N-Glycosylation Profiles of Immunoglobulin G and Future Cardiovascular Events.

BACKGROUND: Posttranslational glycosylation of IgG can modulate its inflammatory capacity through structural variations. We examined the association of baseline IgG N-glycans and an IgG glycan score with incident cardiovascular disease (CVD). METHODS: IgG N-glycans were measured in 2 nested CVD case-control studies: JUPITER (Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin; NCT00239681; primary prevention; discovery; Npairs=162); and TNT trial (Treating to New Targets; NCT00327691; secondary prevention; validation; Npairs=397). Using conditional logistic regression, we investigated the association of future CVD with baseline IgG N-glycans and a glycan score adjusting for clinical risk factors (statin treatment, age, sex, race, lipids, hypertension, and smoking) in JUPITER. Significant associations were validated in TNT, using a similar model further adjusted for diabetes. Using least absolute shrinkage and selection operator regression, an IgG glycan score was derived in JUPITER as a linear combination of selected IgG N-glycans. RESULTS: Six IgG N-glycans were associated with CVD in both studies: an agalactosylated glycan (IgG-GP4) was positively associated, while 3 digalactosylated glycans (IgG glycan peaks 12, 13, 14) and 2 monosialylated glycans (IgG glycan peaks 18, 20) were negatively associated with CVD after multiple testing correction (overall false discovery rate <0.05). Four selected IgG N-glycans comprised the IgG glycan score, which was associated with CVD in JUPITER (adjusted hazard ratio per glycan score SD, 2.08 [95% CI, 1.52-2.84]) and validated in TNT (adjusted hazard ratio per SD, 1.20 [95% CI, 1.03-1.39]). The area under the curve changed from 0.693 for the model without the score to 0.728 with the score in JUPITER (PLRT=1.1×10-6) and from 0.635 to 0.637 in TNT (PLRT=0.017). CONCLUSIONS: An IgG N-glycan profile was associated with incident CVD in 2 populations (primary and secondary prevention), involving an agalactosylated glycan associated with increased risk of CVD, while several digalactosylated and sialylated IgG glycans associated with decreased risk. An IgG glycan score was positively associated with future CVD.

Human-specific features and developmental dynamics of the brain N-glycome.

Comparative "omics" studies have revealed unique aspects of human neurobiology, yet an evolutionary perspective of the brain N-glycome is lacking. We performed multiregional characterization of rat, macaque, chimpanzee, and human brain N-glycomes using chromatography and mass spectrometry and then integrated these data with complementary glycotranscriptomic data. We found that, in primates, the brain N-glycome has diverged more rapidly than the underlying transcriptomic framework, providing a means for rapidly generating additional interspecies diversity. Our data suggest that brain N-glycome evolution in hominids has been characterized by an overall increase in complexity coupled with a shift toward increased usage of α(2-6)-linked N-acetylneuraminic acid. Moreover, interspecies differences in the cell type expression pattern of key glycogenes were identified, including some human-specific differences, which may underpin this evolutionary divergence. Last, by comparing the prenatal and adult human brain N-glycomes, we uncovered region-specific neurodevelopmental pathways that lead to distinct spatial N-glycosylation profiles in the mature brain.

Breathlessness and "exacerbation" questions predictive for incident COPD (MARKO study): data after two years of follow-up.

Aims: To determine the predictability of the MARKO questionnaire and/or its domains, individually or in combination with other markers and characteristics (age, gender, smoking history, lung function, 6-min walk test (6 MWT), exhaled breath temperature (EBT), and hsCRP for the incident chronic obstructive pulmonary disease (COPD) in subjects at risk over 2 years follow-up period). Participants and Methods: Patients, smokers/ex-smokers with >20 pack-years, aged 40-65 years of both sexes were recruited and followed for 2 years. After recruitment and signing the informed consent at the GP, a detailed diagnostic workout was done by the pulmonologist; they completed three self-assessment questionnaires-MARKO, SGRQ and CAT, detailed history and physical, laboratory (CBC, hsCRP), lung function tests with bronchodilator and EBT. At the 2 year follow-up visit they performed: the same three self-assessment questionnaires, history and physical, lung function tests and EBT. Results: A sample of 320 subjects (41.9% male), mean (SD) age 51.9 (7.4) years with 36.4 (17.4) pack-years of smoking was reassessed after 2.1 years. Exploratory factor analysis of MARKO questionnaire isolated three distinct domains (breathlessness and fatigue, "exacerbations", cough and expectorations). We have determined a rate for incident COPD that was 4.911/100 person-years (95% CI [3.436-6.816]). We found out that questions about breathlessness and "exacerbations", and male sex were predictive of incident COPD after two years follow-up (AUC 0.79, 95% CI [0.74-0.84], p < 0.001). When only active smokers were analyzed a change in EBT after a cigarette (ΔEBT) was added to a previous model (AUC 0.83, 95% CI [0.78-0.88], p < 0.001). Conclusion: Our preliminary data shows that the MARKO questionnaire combined with EBT (change after a cigarette smoke) could potentially serve as early markers of future COPD in smokers.

