Ischemic stroke is associated with the pro-inflammatory potential of N-glycosylated immunoglobulin G

Immunoglobulin G N-Glycosylation and Inflammatory Factors: Analysis of Biomarkers for the Diagnosis of Moyamoya Disease

Purpose

N-glycosylation-modified immunoglobulin G (IgG) is crucial for managing the inflammatory response balance and significantly influences the progression of many inflammatory disorders. IgG N-glycosylation has been demonstrated to correlate with many risk factors for moyamoya disease (MMD), such as hypertension, diabetes, and dyslipidemia. This research aimed to evaluate the diagnostic efficacy of IgG N-glycosylation for MMD.

Methods

Ultra-high-performance liquid chromatography (UPLC) was employed to examine the properties of IgG N-glycans in blood samples from 116 patients with MMD and 126 controls, resulting in the quantitative determination of 24 initial glycan peaks (GP). Through the Lasso algorithm and multivariate logistic regression analysis, we constructed a diagnostic model based on initial glycans and related inflammatory factors to distinguish MMD patients from healthy individuals.

Results

After adjusting for potential confounding variables, including age, fasting blood glucose (FBG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), neutrophil count (NEUT), and lymphocyte count (LYM), our study demonstrated significant differences in the characteristics of 6 initial glycans and 16 derived glycans between the MMD cohort and the healthy control group. Based on the above findings, we developed an MMD diagnostic model that combines initial glycans with related inflammatory factors. The curve of receiver operating characteristic (ROC) was utilized to evaluate the model's ability to distinguish MMD patients from healthy subjects. The findings indicated a robust area under the curve (AUC) of 0.963 (95% CI: 0.940, 0.987).

Conclusion

This study found that the occurrence and progression of MMD may be associated with decreased levels of sialylation, galactosylation, and fucosylation and increased bisecting GlcNAc. This may be involved in the occurrence of MMD by regulating the balance of inflammation. Therefore, the IgG N-glycosylation is expected to become a potential biomarker for the screening of MMD.

Profiling of IgG N-glycosylation for axial spondyloarthritis and other rheumatic diseases

BACKGROUND

Axial spondyloarthritis (axSpA) is an inflammatory rheumatic disease with challenges in diagnosis and disease activity assessment. While alterations in immunoglobulin G (IgG) N-glycosylation have been observed in varied rheumatic diseases, those in axSpA remains unclear. This study aims to explore the role of IgG N-glycan profiles in diagnosis and disease activity of axSpA.

METHODS

A clinical case-control study was conducted involving patients with axSpA (n = 138), systemic lupus erythematosus (n = 102), rheumatoid arthritis (n = 106), osteoarthritis (n = 33), gout (n = 41) and healthy controls (n = 117). Ultra-performance liquid chromatography was employed to analyze the composition of the serum IgG N-glycome. Associations between IgG N-glycans and axSpA were investigated and compared to healthy controls and other four rheumatic diseases. The relationship among IgG N-glycosylation, disease activity, and inflammatory cytokines of axSpA patients were analyzed. The receiver operating characteristic (ROC) curve analysis was applied to evaluate the diagnostic/classification performance of IgG N-glycans to distinguish axSpA and its disease activity.

RESULTS

In patients with axSpA, the abundances of IgG galactosylation and sialylation were significantly lower than healthy controls, while the abundance of fucosylation was higher than the other four studied rheumatic diseases. Additionally, two asialylated IgG N-glycans (FA2 and FA2 [3]G1) were associated with axSpA, with adjusted odds ratios (AORs) of 5.62 (95% CI: 3.41-9.24) and 0.33 (95% CI: 0.22-0.50), respectively. Notably, decreased FA2 [3]G1 emerged as a characteristic IgG N-glycan associated with all five studied rheumatic diseases, while decreased FA2BG2S2 was a unique IgG N-glycan differentiating axSpA from the other four rheumatic diseases. Furthermore, FA2 displayed positive association with disease activity indicators (ASDAS-CRP, SPARCC-SIJ and SPARCC-spine) in axSpA. IgG N-glycans, particularly FA2 [3]G1, FA2BG2S2 and FA2, demonstrated canonical correlation with inflammatory cytokines, including interleukin-23 and tumor necrosis factor α, in axSpA (r = 0.519, P = 0.017).

CONCLUSIONS

Specific IgG N-glycans hold potential as novel biomarkers to enhance diagnosis and disease activity assessment in axSpA management.

Altered Pattern of Serum N-Glycome in Subarachnoid Hemorrhage and Cerebral Vasospasm

Background: Subarachnoid hemorrhage is a serious condition caused by ruptured intracranial aneurysms, resulting in severe disability mainly in young adults. Cerebral vasospasm is one of the most common complication of subarachnoid hemorrhage; thus, active prevention is key to improve the prognosis. The glycosylation of proteins is a critical quality attribute which is reportedly altered in patients diagnosed with acute ischemic stroke. In this study, we examined the N-glycosylation profile of serum glycoproteins in patients with subarachnoid hemorrhage without vasospasm compared to patients with vasospasm. Methods: The serum N-glycans were released by PNGase F (Peptide: N-glycosidase F) digestion and subsequently labeled by procainamide via reductive amination. The samples were analyzed by hydrophilic-interaction liquid chromatography after solid-phase extraction-based sample purification. Results: Besides the glycosylation pattern, we also investigated the biomarkers following subarachnoid hemorrhage. Multiple statistical analyses were performed in order to find significant differences and identify potential prediction factors of cerebral vasospasm. Significant differences were identified such as higher sialylation on bi-, tri-, and tetra-antennary structures in patients with subarachnoid hemorrhage and cerebral vasospasm. Conclusions: Our results suggest that glycosylation analysis can improve the identification of patients with cerebral vasospasm in combination with laboratory parameters.

Predicting psychiatric risk: IgG N-glycosylation traits as biomarkers for mental health

Background

Growing evidence suggests that chronic inflammation, resulting from intricate immune system interactions, significantly contributes to the onset of psychiatric disorders. Observational studies have identified a link between immunoglobulin G (IgG) N-glycosylation and various psychiatric conditions, but the causality of these associations remains unclear.

Methods

Genetic variants for IgG N-glycosylation traits and psychiatric disorders were obtained from published genome-wide association studies. The inverse-variance-weighted (IVW) method, MR-Egger, and weighted median were used to estimate causal effects. The Cochran's Q test, MR-Egger intercept test, leave-one-out analyses, and MR-PRESSO global test were used for sensitivity analyses.

Results

In the Psychiatric Genomics Consortium (PGC) database, genetically predicted IGP7 showed a protective role in schizophrenia (SCZ), major depressive disorder (MDD), and bipolar disorder (BIP), while elevated IGP34, and IGP57 increased SCZ risk. High levels of IGP21 were associated with an increased risk of post-traumatic stress disorder (PTSD), while elevated levels of IGP22 exhibited a causal association with a decreased risk of attention-deficit/hyperactivity disorder (ADHD). No causal relationship between IgG N-glycan traits and autism spectrum disorder (ASD) and no evidence of reverse causal associations was found.

Conclusion

Here, we demonstrate that IgG N-glycan traits have a causal relationship with psychiatric disorders, especially IGP7's protective role, offering new insights into their pathogenesis. Our findings suggest potential strategies for predicting and intervening in psychiatric disorder risk through IgG N-glycan traits.

Potentially causal association between immunoglobulin G N-glycans and cardiometabolic diseases: Bidirectional two-sample Mendelian randomization study

BACKGROUND

Observational studies support that altered immunoglobulin G (IgG) N-glycosylation and inflammatory factors are associated with cardiometabolic diseases (CMDs); nevertheless, the causality between them remains unclear.

METHODS

Two-sample Mendelian randomization (MR) analyses were conducted to systematically investigate the bidirectional causality between IgG N-glycans and nine CMDs in both East Asians and Europeans.

RESULTS

In the forward MR analysis, the univariable MR analysis presented suggestive causality of 14 and eight genetically instrumented IgG N-glycans with CMDs in East Asians and Europeans, respectively; the multivariable MR analysis showed that ten and 11 pairs of glycan-CMD associations were identified in East Asian and European populations, respectively. In the reverse MR analysis, based on East Asians and Europeans, the univariable MR analysis presented suggestive causality of seven and 12 genetically instrumented CMDs with IgG N-glycans, respectively; the multivariable MR analysis presented that six and five CMD-glycan causality were found in East Asian and Europeans, respectively.

