycosylation, but only a few were functionally validated. One of the key functional features of IgG glycosylation is the addition of galactose (galactosylation), a trait which was shown to be associated with ageing. We performed GWAS of IgG galactosylation (N=13,705) and identified 16 significantly associated loci, indicating that IgG galactosylation is regulated by a complex network of genes that extends beyond the galactosyltransferase enzyme that adds galactose to IgG glycans. Gene prioritization identified 37 candidate genes. Using a recently developed CRISPR/dCas9 system we manipulated gene expression of candidate genes in the in vitro IgG expression system. Upregulation of three genes, EEF1A1, MANBA and TNFRSF13B, changed the IgG glycome composition, which confirmed that these three genes are involved in IgG galactosylation in this in vitro expression system.
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| 3. |
- Huffman, Jennifer E., et al.
(författare)
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Polymorphisms in B3GAT1, SLC9A9 and MGAT5 are associated with variation within the human plasma N-glycome of 3533 European adults
- 2011
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 20:24, s. 5000-5011
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Tidskriftsartikel (refereegranskat)abstract
- The majority of human proteins are post-translationally modified by covalent addition of one or more complex oligosaccharides (glycans). Alterations in glycosylation processing are associated with numerous diseases and glycans are attracting increasing attention both as disease biomarkers and as targets for novel therapeutic approaches. Using a recently developed high-throughput high-performance liquid chromatography (HPLC) analysis method, we have reported, in a pilot genome-wide association study of 13 glycan features in 2705 individuals from three European populations, that polymorphisms at three loci (FUT8, FUT6/FUT3 and HNF1A) affect plasma levels of N-glycans. Here, we extended the analysis to 33 directly measured and 13 derived glycosylation traits in 3533 individuals and identified three novel gene association (MGAT5, B3GAT1 and SLC9A9) as well as replicated the previous findings using an additional European cohort. MGAT5 (meta-analysis association P-value = 1.80 x 10(-10) for rs1257220) encodes a glycosyltransferase which is known to synthesize the associated glycans. In contrast, neither B3GAT1 (rs7928758, P = 1.66 x 10(-08)) nor SLC9A9 (rs4839604, P = 3.50 x 10(-13)) had previously been associated functionally with glycosylation of plasma proteins. Given the glucuronyl transferase activity of B3GAT1, we were able to show that glucuronic acid is present on antennae of plasma glycoproteins underlying the corresponding HPLC peak. SLC9A9 encodes a proton pump which affects pH in the endosomal compartment and it was recently reported that changes in Golgi pH can impair protein sialylation, giving a possible mechanism for the observed association.
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| 4. |
- Igl, Wilmar, et al.
(författare)
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Glycomics meets lipidomics-associations of N-glycans with classical lipids, glycerophospholipids, and sphingolipids in three European populations
- 2011
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Ingår i: Molecular BioSystems. - : Royal Society of Chemistry (RSC). - 1742-206X .- 1742-2051. ; 7:6, s. 1852-1862
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Tidskriftsartikel (refereegranskat)abstract
- Recently, high-throughput technologies have been made available which allow the measurement of a broad spectrum of glycomics and lipidomics parameters in many samples. The aim of this study was to apply these methods and investigate associations between 46 glycan and 183 lipid traits measured in blood of 2041 Europeans from three different local populations (Croatia - VIS cohort; Sweden - NSPHS cohort; Great Britain - ORCADES cohort). N-glycans have been analyzed with High Performance Liquid Chromatography (HPLC) and lipids with Electrospray Ionization Tandem Mass Spectrometry (ESI-MS/MS) covering sterol lipids, glycerolipids, glycerophospholipids and sphingolipids in eight subclasses. Overall, 8418 associations were calculated using linear mixed effect models adjusted for pedigree, sex, age and multiple testing. We found 330 significant correlations in VIS. Pearson's correlation coefficient r ranged from -0.27 to 0.34 with corresponding p-values between 1.45 x 10(-19) and 4.83 x 10(-6), indicating statistical significance. A total of 71 correlations in VIS could be replicated in NSPHS (r = [-0.19; 0.35], p = [4.16 x 10(-18); 9.38 x 10(-5)]) and 31 correlations in VIS were also found in ORCADES (r = [-0.20; 0.24], p = [2.69 x 10(-10); 7.55 x 10(-5)]). However, in total only 10 correlations between a subset of triantennary glycans and unsaturated phosphatidylcholine, saturated ceramide, and sphingomyelin lipids in VIS (r = [0.18; 0.34], p = [2.98 x 10(-21); 1.69 x 10(-06)]) could be replicated in both NSPHS and ORCADES. In summary, the results show strong and consistent associations between certain glycans and lipids in all populations, but also population-specific correlations which may be caused by environmental and genetic differences. These associations point towards potential interactive metabolic pathways.