Mapping of the gene network that regulates glycan clock of ageing.

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.

Higher MRI lesion load in multiple sclerosis is related to the N-glycosylation changes of cerebrospinal fluid immunoglobulin G.

BACKGROUND: Intrathecal clonal expansion of antibody-producing plasma cells in multiple sclerosis (MS) perpetuates central nervous system injury and is associated with active demyelination. Immunoglobulin G (IgG) effector functions are modulated by linked N-glycan structures. The aim of the study was to detect potential differences in N-glycosylation of IgG in serum and cerebrospinal fluid (CSF) and total sera proteins between people with MS and those in whom the diagnosis of MS was excluded. Furthermore, we investigated the association with standard laboratory biomarkers of intrathecal inflammation as well as clinical and neuroradiological disease activity. METHODS: This cross-sectional study included patients with suspected demyelinating disease. MS diagnosis was based on the 2017 McDonald criteria and controls were patients with excluded MS diagnosis. N-glycans were compared with Expanded Disability Status Scale (EDSS), magnetic resonance imaging (MRI) markers of disease activity and biomarkers of intrathecal inflammation (cell count, CSF-IgG concentration, percentage of intrathecal IgG, oligoclonal bands (OCB), virus-specific antibody index (MRZH reaction)). RESULTS: Differences between groups were observed only in the CSF-IgG N-glycome. In MS, the presence of bisecting N-acetylglucosamine (Padj=2.63E-05) and monogalactosylation (Padj=1.49E-06) were more abundant and associated with positive OCBs. N-glycans monogalactosylated at the α6 arm FA2[6]G1 (r = 0.56) and FA2[6]BG1 (r = 0.45) correlated with percentage of intrathecal IgG, but not total CSF-IgG. This trait was also more abundant in MRZH positive people with MS who had higher MRI lesion load (P = 0.018) but unrelated to active lesions or EDSS. CONCLUSIONS: More abundant monogalactosylation of intrathecally synthesized IgG is the most prominent trait in MS and is associated with higher MRI lesion load.

The N-Glycosylation of Total Plasma Proteins and IgG in Atrial Fibrillation.

Atrial fibrillation is a disease with a complex pathophysiology, whose occurrence and persistence are caused not only by aberrant electrical signaling in the heart, but by the development of a susceptible heart substrate. These changes, such as the accumulation of adipose tissue and interstitial fibrosis, are characterized by the presence of inflammation. N-glycans have shown great promise as biomarkers in different diseases, specifically those involving inflammatory changes. To assess the changes in the N-glycosylation of the plasma proteins and IgG in atrial fibrillation, we analyzed the N-glycosylation of 172 patients with atrial fibrillation, before and six months after a pulmonary vein isolation procedure, with 54 cardiovascularly healthy controls. An analysis was performed using ultra-high-performance liquid chromatography. We found one oligomannose N-glycan structure from the plasma N-glycome and six IgG N-glycans, mainly revolving around the presence of bisecting N-acetylglucosamine, that were significantly different between the case and control groups. In addition, four plasma N-glycans, mostly oligomannose structures and a derived trait that was related to them, were found to be different in the patients who experienced an atrial fibrillation recurrence during the six-month follow-up. IgG N-glycosylation was extensively associated with the CHA2DS2-VASc score, confirming its previously reported associations with the conditions that make up the score. This is the first study looking at the N-glycosylation patterns in atrial fibrillation and warrants further investigation into the prospect of glycans as biomarkers for atrial fibrillation.

Storage stability and HILIC-UHPLC-FLR analysis of immunoglobulin G N-glycome from saliva.