CONCLUSIONS

The comprehensive MR analyses provide suggestive evidence of bidirectional causality between IgG N-glycans and CMDs. This work helps to understand the molecular mechanism of the occurrence/progression of CMDs, optimize existing and develop new strategies to prevent CMDs, and contribute to the early identification of high-risk groups of CMDs.

Differences in IgG afucosylation between groups with and without carotid atherosclerosis

BACKGROUND

A previous study demonstrated that N-glycosylation profiles of IgG are associated with subclinical atherosclerosis in a British population. However, the generalisability of this finding to other ethnic groups remains to be investigated, and it has yet to account for additional traditional atherosclerotic risk factors. The present study, thus, aims to explore IgG N-glycosylation profiles in Han Chinese with atherosclerosis, and their potential role in atherosclerosis, while controlling for traditional atherosclerotic risk factors.

METHODS

Data of this case-control study were obtained from an established umbrella Health Examination Cohort Study (registration number: ChiCTR2100048740). The investigation was conducted at the Health Care Centre of the First Affiliated Hospital of Shantou University Medical College in China, from August 1, 2021, to July 31, 2022. A sample of 69 carotid atherosclerosis (CAS) cases was recruited from the umbrella cohort, along with 69 controls without carotid atherosclerosis, matched by traditional atherosclerosis-related risk factors, including gender, age, smoking, alcohol consumption, hypertension, diabetes, dyslipidemia and obesity. Subsequently, serum IgG N-glycosylation was profiled using Ultra-Performance Liquid Chromatography.

RESULTS

After propensity score matching, the relative abundance of IgG fucosylation in CAS cases was significantly lower than that in controls [95.32 (92.96, 95.99) vs. 95.96 (94.70, 96.58), P = 0.022]. The traditional atherosclerosis-related risk factors showed no statistically significant difference between CAS cases and controls (P > 0.05).

CONCLUSIONS

The reduced fucosylation of IgG in CAS cases underscores the pivotal role of afucosylation in CAS. Enhancing the inflammatory capability of IgG via initiating antibody-dependent cell-mediated cytotoxicity could be the potential mechanism behind this, which should be further verified by functional studies.

Bidirectional Two-Sample Mendelian Randomization Study of Immunoglobulin G N-Glycosylation and Senescence-Associated Secretory Phenotype

Observational studies revealed changes in Immunoglobulin G (IgG) N-glycosylation during the aging process. However, it lacks causal insights and remains unclear in which direction causal relationships exist. The two-sample bidirectional Mendelian randomization (MR) design was adopted to explore causal associations between IgG N-glycans and the senescence-associated secretory phenotype (SASP). Inverse variance weighted (IVW) and Wald ratio methods were used as the main analyses, supplemented by sensitivity analyses. Forward MR analyses revealed causal associations between the glycan peak (GP) and SASP, including GP6 (odds ratio [OR] = 0.428, 95% confidence interval [CI] = 0.189-0.969) and GP17 (OR = 0.709, 95%CI = 0.504-0.995) with growth/differentiation factor 15 (GDF15), GP19 with an advanced glycosylation end-product-specific receptor (RAGE) (OR = 2.142, 95%  CI  = 1.384-3.316), and GP15 with matrix metalloproteinase 2 (MMP2) (OR = 1.136, 95%  CI =1.008-1.282). The reverse MR indicated that genetic liability to RAGE was associated with increased levels of GP17 (OR = 1.125, 95%  CI  = 1.003-1.261) and GP24 (OR = 1.222, 95%  CI  = 1.046-1.428), while pulmonary and activation-regulated chemokines (PARC) exhibited causal associations with GP10 (OR = 1.269, 95%  CI  = 1.048-1.537) and GP15 (OR = 1.297, 95%  CI = 1.072-1.570). The findings provided suggested evidence on the bidirectional causality between IgG N-glycans and SASP, which might reveal potential regulatory mechanisms.

MiR-24-3p enhances the Treg/Th17 balance to improve cerebral ischemic injury by suppressing acetyl-CoA carboxylase 1 expression

BACKGROUND

Targeting ACC1 (acetyl coenzyme A carboxylase 1) to restore the balance between T-helper 17 (Th17) cells and regulatory T cells (Tregs) through metabolic reprogramming has emerged as a promising strategy for reducing neuroinflammation following stroke. We examined the roles of potential miRNAs in regulating ACC1 expression in Tregs and treating ischemic stroke.

METHODS

The expression of miR-24-3p in CD4+T cells of mice was confirmed. Then the protective effects of Ago-24-3p in a mouse model of prolonged occlusion of the distal middle cerebral artery (dMCAO) were examined. We analyzed the infiltration of Tregs and CD3+T cells into the brain and evaluated the improvement of neurological deficits induced by Ago-24-3p using the Modified Garcia Score and foot fault testing.

RESULTS

Our investigation revealed that miR-24-3p specifically targets ACC1. Elevated levels of miR-24-3p have been demonstrated to increase the population of Tregs and enhance their proliferation and suppressive capabilities. Conversely, targeted reduction of ACC1 in CD4+T cells has been shown to counteract the improved functionality of Tregs induced by miR-24-3p. In a murine model of dMCAO, administration of Ago-24-3p resulted in a substantial reduction in the size of the infarct within the ischemic brain area. This effect was accompanied by an upregulation of Tregs and a downregulation of CD3+T cells in the ischemic brain region. In ACC1 conditional knockout mice, the ability of Ago-24-3p to enhance infiltrating Treg cells and diminish CD3+T cells in the ischemic brain area has been negated. Furthermore, its capacity to reduce infarct volume has been reversed. Furthermore, we demonstrated that Ago-24-3p sustained improvement in post-stroke neurological deficits for up to 4 weeks after the MCAO procedure.

CONCLUSIONS

MiR-24-3p shows promise in the potential to reduce ACC1 expression, enhance the immunosuppressive activity of Tregs, and alleviate injuries caused by ischemic stroke. These discoveries imply that miR-24-3p could be a valuable therapeutic option for treating ischemic stroke.

The association between plasma IgG N-glycosylation and neonatal hypoxic-ischemic encephalopathy: a case-control study

Introduction

Hypoxic-ischemic encephalopathy (HIE) is one of severe neonatal brain injuries, resulting from inflammation and the immune response after perinatal hypoxia and ischemia. IgG N-glycosylation plays a crucial role in various inflammatory diseases through mediating the balance between anti-inflammatory and pro-inflammatory responses. This study aimed to explore the effect of IgG N-glycosylation on the development of HIE.

Methods

This case-control study included 53 HIE patients and 57 control neonates. An ultrahigh-performance liquid chromatography (UPLC) method was used to determine the features of the plasma IgG N-glycans, by which 24 initial glycan peaks (GPs) were quantified. Multivariate logistic regression was used to examine the association between initial glycans and HIE, by which the significant parameters were used to develop a diagnostic model. Though receiver operating characteristic (ROC) curves, area under the curve (AUC) and 95% confidence interval (CI) were calculated to assess the performance of the diagnostic model.

Results

There were significant differences in 11 initial glycans between the patient and control groups. The levels of fucosylated and galactosylated glycans were significantly lower in HIE patients than in control individuals, while sialylated glycans were higher in HIE patients (p < 0.05). A prediction model was developed using three initial IgG N-glycans and fetal distress, low birth weight, and globulin. The ROC analysis showed that this model was able to discriminate between HIE patients and healthy individuals [AUC = 0.798, 95% CI: (0.716-0.880)].

Discussion

IgG N-glycosylation may play a role in the pathogenesis of HIE. Plasma IgG N-glycans are potential noninvasive biomarkers for screening individuals at high risk of HIE.