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| 5. |
- Johansson, Åsa, et al.
(författare)
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Linkage and genome-wide association analysis of obesity-related phenotypes : association of weight with the MGAT1 gene
- 2010
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Ingår i: Obesity. - : Wiley. - 1930-7381 .- 1930-739X. ; 18:4, s. 803-808
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Tidskriftsartikel (refereegranskat)abstract
- As major risk-factors for diabetes and cardiovascular diseases, the genetic contribution to obesity-related traits has been of interest for decades. Recently, a limited number of common genetic variants, which have replicated in different populations, have been identified. One approach to increase the statistical power in genetic mapping studies is to focus on populations with increased levels of linkage disequilibrium (LD) and reduced genetic diversity. We have performed joint linkage and genome-wide association analyses for weight and BMI in 3,448 (linkage) and 3,925 (association) partly overlapping healthy individuals from five European populations. A total of four chromosomal regions (two for weight and two for BMI) showed suggestive linkage (lod >2.69) either in one of the populations or in the joint data. At the genome-wide level (nominal P < 1.6 × 10−7, Bonferroni-adjusted P < 0.05) one single-nucleotide polymorphism (SNP) (rs12517906) (nominal P = 7.3 × 10−8) was associated with weight, whereas none with BMI. The SNP associated with weight is located close to MGAT1. The monoacylglycerol acyltransferase (MGAT) enzyme family is known to be involved in dietary fat absorption. There was no overlap between the linkage regions and the associated SNPs. Our results show that genetic effects influencing weight and BMI are shared across diverse European populations, even though some of these populations have experienced recent population bottlenecks and/or been affected by genetic drift. The analysis enabled us to identify a new candidate gene, MGAT1, associated with weight in women.
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| 6. |
- Kao, Daniela, et al.
(författare)
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A Monosaccharide Residue Is Sufficient to Maintain Mouse and Human IgG Subclass Activity and Directs IgG Effector Functions to Cellular Fc Receptors.
- 2015
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 13:11, s. 2376-2385
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Tidskriftsartikel (refereegranskat)abstract
- Immunoglobulin G (IgG) glycosylation modulates antibody activity and represents a major source of heterogeneity within antibody preparations. Depending on their glycosylation pattern, individual IgG glycovariants present in recombinant antibody preparations may trigger effects ranging from enhanced pro-inflammatory activity to increased anti-inflammatory activity. In contrast, reduction of IgG glycosylation beyond the central mannose core is generally believed to result in impaired IgG activity. However, this study reveals that a mono- or disaccharide structure consisting of one N-acetylglucosamine with or without a branching fucose residue is sufficient to retain the activity of the most active human and mouse IgG subclasses in vivo and further directs antibody activity to cellular Fcγ receptors. Notably, the activity of minimally glycosylated antibodies is not predicted by in vitro assays based on a monomeric antibody-Fcγ-receptor interaction analysis, whereas in vitro assay systems using immune complexes are more suitable to predict IgG activity in vivo.
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| 7. |
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| 8. |
- Lauc, Gordan, et al.
(författare)
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Genomics Meets Glycomics-The First GWAS Study of Human N-Glycome Identifies HNF1 alpha as a Master Regulator of Plasma Protein Fucosylation
- 2010
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 6:12, s. e1001256-
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Tidskriftsartikel (refereegranskat)abstract
- Over half of all proteins are glycosylated, and alterations in glycosylation have been observed in numerous physiological and pathological processes. Attached glycans significantly affect protein function; but, contrary to polypeptides, they are not directly encoded by genes, and the complex processes that regulate their assembly are poorly understood. A novel approach combining genome-wide association and high-throughput glycomics analysis of 2,705 individuals in three population cohorts showed that common variants in the Hepatocyte Nuclear Factor 1 alpha (HNF1 alpha) and fucosyltransferase genes FUT6 and FUT8 influence N-glycan levels in human plasma. We show that HNF1 alpha and its downstream target HNF4 alpha regulate the expression of key fucosyltransferase and fucose biosynthesis genes. Moreover, we show that HNF1 alpha is both necessary and sufficient to drive the expression of these genes in hepatic cells. These results reveal a new role for HNF1 alpha as a master transcriptional regulator of multiple stages in the fucosylation process. This mechanism has implications for the regulation of immunity, embryonic development, and protein folding, as well as for our understanding of the molecular mechanisms underlying cancer, coronary heart disease, and metabolic and inflammatory disorders.