Immunoglobulin G (IgG) is the most abundant antibody in the blood and plays a critical role in host immune defense against infectious agents. Glycosylation is known to modulate the effector functions of IgG and is involved in disease development and progression. It is no surprise that the N-glycome of IgG from plasma has already been proposed as a biomarker for various physiological and pathological conditions. However, because saliva is easy to collect, it could be useful for exploring the functional role of salivary IgG N-glycosylation and its potential as a diagnostic biomarker. Therefore, in this study, we described a method for N-glycome analysis of IgG from saliva samples. Salivary IgG N-glycans were analyzed by ultra-high-performance liquid chromatography based on hydrophilic interactions with fluorescence detection (HILIC-UHPLC-FLR). In addition, we compared IgG N-glycan profiles from saliva with those from plasma, assessed the stability of salivary IgG N-glycan profiles under different storage conditions, and evaluated the effects of using a saliva preservation medium. This study provides an ultrasensitive UHPLC method for the analysis of total IgG N-glycosylation from saliva, gives insight into storage stability of salivary IgG, and highlights its (dis)advantages for further biomarker-related research.

IgG N-Glycosylation Is Altered in Coronary Artery Disease.

Coronary artery disease (CAD) is the most common cardiovascular disease (CVD), and previous studies have shown a significant association between N-glycosylation, a highly regulated posttranslational modification, and the development of atherosclerotic plaques. Our aim was to determine whether the N-glycome of immunoglobulin G (IgG) is associated with CAD, as N-glycans are known to alter the effector functions of IgG, which may enhance the inflammatory response in CAD. Therefore, in this study, we isolated IgG from subjects with coronary atherosclerosis (CAD+) and from subjects with clean coronaries (CAD-). The purified IgGs were denatured and enzymatically deglycosylated, and the released and fluorescently labelled N-glycans were analysed by ultra-high performance liquid chromatography based on hydrophilic interactions with fluorescence detection (HILIC-UHPLC-FLR). Sex-stratified analysis of 316 CAD- and 156 CAD+ cases revealed differences in IgG N-glycome composition. The most notable differences were observed in women, where the presence of sialylated N-glycan structures was negatively associated with CAD. The obtained chromatograms provide insight into the IgG N-glycome composition in CAD as well as the biomarker potential of IgG N-glycans in CAD.

Human-specific features and developmental dynamics of the brain N-glycome.

Comparative "omics" studies have revealed unique aspects of human neurobiology, yet an evolutionary perspective of the brain N-glycome is lacking. Here, we performed multi-regional characterization of rat, macaque, chimpanzee, and human brain N-glycomes using chromatography and mass spectrometry, then integrated these data with complementary glycotranscriptomic data. We found that in primates the brain N-glycome has evolved more rapidly than the underlying transcriptomic framework, providing a mechanism for generating additional diversity. We show that brain N-glycome evolution in hominids has been characterized by an increase in complexity and α(2-6)-linked N-acetylneuraminic acid along with human-specific cell-type expression of key glycogenes. Finally, by comparing the prenatal and adult human brain N-glycome, we identify region-specific neurodevelopmental pathways that lead to distinct spatial N-glycosylation profiles in the mature brain. One-Sentence Summary: Evolution of the human brain N-glycome has been marked by an increase in complexity and a shift in sialic acid linkage.

Susceptibility of Human Plasma N-glycome to Low-Calorie and Different Weight-Maintenance Diets.

Aberrant plasma protein glycosylation is associated with a wide range of diseases, including diabetes, cardiovascular, and immunological disorders. To investigate plasma protein glycosylation alterations due to weight loss and successive weight-maintenance diets, 1850 glycomes from participants of the Diogenes study were analyzed using Ultra-High-Performance Liquid Chromatography (UHPLC). The Diogenes study is a large dietary intervention study in which participants were subjected to a low-calorie diet (LCD) followed by one of five different weight-maintenance diets in a period of 6 months. The most notable alterations of the plasma glycome were 8 weeks after the subjects engaged in the LCD; a significant increase in low-branched glycan structures, accompanied by a decrease in high-branched glycan structures. After the LCD period, there was also a significant rise in N-glycan structures with antennary fucose. Interestingly, we did not observe significant changes between different diets, and almost all effects we observed immediately after the LCD period were annulled during the weight-maintenance diets period.

Effects of low-calorie and different weight-maintenance diets on IgG glycome composition.