Glycosylation: A new signaling paradigm for the neurovascular diseases

A wide range of life-threatening conditions with complicated pathogenesis involves neurovascular disorders encompassing Neurovascular unit (NVU) damage. The pathophysiology of NVU is characterized by several features including tissue hypoxia, stimulation of inflammatory and angiogenic processes, and the initiation of intricate molecular interactions, collectively leading to an elevation in blood-brain barrier permeability, atherosclerosis and ultimately, neurovascular diseases. The presence of compelling data about the significant involvement of the glycosylation in the development of diseases has sparked a discussion on whether the abnormal glycosylation may serve as a causal factor for neurovascular disorders, rather than being just recruited as a secondary player in regulating the critical events during the development processes like embryo growth and angiogenesis. An essential tool for both developing new anti-ischemic therapies and understanding the processes of ischemic brain damage is undertaking pre-clinical studies of neurovascular disorders. Together with the post-translational modification of proteins, the modulation of glycosylation and its enzymes implicates itself in several abnormal activities which are known to accelerate neuronal vasculopathy. Despite the failure of the majority of glycosylation-based preclinical and clinical studies over the past years, there is a significant probability to provide neuroprotection utilizing modern and advanced approaches to target abnormal glycosylation activity at embryonic stages as well. This article focuses on a variety of experimental evidence to postulate the interconnection between glycosylation and vascular disorders along with possible treatment options.

IgG glycans in health and disease: Prediction, intervention, prognosis, and therapy

Immunoglobulin (IgG) glycosylation is a complex enzymatically controlled process, essential for the structure and function of IgG. IgG glycome is relatively stable in the state of homeostasis, yet its alterations have been associated with aging, pollution and toxic exposure, as well as various diseases, including autoimmune and inflammatory diseases, cardiometabolic diseases, infectious diseases and cancer. IgG is also an effector molecule directly involved in the inflammation processes included in the pathogenesis of many diseases. Numerous recently published studies support the idea that IgG N-glycosylation fine-tunes the immune response and plays a significant role in chronic inflammation. This makes it a promising novel biomarker of biological age, and a prognostic, diagnostic and treatment evaluation tool. Here we provide an overview of the current state of knowledge regarding the IgG glycosylation in health and disease, and its potential applications in pro-active prevention and monitoring of various health interventions.

GWAS of random glucose in 476,326 individuals provide insights into diabetes pathophysiology, complications and treatment stratification

Conventional measurements of fasting and postprandial blood glucose levels investigated in genome-wide association studies (GWAS) cannot capture the effects of DNA variability on 'around the clock' glucoregulatory processes. Here we show that GWAS meta-analysis of glucose measurements under nonstandardized conditions (random glucose (RG)) in 476,326 individuals of diverse ancestries and without diabetes enables locus discovery and innovative pathophysiological observations. We discovered 120 RG loci represented by 150 distinct signals, including 13 with sex-dimorphic effects, two cross-ancestry and seven rare frequency signals. Of these, 44 loci are new for glycemic traits. Regulatory, glycosylation and metagenomic annotations highlight ileum and colon tissues, indicating an underappreciated role of the gastrointestinal tract in controlling blood glucose. Functional follow-up and molecular dynamics simulations of lower frequency coding variants in glucagon-like peptide-1 receptor (GLP1R), a type 2 diabetes treatment target, reveal that optimal selection of GLP-1R agonist therapy will benefit from tailored genetic stratification. We also provide evidence from Mendelian randomization that lung function is modulated by blood glucose and that pulmonary dysfunction is a diabetes complication. Our investigation yields new insights into the biology of glucose regulation, diabetes complications and pathways for treatment stratification.

Human Plasma IgG N-Glycome Profiles Reveal a Proinflammatory Phenotype in Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

The pathological mechanism of chronic thromboembolic pulmonary hypertension (CTEPH) is not fully understood, and inflammation has been reported to be one of its etiological factors. IgG regulates systemic inflammatory homeostasis, primarily through its N-glycans. Little is known about IgG N-glycosylation in CTEPH. We aimed to map the IgG N-glycome of CTEPH to provide new insights into its pathogenesis and discover novel markers and therapies.

METHODS

We characterized the plasma IgG N-glycome of patients with CTEPH in a discovery cohort and validated our results in an independent validation cohort using matrix-assisted laser desorption/ionization time of flight mass spectrometry. Thereafter, we correlated IgG N-glycans with clinical parameters and circulating inflammatory cytokines in patients with CTEPH. Furthermore, we determined IgG N-glycan quantitative trait loci in CTEPH to reveal partial mechanisms underlying glycan changes.

RESULTS

Decreased IgG galactosylation representing a proinflammatory phenotype was found in CTEPH. The distribution of IgG galactosylation showed a strong association with NT-proBNP (N-terminal pro-B-type natriuretic peptide) in CTEPH. In line with the glycomic findings, IgG pro-/anti-inflammatory N-glycans correlated well with a series of inflammatory markers and gene loci that have been reported to be involved in the regulation of these glycans or inflammatory immune responses.

CONCLUSIONS

This is the first study to reveal the full signature of the IgG N-glycome of a proinflammatory phenotype and the genes involved in its regulation in CTEPH. Plasma IgG galactosylation may be useful for evaluating the inflammatory state in patients with CTEPH; however, this requires further validation. This study improves our understanding of the mechanisms underlying CTEPH inflammation from the perspective of glycomics.

Unravelling the genetic causality of immunoglobulin G N-glycans in ischemic stroke

BACKGROUND

Evidence suggests that immunoglobulin G (IgG) N-glycosylation is associated with ischemic stroke (IS). However, the causality of IgG N-glycosylation for IS remains unknown.

METHODS

Two-sample Mendelian randomization (MR) analyses were performed to investigate the potential causal effects of genetically determined IgG N-glycans on IS using publicly available summarized genetic data from East Asian and European populations. Genetic instruments were used as proxies for IgG N-glycan traits. IgG N-glycans were analysed using ultra-performance liquid chromatography. Four complementary MR methods were performed, including the inverse variance weighted method (IVW), MR‒Egger, weighted median and penalized weighted median. Furthermore, to further test the robustness of the results, MR based on Bayesian model averaging (MR-BMA) was then applied to select and prioritize IgG N-glycan traits as risk factors for IS.

RESULTS

After correcting for multiple testing, in two-sample MR analyses, genetically predicted IgG N-glycans were unrelated to IS in both East Asian and European populations, and the results remained consistent and robust in the sensitivity analysis. Moreover, MR-BMA also showed consistent results in both East Asian and European populations.

CONCLUSIONS

Contrary to observational studies, the study did not provide enough genetic evidence to support the causal associations of genetically predicted IgG N-glycan traits and IS, suggesting that N-glycosylation of IgG might not directly involve in the pathogenesis of IS.

The role of protein glycosylation in the occurrence and outcome of acute ischemic stroke

Acute ischemic stroke (AIS) is a serious and life-threatening disease worldwide. Despite thrombolysis or endovascular thrombectomy, a sizeable fraction of patients with AIS have adverse clinical outcomes. In addition, existing secondary prevention strategies with antiplatelet and anticoagulant drugs therapy are not able to adequately decrease the risk of ischemic stroke recurrence. Thus, exploring novel mechanisms for doing so represents an urgent need for the prevention and treatment of AIS. Recent studies have discovered that protein glycosylation plays a critical role in the occurrence and outcome of AIS. As a common co- and post-translational modification, protein glycosylation participates in a wide variety of physiological and pathological processes by regulating the activity and function of proteins or enzymes. Protein glycosylation is involved in two causes of cerebral emboli in ischemic stroke: atherosclerosis and atrial fibrillation. Following ischemic stroke, the level of brain protein glycosylation becomes dynamically regulated, which significantly affects stroke outcome through influencing inflammatory response, excitotoxicity, neuronal apoptosis, and blood-brain barrier disruption. Drugs targeting glycosylation in the occurrence and progression of stroke may represent a novel therapeutic idea. In this review, we focus on possible perspectives about how glycosylation affects the occurrence and outcome of AIS. We then propose the potential of glycosylation as a therapeutic drug target and prognostic marker for AIS patients in the future.

Association of IgG N-glycomics with prevalent and incident type 2 diabetes mellitus from the paradigm of predictive, preventive, and personalized medicine standpoint

Objectives

Type 2 diabetes mellitus (T2DM), a major metabolic disorder, is expanding at a rapidly rising worldwide prevalence and has emerged as one of the most common chronic diseases. Suboptimal health status (SHS) is considered a reversible intermediate state between health and diagnosable disease. We hypothesized that the time frame between the onset of SHS and the clinical manifestation of T2DM is the operational area for the application of reliable risk assessment tools, such as immunoglobulin G (IgG) N-glycans. From the viewpoint of predictive, preventive, and personalized medicine (PPPM/3PM), the early detection of SHS and dynamic monitoring by glycan biomarkers could provide a window of opportunity for targeted prevention and personalized treatment of T2DM.