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| 9. |
- Lauc, Gordan, et al.
(författare)
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Loci Associated with N-Glycosylation of Human Immunoglobulin G Show Pleiotropy with Autoimmune Diseases and Haematological Cancers
- 2013
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 9:1, s. e1003225-
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Tidskriftsartikel (refereegranskat)abstract
- Glycosylation of immunoglobulin G (IgG) influences IgG effector function by modulating binding to Fc receptors. To identify genetic loci associated with IgG glycosylation, we quantitated N-linked IgG glycans using two approaches. After isolating IgG from human plasma, we performed 77 quantitative measurements of N-glycosylation using ultra-performance liquid chromatography (UPLC) in 2,247 individuals from four European discovery populations. In parallel, we measured IgG N-glycans using MALDI-TOF mass spectrometry (MS) in a replication cohort of 1,848 Europeans. Meta-analysis of genome-wide association study (GWAS) results identified 9 genome-wide significant loci (P<2.27x10(-9)) in the discovery analysis and two of the same loci (B4GALT1 and MGAT3) in the replication cohort. Four loci contained genes encoding glycosyltransferases (ST6GAL1, B4GALT1, FUT8, and MGAT3), while the remaining 5 contained genes that have not been previously implicated in protein glycosylation (IKZF1, IL6ST-ANKRD55, ABCF2-SMARCD3, SUV420H1, and SMARCB1-DERL3). However, most of them have been strongly associated with autoimmune and inflammatory conditions (e. g., systemic lupus erythematosus, rheumatoid arthritis, ulcerative colitis, Crohn's disease, diabetes type 1, multiple sclerosis, Graves' disease, celiac disease, nodular sclerosis) and/or haematological cancers (acute lymphoblastic leukaemia, Hodgkin lymphoma, and multiple myeloma). Follow-up functional experiments in haplodeficient Ikzf1 knock-out mice showed the same general pattern of changes in IgG glycosylation as identified in the meta-analysis. As IKZF1 was associated with multiple IgG N-glycan traits, we explored biomarker potential of affected N-glycans in 101 cases with SLE and 183 matched controls and demonstrated substantial discriminative power in a ROC-curve analysis (area under the curve=0.842). Our study shows that it is possible to identify new loci that control glycosylation of a single plasma protein using GWAS. The results may also provide an explanation for the reported pleiotropy and antagonistic effects of loci involved in autoimmune diseases and haematological cancer.
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| 10. |
- Louca, Panayiotis, et al.
(författare)
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Plasma protein N-glycome composition associates with postprandial lipaemic response
- 2023
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Ingår i: BMC Medicine. - 1741-7015. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: A dysregulated postprandial metabolic response is a risk factor for chronic diseases, including type 2 diabetes mellitus (T2DM). The plasma protein N-glycome is implicated in both lipid metabolism and T2DM risk. Hence, we first investigate the relationship between the N-glycome and postprandial metabolism and then explore the mediatory role of the plasma N-glycome in the relationship between postprandial lipaemia and T2DM. Methods: We included 995 individuals from the ZOE-PREDICT 1 study with plasma N-glycans measured by ultra-performance liquid chromatography at fasting and triglyceride, insulin, and glucose levels measured at fasting and following a mixed-meal challenge. Linear mixed models were used to investigate the associations between plasma protein N-glycosylation and metabolic response (fasting, postprandial (C max), or change from fasting). A mediation analysis was used to further explore the relationship of the N-glycome in the prediabetes (HbA1c = 39–47 mmol/mol (5.7–6.5%))–postprandial lipaemia association. Results: We identified 36 out of 55 glycans significantly associated with postprandial triglycerides (C max β ranging from -0.28 for low-branched glycans to 0.30 for GP26) after adjusting for covariates and multiple testing (p adjusted < 0.05). N-glycome composition explained 12.6% of the variance in postprandial triglycerides not already explained by traditional risk factors. Twenty-seven glycans were also associated with postprandial glucose and 12 with postprandial insulin. Additionally, 3 of the postprandial triglyceride–associated glycans (GP9, GP11, and GP32) also correlate with prediabetes and partially mediate the relationship between prediabetes and postprandial triglycerides. Conclusions: This study provides a comprehensive overview of the interconnections between plasma protein N-glycosylation and postprandial responses, demonstrating the incremental predictive benefit of N-glycans. We also suggest a considerable proportion of the effect of prediabetes on postprandial triglycerides is mediated by some plasma N-glycans.
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