Obesity-induced inflammation activates the adaptive immune system by altering immunoglobulin G (IgG) glycosylation in a way to produce more proinflammatory antibodies. The IgG glycome has already been well studied, and its alterations are correlated with a high body mass index (BMI) and central adiposity. Still, the IgG N-glycome susceptibility to different dietary regimes for weight control after the initial weight loss has not been studied. To explore changes in IgG glycosylation induced by weight loss and subsequent weight-maintenance diets, we analyzed 1,850 IgG glycomes from subjects in a dietary intervention Diogenes study. In this study, participants followed a low-calorie diet (LCD) providing 800 kcal/d for 8 weeks, followed by one of five weight-maintenance diets over a 6-month period. The most significant alteration of the IgG N-glycome was present 8 weeks after the subjects underwent an LCD, a statistically significant decrease of agalactosylated and the increase of sialylated N glycans. In the follow-up period, the increase in glycans with bisecting GlcNAc and the decrease in sialylated glycans were observed. Those changes were present regardless of the diet type, and we did not observe significant changes between different diets. However, it should be noted that in all five diet groups, there were individuals who prominently altered their IgG glycome composition in either proinflammatory or anti-inflammatory directions.

Differences in Immunoglobulin G Glycosylation Between Influenza and COVID-19 Patients.

The essential role of immunoglobulin G (IgG) in immune system regulation and combatting infectious diseases cannot be fully recognized without an understanding of the changes in its N-glycans attached to the asparagine 297 of the Fc domain that occur under such circumstances. These glycans impact the antibody stability, half-life, secretion, immunogenicity, and effector functions. Therefore, in this study, we analyzed and compared the total IgG glycome-at the level of individual glycan structures and derived glycosylation traits (sialylation, galactosylation, fucosylation, and bisecting N-acetylglucosamine (GlcNAc))-of 64 patients with influenza, 77 patients with coronavirus disease 2019 (COVID-19), and 56 healthy controls. Our study revealed a significant decrease in IgG galactosylation, sialylation, and bisecting GlcNAc (where the latter shows the most significant decrease) in deceased COVID-19 patients, whereas IgG fucosylation was increased. On the other hand, IgG galactosylation remained stable in influenza patients and COVID-19 survivors. IgG glycosylation in influenza patients was more time-dependent: In the first seven days of the disease, sialylation increased and fucosylation and bisecting GlcNAc decreased; in the next 21 days, sialylation decreased and fucosylation increased (while bisecting GlcNAc remained stable). The similarity of IgG glycosylation changes in COVID-19 survivors and influenza patients may be the consequence of an adequate immune response to enveloped viruses, while the observed changes in deceased COVID-19 patients may indicate its deviation.

N-Glycosylation and Inflammation; the Not-So-Sweet Relation.

Chronic inflammation is the main feature of many long-term inflammatory diseases such as autoimmune diseases, metabolic disorders, and cancer. There is a growing number of studies in which alterations of N-glycosylation have been observed in many pathophysiological conditions, yet studies of the underlying mechanisms that precede N-glycome changes are still sparse. Proinflammatory cytokines have been shown to alter the substrate synthesis pathways as well as the expression of glycosyltransferases required for the biosynthesis of N-glycans. The resulting N-glycosylation changes can further contribute to disease pathogenesis through modulation of various aspects of immune cell processes, including those relevant to pathogen recognition and fine-tuning the inflammatory response. This review summarizes our current knowledge of inflammation-induced N-glycosylation changes, with a particular focus on specific subsets of immune cells of innate and adaptive immunity and how these changes affect their effector functions, cell interactions, and signal transduction.

Transcriptomic taxonomy and neurogenic trajectories of adult human, macaque, and pig hippocampal and entorhinal cells.

The hippocampal-entorhinal system supports cognitive functions, has lifelong neurogenic capabilities in many species, and is selectively vulnerable to Alzheimer's disease. To investigate neurogenic potential and cellular diversity, we profiled single-nucleus transcriptomes in five hippocampal-entorhinal subregions in humans, macaques, and pigs. Integrated cross-species analysis revealed robust transcriptomic and histologic signatures of neurogenesis in the adult mouse, pig, and macaque but not humans. Doublecortin (DCX), a widely accepted marker of newly generated granule cells, was detected in diverse human neurons, but it did not define immature neuron populations. To explore species differences in cellular diversity and implications for disease, we characterized subregion-specific, transcriptomically defined cell types and transitional changes from the three-layered archicortex to the six-layered neocortex. Notably, METTL7B defined subregion-specific excitatory neurons and astrocytes in primates, associated with endoplasmic reticulum and lipid droplet proteins, including Alzheimer's disease-related proteins. This resource reveals cell-type- and species-specific properties shaping hippocampal-entorhinal neurogenesis and function.