Methods

Case-control and nested case-control studies were performed and consisted of 138 and 308 participants, respectively. The IgG N-glycan profiles of all plasma samples were detected by an ultra-performance liquid chromatography instrument.

Results

After adjustment for confounders, 22, five, and three IgG N-glycan traits were significantly associated with T2DM in the case-control setting, baseline SHS, and baseline optimal health participants from the nested case-control setting, respectively. Adding the IgG N-glycans to the clinical trait models, the average area under the receiver operating characteristic curves (AUCs) of the combined models based on repeated 400 times fivefold cross-validation differentiating T2DM from healthy individuals were 0.807 in the case-control setting and 0.563, 0.645, and 0.604 in the pooled samples, baseline SHS, and baseline optimal health samples of nested case-control setting, respectively, which presented moderate discriminative ability and were generally better than models with either glycans or clinical features alone.

Conclusions

This study comprehensively illustrated that the observed altered IgG N-glycosylation, i.e., decreased galactosylation and fucosylation/sialylation without bisecting GlcNAc, as well as increased galactosylation and fucosylation/sialylation with bisecting GlcNAc, reflects a pro-inflammatory state of T2DM. SHS is an important window period of early intervention for individuals at risk for T2DM; glycomic biosignatures as dynamic biomarkers have the ability to identify populations at risk for T2DM early, and the combination of evidence could provide suggestive ideas and valuable insight for the PPPM of T2DM.

Supplementary information

The online version contains supplementary material available at 10.1007/s13167-022-00311-3.

Immunoglobulin G N-glycan, inflammation and type 2 diabetes in East Asian and European populations: a Mendelian randomization study

Background

Immunoglobulin G (IgG) N-glycans have been shown to be associated with the risk of type 2 diabetes (T2D) and its risk factors. However, whether these associations reflect causal effects remain unclear. Furthermore, the associations of IgG N-glycans and inflammation are not fully understood.

Methods

We examined the causal associations of IgG N-glycans with inflammation (C-reactive protein (CRP) and fibrinogen) and T2D using two-sample Mendelian randomization (MR) analysis in East Asian and European populations. Genetic variants from IgG N-glycan quantitative trait loci (QTL) data were used as instrumental variables. Two-sample MR was conducted for IgG N-glycans with inflammation (75,391 and 18,348 participants of CRP and fibrinogen in the East Asian population, 204,402 participants of CRP in the European population) and T2D risk (77,418 cases and 356,122 controls of East Asian ancestry, 81,412 cases and 370,832 controls of European ancestry).

Results

After correcting for multiple testing, in the East Asian population, genetically determined IgG N-glycans were associated with a higher risk of T2D, the odds ratios (ORs) were 1.009 for T2D per 1- standard deviation (SD) higher GP5, 95% CI = 1.003–1.015; P = 0.0019; and 1.013 for T2D per 1-SD higher GP13, 95% CI = 1.006–1.021; P = 0.0005. In the European population, genetically determined decreased GP9 was associated with T2D (OR = 0.899 per 1-SD lower GP9, 95% CI: 0.845–0.957). In addition, there was suggestive evidence that genetically determined IgG N-glycans were associated with CRP in both East Asian and European populations after correcting for multiple testing, but no associations were found between IgG N-glycans and fibrinogen. There was limited evidence of heterogeneity and pleiotropy bias.

Conclusions

Our results provided novel genetic evidence that IgG N-glycans are causally associated with T2D.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00543-z.

Identification of Differentially Expressed microRNAs Associated with Ischemic Stroke by Integrated Bioinformatics Approaches

Ischemic stroke (IS) is one of the leading causes of disability and mortality worldwide. This study aims to find the crucial exosomal miRNAs associated with IS by using bioinformatics methods, reveal potential biomarkers for IS, and investigate the association between the identified biomarker and immune cell pattern in the peripheral blood of IS patients. In this study, 3 up-regulated miRNAs (hsa-miR-15b-5p, hsa-miR-184, and hsa-miR-16-5p) miRNAs in the serum exosomes between IS patients and healthy controls from GEO database (GSE199942) and 25 down-regulated genes of peripheral blood mononuclear cells of IS patients from GSE22255 were obtained with the help of the R software. GO annotation and KEGG pathway enrichment analysis showed that the 25 down-regulated genes were associated with coenzyme metabolic process and were mainly enriched in the N-glycan biosynthesis pathway. Furthermore, we performed the LASSO algorithm to narrow down the above 25 intersected genes, and identified 8 key genes which had a good diagnostic value in discriminating IS patients from the healthy controls analyzed with ROC curve. CIBERSORT algorithm indicated that the abundance of M0 macrophages and resting mast cells was significantly lower than that of the control group. The spearman correlation analysis showed that STT3A was negatively correlated with the proportion of follicular helper T cells, activated NK cells and resting dendritic cells. Finally, GSE117064 showed that has-miR-16-5p was more advantageous for diagnosing stroke. In conclusion, hsa-miR-15b-5p, hsa-miR-184, and hsa-miR-16-5p are identified as specific related exosomal miRNAs for IS patients. These genes may provide new targets for the early identification of IS.

Translation and cross-cultural validation of a precision health tool, the Suboptimal Health Status Questionnaire-25, in Korean

BACKGROUND

Suboptimal health status (SHS) is a reversible stage between health and illness that is characterized by health complaints, low energy, general weakness, and chronic fatigue. The Suboptimal Health Status Questionnaire-25 (SHSQ-25) has been validated in three major populations (African, Asian, and Caucasian) and is internationally recognized as a reliable and robust tool for health estimation in general populations. This study focused on the development of K-SHSQ-25, a Korean version of the SHSQ-25, from its English version.

METHODS

The SHSQ-25 was translated from English to Korean according to international guidelines set forth by the World Health Organization (WHO) for health instrument translation between different languages. A subsequent cross-sectional survey involved 460 healthy South Korean participants (aged 18-83 years; 65.4% females) to answer the 25 questions focusing on the health perspectives of 5 domains, 1) fatigue, 2) cardiovascular health, 3) digestive tract, 4) immune system and 5) mental health. The K-SHSQ-25 was further validated using tests for reliability, internal consistency, exploratory factor analysis (EFA), and confirmatory factor analysis (CFA).

RESULTS

The version of K-SHSQ-25 achieved linguistic, cultural, and conceptual equivalence to the English version. The intraclass correlation coefficient (ICC) of test-retest reliability for individual items ranged from 0.88 to 0.99. Reliability estimates based on internal consistency reached a Cronbach's α of 0.953; the Cronbach's α for each domain ranged from 0.76 to 0.94. Regarding construct validity, the EFA of the K-SHSQ-25 generally replicated the multidimensional structure (fatigue, cardiovascular, digestive, immune system, and mental health) and 25 questions. The CFA revealed that the root mean square error of approximation (RMSEA), goodness-of-fit index (GFI) and adjusted goodness of fit index (AGFI) were excellent (RMSEA = 0.069<0.08, GFI = 0.929>0.90, AGFI = 0.907>0.90). The five domains of the K-SHSQ-25 showed significant correlations with each other (r = 0.59-0.81, P<0.001). The cut-off point of K-SHSQ-25 for SHS was determined as an SHS score of 25. The prevalence of SHS in this study was 60.0% (276/460), with 47.8% (76/159) for males and 58.5% for females (176/301).

CONCLUSIONS

Our results indicate that the Korean version of SHSQ-25, K-SHSQ-25, is a transcultural equivalent, robust, valid, and reliable assessment tool for evaluating SHS in the Korean-speaking population.

Thirty-six months recurrence after acute ischemic stroke among patients with comorbid type 2 diabetes: A nested case-control study

BACKGROUND

Stroke patients have to face a high risk of recurrence, especially for those with comorbid T2DM, which usually lead to much more serious neurologic damage and an increased likelihood of death. This study aimed to explore determinants of stroke relapse among patients with comorbid T2DM.

MATERIALS AND METHODS

We conducted this case-control study nested a prospective cohort of ischemic stroke (IS) with comorbid T2DM. During 36-month follow-up, the second stroke occurred in 84 diabetic IS patients who were allocated into the case group, while 613 patients without recurrence were the controls. We collected the demographic data, behaviors and habits, therapies, and family history at baseline, and measured the variables during follow-up. LASSO and Logistic regression analyses were carried out to develop a prediction model of stroke recurrence. The receiver operator characteristic (ROC) curve was employed to evaluate the performance of the prediction model.

RESULTS

Compared to participants without recurrence, the higher levels of pulse rate (78.29 ± 12.79 vs. 74.88 ± 10.93) and hypertension (72.6 vs. 61.2%) were recorded at baseline. Moreover, a lower level of physical activity (77.4 vs. 90.4%), as well as a higher proportion of hypoglycemic therapy (36.9 vs. 23.3%) was also observed during 36-month follow-up. Multivariate logistic regression revealed that higher pulse rate at admission (OR = 1.027, 95 %CI = 1.005-1.049), lacking physical activity (OR = 2.838, 95% CI = 1.418-5.620) and not receiving hypoglycemic therapy (OR = 1.697, 95% CI = 1.013-2.843) during follow-up increased the risk of stroke recurrence. We developed a prediction model using baseline pulse rate, hypoglycemic therapy, and physical activity, which produced an area under ROC curve (AUC) of 0.689.

CONCLUSION

Physical activity and hypoglycemic therapy play a protective role for IS patients with comorbid diabetes. In addition to targeted therapeutics, the improvement of daily-life habit contributes to slowing the progress of the IS.

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.

Acute Ischemic Stroke Comorbid with Type 2 Diabetes: Long-Term Prognosis Determinants in a 36-Month Prospective Study for Personalized Medicine

Ischemic stroke (IS) is often comorbid with type 2 diabetes mellitus (T2DM) wherein the determinants of long-term outcomes, beyond the acute stroke phase, are not adequately known. This study identified the determinants of long-term outcomes for diabetic IS patients through a prospective nested case-control study in 624 patients treated with conservative measures (38.60% females, mean age: 63.85 years). After 36-month follow-up, 117 (18.8%) patients with poor outcome were enrolled in the case group. The poor outcome was defined with a modified Rankin Scale (mRS) score ≥3. Meanwhile, 374 (59.9%) patients with good outcome, defined as (mRS score <3), were included in the control group. Patients who died (n = 32) or lost to follow-up (n = 101) were excluded in analysis. Poor prognostic outcome was positively associated with (1) the pulse rate at admission, (2) diastolic blood pressure (DBP), and (3) fasting blood glucose (FBG) during follow-up, whereas physical activity and lipid-lowering treatment during follow-up were negatively associated. Importantly, a forecasting model with these indicators distinguished the patients with good versus poor outcomes with 70.1% sensitivity and 73.5% specificity. Health care professionals and laboratory medicine scholars may want to monitor an increase in DBP and FBG during follow-up, as well as physical activity and lipid-lowering treatment, in relationship to the prognosis of IS with comorbid T2DM after conservative therapies. The proposed predictive model for personalized/precision medicine requires field testing in independent studies, and might help risk stratification with theranostic tests for patients with acute IS who also have a diagnosis of T2DM.

Association of immunoglobulin G N-glycosylation with carotid atherosclerotic plaque phenotypes and actual clinical cardiovascular events: a study protocol for a longitudinal prospective cohort study

INTRODUCTION

Immune-inflammatory response plays a key role in the pathogenesis of atherosclerosis. IgG N-glycosylation is reported to be associated with the 10-year atherosclerotic cardiovascular disease risk score and subclinical atherosclerosis. However, the relationship of IgG glycosylation with actual clinical cardiovascular disease (CVD) events and plaque phenotypes has rarely been investigated. Therefore, this study aims to understand whether IgG glycosylation traits are correlated with actual clinical CVD events and plaque phenotypes.

METHODS AND ANALYSIS

Designed to verify the efficacy of IgG glycosylation as a risk for CVD events and screen potential biomarkers of CVD to prevent atherosclerosis occurrence, this longitudinal prospective cohort study will be conducted at the First Affiliated Hospital of Shantou University Medical College, China. In total, 2720 participants routinely examined by carotid ultrasound will be divided into different groups according to plaque phenotype characteristics. Ultra-performance liquid chromatography will be performed to separate and detect IgG N-glycans in serum collected at baseline and at the end of the first, second and third years. The primary outcome is the actual clinical CVD composite events, including non-fatal myocardial infarction, death due to coronary heart disease, and fatal or non-fatal stroke.

ETHICS AND DISSEMINATION

The Clinical Ethics Committee of the First Affiliated Hospital of Shantou University Medical College approved this study (number: B-2021-127). Findings of this study will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR2100048740.

Genome-Wide Mapping of Plasma IgG N-Glycan Quantitative Trait Loci Identifies a Potentially Causal Association between IgG N-Glycans and Rheumatoid Arthritis

Observational studies highlight associations of IgG N-glycosylation with rheumatoid arthritis (RA); however, the causality between these conditions remains to be determined. Standard and multivariable two-sample Mendelian randomization (MR) analyses integrating a summary genome-wide association study for RA and IgG N-glycan quantitative trait loci (IgG N-glycan-QTL) data were performed to explore the potentially causal associations of IgG N-glycosylation with RA. After correcting for multiple testing (p < 2 × 10^-3), the standard MR analysis based on the inverse-variance weighted method showed a significant association of genetically instrumented IgG N-glycan (GP4) with RA (odds ratio_GP4 = 0.906, 95% confidence interval = 0.857-0.958, p = 5.246 × 10^-4). In addition, we identified seven significant associations of genetically instrumented IgG N-glycans with RA by multivariable MR analysis (p < 2 × 10^-3). Results were broadly consistent in sensitivity analyses using MR_Lasso, MR_weighted median, MR_Egger regression, and leave-one-out analysis with different instruments (all p values <0.05). There was limited evidence of pleiotropy bias (all p values > 0.05). In conclusion, our MR analysis incorporating genome-wide association studies and IgG N-glycan-QTL data revealed that IgG N-glycans were potentially causally associated with RA. Our findings shed light on the role of IgG N-glycosylation in the development of RA. Future studies are needed to validate our findings and to explore the underlying physiological mechanisms in the etiology of RA.

Rapid triage for ischemic stroke: a machine learning-driven approach in the context of predictive, preventive and personalised medicine

BACKGROUND

Recognising the early signs of ischemic stroke (IS) in emergency settings has been challenging. Machine learning (ML), a robust tool for predictive, preventive and personalised medicine (PPPM/3PM), presents a possible solution for this issue and produces accurate predictions for real-time data processing.

METHODS

This investigation evaluated 4999 IS patients among a total of 10,476 adults included in the initial dataset, and 1076 IS subjects among 3935 participants in the external validation dataset. Six ML-based models for the prediction of IS were trained on the initial dataset of 10,476 participants (split participants into a training set [80%] and an internal validation set [20%]). Selected clinical laboratory features routinely assessed at admission were used to inform the models. Model performance was mainly evaluated by the area under the receiver operating characteristic (AUC) curve. Additional techniques-permutation feature importance (PFI), local interpretable model-agnostic explanations (LIME), and SHapley Additive exPlanations (SHAP)-were applied for explaining the black-box ML models.

RESULTS

Fifteen routine haematological and biochemical features were selected to establish ML-based models for the prediction of IS. The XGBoost-based model achieved the highest predictive performance, reaching AUCs of 0.91 (0.90-0.92) and 0.92 (0.91-0.93) in the internal and external datasets respectively. PFI globally revealed that demographic feature age, routine haematological parameters, haemoglobin and neutrophil count, and biochemical analytes total protein and high-density lipoprotein cholesterol were more influential on the model's prediction. LIME and SHAP showed similar local feature attribution explanations.

CONCLUSION

In the context of PPPM/3PM, we used the selected predictors obtained from the results of common blood tests to develop and validate ML-based models for the diagnosis of IS. The XGBoost-based model offers the most accurate prediction. By incorporating the individualised patient profile, this prediction tool is simple and quick to administer. This is promising to support subjective decision making in resource-limited settings or primary care, thereby shortening the time window for the treatment, and improving outcomes after IS.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13167-022-00283-4.