Attitudes of Croatian pulmonologists concerning obstacles to earlier, more appropriate use of biologics in severe asthma: Survey results.

AIMS: Biologics have been proven efficacious for patients with severe asthma (SA). It is essential to diagnose such individuals correctly. This study was designed to survey pulmonologists to identify barriers to early diagnosis and subsequent appropriate use of biologics for SA in Croatia. METHODS: A pulmonologist group with expertise in SA developed the initial list of questions, with the final questionnaire created according to a 2-round Delphi method. The resulting survey consisted of 23 items consequently divided into 4 domains: 1) Pulmonologists' demographics and professional experiences; 2) Concerns about asthma management; 3) Attitudes toward SA diagnosis; and 4) Beliefs and attitudes regarding the use of biologics in managing SA. The given answers represented the respondents' estimates. RESULTS: Eighty-four surveys were analyzed, with pulmonologists observing that general practitioners often inaccurately diagnose asthma and treat acute exacerbations. Although specialist centers are capably and correctly equipped, the time to diagnose patients with SA is approximately 3.5 months, with initial use of biologics delayed an additional 2 months. The primary indications for prescribing biologics are conventional therapy with oral glucocorticoids (91.7%) and frequent acute exacerbations (82.1%). In addition to improper diagnosis (64.3%), many patients with SA do not receive the indicated biologics owing to strict administrative directives for reimbursement (70.2%) or limited hospital resources (57.1%). LIMITATIONS: The limitations of this survey include the subjective nature of the collected data, the relatively small sample size, and the lack of the biologic efficacy evaluation. CONCLUSIONS: Croatian pulmonologists observed that a significant number of patients with SA who are eligible for biologics are not prescribed them, largely because of an inaccurate and/or delayed diagnosis, a delayed referral to a specialist center, highly restrictive criteria for reimbursement, and/or institutional budgetary limitations.

Is the extent of left atrial fibrosis associated with body mass index in patients undergoing pulmonary vein isolation for atrial fibrillation?

BACKGROUND: Left atrial (LA) fibrosis is associated with a higher rate of recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI). Body mass index (BMI) is strongly associated with the prevalence of AF, but there is insufficient data about the association between BMI and LA fibrosis. AIMS: The aim of the study was to examine the association between LA fibrosis and BMI in patients with AF undergoing PVI. METHODS: In 114 patients an electro-anatomical voltage map was created using the CARTO 3 three-dimensional system before PVI. The total fibrosis area (voltage criteria ≤0.5 mV), percentage, and the number of fibrotic areas were calculated. A general linear model was used to determine the differences in BMI with confounders between groups of patients with differing extents of fibrosis and numbers of focuses. RESULTS: Advanced fibrosis was found in 53 (47%) patients, in up to 9 areas with a median of 2 and an interquartile range (IQR) of 0-3. The median total fibrotic area was 27.3 cm2 with an IQR of 0.1-30.3 cm2. Patients were stratified by percentage of fibrotic area: <5%, 5%-20%, 20%-35%, and above 35%; no significant difference in mean BMI was found between the groups (P = 0.57). When stratified by the number of fibrotic areas (0, 1, 2, and ≥3 fibrotic areas), no difference in BMI was noted between the groups (P = 0.67). CONCLUSIONS: Fibrosis of the LA, as the strongest predictor of AF recurrence after PVI, does not correlate with BMI in patients with AF where PVI is indicated.

N-glycosylation profiling of Type 2 diabetes mellitus from baseline to follow-up: an observational study in a Ghanaian population.