Association Between Immunoglobulin G N-glycosylation and Vascular Cognitive Impairment in a Sample With Atherosclerosis: A Case-Control Study

Background

Atherosclerosis is considered a crucial component in the pathogenesis of decreased cognitive function, as occurs in vascular cognitive impairment (VCI). Inflammation and the immune response play a significant role in the development of many chronic diseases. Immunoglobulin G (IgG) N-glycosylation has been implicated in the development of a variety of diseases by affecting the anti-inflammatory and proinflammatory responses of IgG. This study aimed to investigate the association between IgG N-glycosylation and VCI in a sample of patients with atherosclerosis through a case-control study.

Method

We recruited a total of 330 patients with atherosclerosis to participate in this case-control study, including 165 VCI patients and 165 sex- and age-matched participants with normal cognitive function. The plasma IgG N-glycans of participants were separated by ultrahigh-performance liquid chromatography. An enzyme-linked immunosorbent assay (ELISA) kit was used to determine the corresponding serum inflammatory factors. Atherosclerosis was diagnosed by carotid ultrasound, and the diagnosis of VCI was based on the “Guidelines for the Diagnosis and Treatment of Vascular Cognitive Impairment in China (2019)”. A multivariate logistic regression model was used to explore the association between IgG N-glycans and VCI. We also analyzed the relationship between IgG N-glycans and the inflammatory state of VCI through canonical correlation analysis (CCA).

Results

Through the multivariate logistic regression analysis, 8 glycans and 13 derived traits reflecting decreased sialylation and galactosylation and increased bisecting GlcNAc significantly differed between the case and control groups after adjusting for confounding factors (P < 0.05, q < 0.05). Similarly, the differences in TNF-α, IL-6, and IL-10 were statistically significant between the case and control groups after adjusting for the effects of confounding factors (P < 0.05, q < 0.05). The CCA results showed that VCI-related initial N-glycans were significantly correlated with VCI-related inflammatory factors (r = 0.272, P = 0.004). The combined AUC value (AUC_combined = 0.885) of 7 initial glycans and inflammatory factors was higher than their respective values (AUC_{initial glycans} = 0.818, AUC_{inflammatory factors} = 0.773).

Conclusion

The findings indicate that decreased sialylation and galactosylation and increased bisecting GlcNAc reflected by IgG N-glycans might affect the occurrence of VCI in patients with atherosclerosis though promoting the proinflammatory function of IgG. IgG N-glycans may serve as potential biomarkers to distinguish VCI in individuals with atherosclerosis.

All around suboptimal health - a joint position paper of the Suboptimal Health Study Consortium and European Association for Predictive, Preventive and Personalised Medicine

First two decades of the twenty-first century are characterised by epidemics of non-communicable diseases such as many hundreds of millions of patients diagnosed with cardiovascular diseases and the type 2 diabetes mellitus, breast, lung, liver and prostate malignancies, neurological, sleep, mood and eye disorders, amongst others. Consequent socio-economic burden is tremendous. Unprecedented decrease in age of maladaptive individuals has been reported. The absolute majority of expanding non-communicable disorders carry a chronic character, over a couple of years progressing from reversible suboptimal health conditions to irreversible severe pathologies and cascading collateral complications. The time-frame between onset of SHS and clinical manifestation of associated disorders is the operational area for an application of reliable risk assessment tools and predictive diagnostics followed by the cost-effective targeted prevention and treatments tailored to the person. This article demonstrates advanced strategies in bio/medical sciences and healthcare focused on suboptimal health conditions in the frame-work of Predictive, Preventive and Personalised Medicine (3PM/PPPM). Potential benefits in healthcare systems and for society at large include but are not restricted to an improved life-quality of major populations and socio-economical groups, advanced professionalism of healthcare-givers and sustainable healthcare economy. Amongst others, following medical areas are proposed to strongly benefit from PPPM strategies applied to the identification and treatment of suboptimal health conditions:Stress overload associated pathologiesMale and female healthPlanned pregnanciesPeriodontal healthEye disordersInflammatory disorders, wound healing and pain management with associated complicationsMetabolic disorders and suboptimal body weightCardiovascular pathologiesCancersStroke, particularly of unknown aetiology and in young individualsSleep medicineSports medicineImproved individual outcomes under pandemic conditions such as COVID-19.

IgG N-glycans

Glycosylation, one of the most common post-translational modifications in mammalian cells, impacts many biological processes such as cell adhesion, proliferation and differentiation. As the most abundant glycoprotein in human serum, immunoglobulin G (IgG) plays a vital role in immune response and protection. There is a growing body of evidence suggests that IgG structure and function are modulated by attached glycans, especially N-glycans, and aberrant glycosylation is associated with disease states. In this chapter, we review IgG glycan repertoire and function, strategies for profiling IgG N-glycome and recent studies. Mass spectrometry (MS) based techniques are the most powerful tools for profiling IgG glycome. IgG glycans can be divided into high-mannose, biantennary complex and hybrid types, modified with mannosylation, core-fucosylation, galactosylation, bisecting GlcNAcylation, or sialylation. Glycosylation of IgG affects antibody half-life and their affinity and avidity for antigens, regulates crystallizable fragment (Fc) structure and Fcγ receptor signaling, as well as antibody effector function. Because of their critical roles, IgG N-glycans appear to be promising biomarkers for various disease states. Specific IgG glycosylation can convert a pro-inflammatory response to an anti-inflammatory activity. Accordingly, IgG glycoengineering provides a powerful approach to potentially develop effective drugs and treat disease. Based on the understanding of the functional role of IgG glycans, the development of vaccines with enhanced capacity and long-term protection are possible in the near future.

Heritability Enrichment of Immunoglobulin G N-Glycosylation in Specific Tissues

Genome-wide association studies (GWAS) have identified over 60 genetic loci associated with immunoglobulin G (IgG) N-glycosylation; however, the causal genes and their abundance in relevant tissues are uncertain. Leveraging data from GWAS summary statistics for 8,090 Europeans, and large-scale expression quantitative trait loci (eQTL) data from the genotype-tissue expression of 53 types of tissues (GTEx v7), we derived a linkage disequilibrium score for the specific expression of genes (LDSC-SEG) and conducted a transcriptome-wide association study (TWAS). We identified 55 gene associations whose predicted levels of expression were significantly associated with IgG N-glycosylation in 14 tissues. Three working scenarios, i.e., tissue-specific, pleiotropic, and coassociated, were observed for candidate genetic predisposition affecting IgG N-glycosylation traits. Furthermore, pathway enrichment showed several IgG N-glycosylation-related pathways, such as asparagine N-linked glycosylation, N-glycan biosynthesis and transport to the Golgi and subsequent modification. Through phenome-wide association studies (PheWAS), most genetic variants underlying TWAS hits were found to be correlated with health measures (height, waist-hip ratio, systolic blood pressure) and diseases, such as systemic lupus erythematosus, inflammatory bowel disease, and Parkinson's disease, which are related to IgG N-glycosylation. Our study provides an atlas of genetic regulatory loci and their target genes within functionally relevant tissues, for further studies on the mechanisms of IgG N-glycosylation and its related diseases.

The Rapidly Expanding Nexus of Immunoglobulin G N-Glycomics, Suboptimal Health Status, and Precision Medicine

Immunoglobulin G is a prevalent glycoprotein, whose downstream immune responses are partially mediated by the N-glycans within the fragment crystallisable domain. Collectively termed the N-glycome, it is considered a complex intermediate phenotype: an amalgamation of genetic predisposition, environmental exposure, and health behaviours over the life-course. Thus, the immunoglobulin G N-glycome may provide an indication of health status on the spectrum from health to disease and infirmary. Although variability exists within and between populations, composition of the immunoglobulin G N-glycome remains stable over short periods of time. This underscores the potential of harnessing the immunoglobulin G N-glycome as an ideal tool for preclinical disease risk prediction, stratification, and prognosis through the development of precise dynamic biomarkers.

Glycosylation and Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide, accounting for approximately 18 million deaths in 2017. Coronary artery disease is the predominant cause of death from CVD, followed by stroke. Owing to recent technological advancements, glycans and glycosylation patterns of proteins have been investigated in association with CVD risk factors and clinical events. These studies have found significant associations of glycans as biomarkers of systemic inflammation and major CVD risk factors and events. While more limited, studies have also shown that glycans may be useful for monitoring response to anti-inflammatory therapies and may be responsive to changes in lifestyle, particularly in patients with chronic inflammatory diseases. Glycans capture summative risk information related to inflammatory, immune, and signaling pathways and are promising biomarkers for CVD risk prediction and therapeutic monitoring.

The effect of n-3 polyunsaturated fatty acids enriched hen eggs consumption on IgG and total plasma protein N-glycosylation in healthy individuals and cardiovascular patients

OBJECTIVE

This study determined the effect of n-3 PUFAs enriched hen eggs consumption on IgG and total plasma protein N-glycan profiles and inflammatory biomarkers level in healthy individuals (N = 33) and cardiovascular (CV) patients (N = 21).

MATERIALS AND METHODS

Subjects were divided to Control-Healthy and Control-CV subgroups (consumed three regular hens' eggs/daily (249 mg n-3 PUFAs/day)), and n-3-PUFAs-Healthy and n-3-PUFAs-CV subgroups (consumed three n-3 PUFAs enriched hen eggs/daily (1053 mg n-3 PUFAs/day)) for 3 weeks. Serum free fatty acids profile and high-sensitivity C reactive protein (hsCRP), interleukin 6 and 10 (IL-6, IL-10) and tumor necrosis factor alpha were measured. Total plasma protein and IgG N-glycome have been profiled before and after dietary protocols.

RESULTS

Serum n-3 PUFAs concentration significantly increased following n-3 PUFAs hen eggs consumption in both n-3-PUFAs-Healthy and n-3-PUFAs-CV. IL-10 significantly increased in both Healthy subgroups, while no change occurred in CV subgroups. Derived IgG N-glycan traits: bisecting GlcNAc (B) significantly decreased in n-3-PUFAs-Healthy, while agalactosylation (G0) and core fucosylation (CF) significantly increased in Control-Healthy. Derived total plasma protein N-glycan traits: high branching glycans (HB), trigalactosylation (G3), tetragalactosylation (G4), trisialylation (S3), tetrasialylation (S4) and antennary fucosylation (AF) significantly decreased, while G0, monogalactosylation (G1), neutral glycans (S0), B, CF and oligomannose structures (OM) significantly increased in n-3 PUFAs-CV. Digalactosylation (G2) significantly decreased, and G0, G1, S0, disialylation (S2), B and CF significantly increased in Control-CV.

CONCLUSIONS

n-3 PUFAs consumption alters IgG N-glycan traits and IL-10 in healthy individuals, and total plasma protein N-glycan traits in CV patients, by shifting them toward less inflammatory N-glycosylation profile.

Glycan Imaging Mass Spectrometry: Progress in Developing Clinical Diagnostic Assays for Tissues, Biofluids, and Cells

N-glycan imaging mass spectrometry (IMS) can rapidly and reproducibly identify changes in disease-associated N-linked glycosylation that are linked with histopathology features in standard formalin-fixed paraffin-embedded tissue samples. It can detect multiple N-glycans simultaneously and has been used to identify specific N-glycans and carbohydrate structural motifs as possible cancer biomarkers. Recent advancements in instrumentation and sample preparation are also discussed. The tissue N-glycan IMS workflow has been adapted to new glass slide-based assays for effective and rapid analysis of clinical biofluids, cultured cells, and immunoarray-captured glycoproteins for detection of changes in glycosylation associated with disease.

Dynamic changes in Beclin-1, LC3B and p62 at various time points in mice with temporary middle cerebral artery occlusion and reperfusion (tMCAO)

Ischaemic stroke is attributable to cerebrovascular disease and is associated with high morbidity, disability, mortality and recurrence. Autophagy is a critical mediator and plays dual roles in ischaemic stroke. Autophagy can protect against ischaemic brain injury during the early stage of ischaemic stroke, while excessive autophagy can induce apoptosis and exacerbate brain injury. However, the time-dependent variations in autophagy in ischaemic stroke are unknown. C57BL/6 mice were used to establish a model of temporary middle cerebral artery occlusion and reperfusion (tMCAO). The neurological functional scores and infarct volumes were determined at 1 d, 3 d, 5 d, and 7 d after modelling. The levels of Beclin-1, LC3B, p62, GFAP, TNF-α, IL-6, IL-10, ROS, 4-HNE and 8-OHDG were measured by ELISA, RT-PCR, immunofluorescence analysis and western blotting. The morphology of autophagosomes of ischaemic penumbra was observed by transmission electron microscopy (TEM). Beclin-1, LC3B, ROS, 4-HNE, 8-OHDG, GFAP, TNF-α and IL-6 levels increased (P < 0.01), while p62 and IL-10 levels decreased (P < 0.01) after tMCAO compared to those in the sham group. Beclin-1, LC3B, ROS, 4-HNE, 8-OHDG, GFAP, TNF-α and IL-6 levels were reduced in tMCAO mice at 3 d, 5 d and 7 d (P<0.05), and p62 and IL-10 levels were enhanced (P < 0.05) compared to those at 1 d. In addition, Beclin-1 positively correlated with LC3B, GFAP, TNF-α, IL-6, ROS, 4-HNE and 8-OHDG (P < 0.05), and Beclin-1 negatively correlated with p62 and IL-10 (P < 0.05). The number of autophagosomes was consistent with the expression of autophagy marker proteins, both showing a steady decrease. In summary, autophagy was activated within 7 d of tMCAO induction, and it strengthened at 1 d and then weakened steadily from 3 to 7 d. In addition, this study verified that autophagy positively correlated with the inflammatory response and oxidative stress at 7 d after tMCAO.

COVID-19 and Preparing Planetary Health for Future Ecological Crises: Hopes from Glycomics for Vaccine Innovation

A key lesson emerging from COVID-19 is that pandemic proofing planetary health against future ecological crises calls for systems science and preventive medicine innovations. With greater proximity of the human and animal natural habitats in the 21st century, it is also noteworthy that zoonotic infections such as COVID-19 that jump from animals to humans are increasingly plausible in the coming decades. In this context, glycomics technologies and the third alphabet of life, the sugar code, offer veritable prospects to move omics systems science from discovery to diverse applications of relevance to global public health and preventive medicine. In this expert review, we discuss the science of glycomics, its importance in vaccine development, and the recent progress toward discoveries on the sugar code that can help prevent future infectious outbreaks that are looming on the horizon in the 21st century. Glycomics offers veritable prospects to boost planetary health, not to mention the global scientific capacity for vaccine innovation against novel and existing infectious agents.

A simple lectin-based biochip might display the potential clinical value of glycomics in patients with spontaneous intracerebral hemorrhage

Background

Intracerebral hemorrhage (ICH) is a cerebrovascular disease with extremely high disability and mortality rates. Glycans play critical roles in biological processes. However, whether glycans can serve as potential biomarkers for determining clinical diagnosis and prognosis in ICH remains determined.

Methods

In this study, we established a lectin-biochip to measure serum glycans levels in ICH patients (n=48) and healthy controls (n=16). An enzyme-linked immunosorbent assay (ELISA) was carried out to determine serum levels of IL-10 and TNF-α in the patients. Correlation analyses of the serum glycan and cytokine levels and the clinicopathological parameters of patients were performed.

Results

The biochip-based data revealed that the serum levels of α-Man/α-Glc (ConA), Galβ3GalNAc (PNA), GalNAc (VVA), Fucα6GlcNAc (AAL), α-Fuc (LTL), and Galβ3GalNAc-Ser/Thr (AIL) significantly increased in the super-acute phase of ICH in comparison with healthy controls. Clinicopathological analysis indicated the serum levels of ConA, VVA, and LTL had significant associations with the National Institute of Health Stroke Scale (NIHSS), and serum VVA levels had a significant association with the Mini-Mental State Examination (MMSE) at day 90 after ICH. Correlation coefficient analysis revealed significant correlations between TNF-α and ConA (P<0.001) as well as between IL-10 and ConA (P<0.001), PNA (P=0.02), VVA (P<0.001), and MAL (P=0.04), respectively.

Conclusions

We established a proof-of-concept platform for detecting serum glycomics and highlighted their potential value in diagnosing and predicting ICH patients' outcomes.