Aim: The study sought to determine the patterns of N-glycan profiles among Type 2 diabetes mellitus (T2DM) patients over a 6-month period. Materials & methods: Biochemical and clinical data were obtained from 253 T2DM patients at baseline and follow-up. Ultra-performance liquid chromatography and statistical methods were applied for N-glycan profiling. Results: The coefficients of variation were 28% and 29% at baseline and follow-up, respectively, whereas the range of N-glycan variability was from 11% to 56%. Apart from GP1 (FA2) and GP29 (FA3G3S [3,3,3]3), the intra-individual variations of N-glycan peaks were not statistically significant. Conclusion: N-glycan profiles were stable over 6-month period in T2DM patients and could be used to monitor biochemical changes in relation with T2DM comorbidities.

Replication of 15 loci involved in human plasma protein N-glycosylation in 4802 samples from four cohorts.

Human protein glycosylation is a complex process, and its in vivo regulation is poorly understood. Changes in glycosylation patterns are associated with many human diseases and conditions. Understanding the biological determinants of protein glycome provides a basis for future diagnostic and therapeutic applications. Genome-wide association studies (GWAS) allow to study biology via a hypothesis-free search of loci and genetic variants associated with a trait of interest. Sixteen loci were identified by three previous GWAS of human plasma proteome N-glycosylation. However, the possibility that some of these loci are false positives needs to be eliminated by replication studies, which have been limited so far. Here, we use the largest set of samples so far (4802 individuals) to replicate the previously identified loci. For all but one locus, the expected replication power exceeded 95%. Of the 16 loci reported previously, 15 were replicated in our study. For the remaining locus (near the KREMEN1 gene), the replication power was low, and hence, replication results were inconclusive. The very high replication rate highlights the general robustness of the GWAS findings as well as the high standards adopted by the community that studies genetic regulation of protein glycosylation. The 15 replicated loci present a good target for further functional studies. Among these, eight loci contain genes encoding glycosyltransferases: MGAT5, B3GAT1, FUT8, FUT6, ST6GAL1, B4GALT1, ST3GAL4 and MGAT3. The remaining seven loci offer starting points for further functional follow-up investigation into molecules and mechanisms that regulate human protein N-glycosylation in vivo.

Increased yield of enzymatic synthesis by chromatographic selection of different N-glycoforms of yeast invertase.

Invertases are glycosidases applied for synthesis of alkyl glycosides that are important and effective surfactants. Stability of invertases in the environment with increased content of organic solvent is crucial for increase of productivity of glycosidases. Their stability is significantly influenced by N-glycosylation. However, yeast N-glycosylation pathways may synthesize plethora of N-glycan structures. A total natural crude mixture of invertase glycoforms (EINV) extracted from Saccharomyces cerevisiae was subfractionated by anion-exchange chromatography on industrial monolithic supports to obtain different glycoforms (EINV1-EINV3). Separated glycoforms exhibited different stabilities in water-alcohol solutions that are in direct correlation with the amount of phosphate bound to N-glycans. Observed differences in stability of different invertase glycoforms were used to improve productivity of methyl ß-d-fructofuranoside (MF) synthesis. The efficiency and yield of MF synthesis were improved more than 50% when the most stabile glycoform bearing the lowest amount of phosphorylated N-glycans is selected and utilized. These data underline the importance of analysis of glycan structures attached to glycoproteins, demonstrate different impact of N-glycans on the surface charge and enzyme stability in regard to particular reaction environment, and provide a platform for improvement of yield of industrial enzymatic synthesis by chromatographic selection of glycoforms on monolithic supports.

Global variability of the human IgG glycome.

Immunoglobulin G (IgG) is the most abundant serum antibody which structural characteristics and effector functions are modulated through the attachment of various sugar moieties called glycans. Composition of the IgG N-glycome changes with age of an individual and in different diseases. Variability of IgG glycosylation within a population is well studied and is known to be affected by both genetic and environmental factors. However, global inter-population differences in IgG glycosylation have never been properly addressed. Here we present population-specific N-glycosylation patterns of IgG, analyzed in 5 different populations totaling 10,482 IgG glycomes, and of IgG's fragment crystallizable region (Fc), analyzed in 2,579 samples from 27 populations sampled across the world. Country of residence associated with many N-glycan features and the strongest association was with monogalactosylation where it explained 38% of variability. IgG monogalactosylation strongly correlated with the development level of a country, defined by United Nations health and socioeconomic development indicators, and with the expected lifespan. Subjects from developing countries had low levels of IgG galactosylation, characteristic for inflammation and ageing. Our results suggest that citizens of developing countries may be exposed to environmental factors that can cause low-grade chronic inflammation and the apparent increase in biological age.