Association of dementia with immunoglobulin G N-glycans in a Chinese Han Population

Immunoglobulin G (IgG) functionality can drastically change from anti- to proinflammatory by alterations in the IgG N-glycan patterns. Our previous studies have demonstrated that IgG N-glycans associated with the risk factors of dementia, such as aging, dyslipidemia, type 2 diabetes mellitus, hypertension, and ischemic stroke. Therefore, the aim is to investigate whether the effects of IgG N-glycan profiles on dementia exists in a Chinese Han population. A case–control study, including 81 patients with dementia, 81 age- and gender-matched controls with normal cognitive functioning (NC) and 108 non-matched controls with mild cognitive impairment (MCI) was performed. Plasma IgG N-glycans were separated by ultra-performance liquid chromatography. Fourteen glycan peaks reflecting decreased of sialylation and core fucosylation, and increased bisecting N-acetylglucosamine (GlcNAc) N-glycan structures were of statistically significant differences between dementia and NC groups after controlling for confounders (p < 0.05; q < 0.05). Similarly, the differences for these 14 initial glycans were statistically significant between AD and NC groups after adjusting for the effects of confounders (p < 0.05; q < 0.05). The area under the receiver operating curve (AUC) value of the model consisting of GP8, GP9, and GP14 was determined to distinguish dementia from NC group as 0.876 [95% confidence interval (CI): 0.815–0.923] and distinguish AD from NC group as 0.887 (95% CI: 0.819–0.936). Patients with dementia were of an elevated proinflammatory activity via the significant changes of IgG glycome. Therefore, IgG N-glycans might contribute to be potential novel biomarkers for the neurodegenerative process risk assessment of dementia.

Elastin-like hydrogel stimulates angiogenesis in a severe model of critical limb ischemia (CLI): An insight into the glyco-host response

Critical limb ischemia (CLI) is characterized by the impairment of microcirculation, necrosis and inflammation of the muscular tissue. Although the role of glycans in mediating inflammation has been reported, changes in the glycosylation following muscle ischemia remains poorly understood. Here, a murine CLI model was used to show the increase of high mannose, α-(2, 6)-sialic acid and the decrease of hybrid and bisected N-glycans as glycosylation associated with the ischemic environment. Using this model, the efficacy of an elastin-like recombinamers (ELR) hydrogel was assessed. The hydrogel modulates key angiogenic signaling pathways, resulting in capillary formation, and ECM remodeling. Arterioles formation, reduction of fibrosis and anti-inflammatory macrophage polarization wa also induced by the hydrogel administration. Modulation of glycosylation was observed, suggesting, in particular, a role for mannosylation and sialylation in the mediation of tissue repair. Our study elucidates the angiogenic potential of the ELR hydrogel for CLI applications and identifies glycosylation alterations as potential new therapeutic targets.

Immunoglobulin G Glycosylation in Diseases

Changes in immunoglobulin G (IgG) glycosylation pattern have been observed in a vast array of auto- and alloimmune, infectious, cardiometabolic, malignant, and other diseases. This chapter contains an updated catalog of over 140 studies within which IgG glycosylation analysis was performed in a disease setting. Since the composition of IgG glycans is known to modulate its effector functions, it is suggested that a changed IgG glycosylation pattern in patients might be involved in disease development and progression, representing a predisposition and/or a functional effector in disease pathology. In contrast to the glycopattern of bulk serum IgG, which likely relates to the systemic inflammatory background, the glycosylation profile of antigen-specific IgG probably plays a direct role in disease pathology in several infectious and allo- and autoimmune antibody-dependent diseases. Depending on the specifics of any given disease, IgG glycosylation read-out might therefore in the future be developed into a useful clinical biomarker or a supplementary to currently used biomarkers.

Glycosylation Profiling as a Biomarker of Suboptimal Health Status for Chronic Disease Stratification

WHO defines health as "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity." We coined and defined suboptimal health status (SHS) as a subclinical, reversible stage of the pre-chronic disease. SHS is a physical state between health and disease, characterized by health complaints, general weakness, chronic fatigue, and low energy levels. We have developed an instrument to measure SHS, Suboptimal Health Status Questionnaire-25 (SHSQ-25), a self-reported survey assessing five health components that has been validated in various ethnical populations. Our studies suggest that SHS is associated with the major components of cardiovascular health and the early onset of metabolic diseases. Besides subjective measure of health (SHS), glycans are conceived as objective biomarkers of SHS. Glycans are complex and branching carbohydrate moieties attached to proteins, participating in inflammatory regulation and chronic disease pathogenesis. We have been investigating the role of glycans and SHS in multiple cardiometabolic diseases in different ethnical populations (African, Chinese, and Caucasian). Here we present case studies to prove that a combination of subjective health measure (SHS) with objective health measure (glycans) represents a window of opportunity to halt or reverse the progression of chronic diseases.

Immunoglobulin G Glycosylation Changes in Aging and Other Inflammatory Conditions

Among the multiple roles played by protein glycosylation, the fine regulation of biological interactions is one of the most important. The asparagine 297 (Asn₂₉₇) of IgG heavy chains is decorated by a diantennary glycan bearing a number of galactose and sialic acid residues on the branches ranging from 0 to 2. In addition, the structure can present core-linked fucose and/or a bisecting GlcNAc. In many inflammatory and autoimmune conditions, as well as in metabolic, cardiovascular, infectious, and neoplastic diseases, the IgG Asn₂₉₇-linked glycan becomes less sialylated and less galactosylated, leading to increased expression of glycans terminating with GlcNAc. These conditions alter also the presence of core-fucose and bisecting GlcNAc. Importantly, similar glycomic alterations are observed in aging. The common condition, shared by the above-mentioned pathological conditions and aging, is a low-grade, chronic, asymptomatic inflammatory state which, in the case of aging, is known as inflammaging. Glycomic alterations associated with inflammatory diseases often precede disease onset and follow remission. The aberrantly glycosylated IgG glycans associated with inflammation and aging can sustain inflammation through different mechanisms, fueling a vicious loop. These include complement activation, Fcγ receptor binding, binding to lectin receptors on antigen-presenting cells, and autoantibody reactivity. The complex molecular bases of the glycomic changes associated with inflammation and aging are still poorly understood.

Glycomics: Immunoglobulin G N-Glycosylation Associated with Mammary Gland Hyperplasia in Women

Mammary gland hyperplasia (MGH) is very common, especially among young and middle-aged women. New diagnostics and biomarkers for MGH are needed for rational clinical management and precision medicine. We report, in this study, new findings using a glycomics approach, with a focus on immunoglobulin G (IgG) N-glycosylation. A cross-sectional study was conducted in a community-based population sample in Beijing, China. A total of 387 participants 40-65 years of age were enrolled in this study, including 194 women with MGH (cases) and 193 women who had no MGH (controls). IgG N-glycans were characterized in the serum by ultra-performance liquid chromatography. The levels of the glycan peaks (GPs) GP2, GP5, GP6, and GP7 were lower in the MGH group compared with the control group, whereas GP14 was significantly higher in the MGH group (p < 0.05). A predictive model using GP5, GP21, and age was established and a receiver operating characteristic curve analysis was performed. The sensitivity and specificity of the model for MGH was 61.3% and 63.2%, respectively, likely owing to receptor mechanisms and/or inflammation regulation. To the best of our knowledge, this is the first study reporting on an association between IgG N-glycosylation and MGH. We suggest person-to-person variations in IgG N-glycans and their combination with multiomics biomarker strategies offer a promising avenue to identify novel diagnostics and individuals at increased risk of MGH.

Interferon-α alters host glycosylation machinery during treated HIV infection

Background

A comprehensive understanding of host factors modulated by the antiviral cytokine interferon-α (IFNα) is imperative for harnessing its beneficial effects while avoiding its detrimental side-effects during HIV infection. Cytokines modulate host glycosylation which plays a critical role in mediating immunological functions. However, the impact of IFNα on host glycosylation has never been characterized.

Methods

We assessed the impact of pegylated IFNα2a on IgG glycome, as well as CD8⁺ T and NK cell-surface glycomes, of 18 HIV-infected individuals on suppressive antiretroviral therapy. We linked these glycomic signatures to changes in inflammation, CD8⁺ T and NK cell phenotypes, and HIV DNA.

Findings

We identified significant interactions that support a model in which a) IFNα increases the proportion of pro-inflammatory, bisecting GlcNAc glycans (known to enhance FcγR binding) within the IgG glycome, which in turn b) increases inflammation, which c) leads to poor CD8⁺ T cell phenotypes and poor IFNα-mediated reduction of HIV DNA. Examining cell-surface glycomes, IFNα increases levels of the immunosuppressive GalNAc-containing glycans (T/Tn antigens) on CD8⁺ T cells. This induction is associated with lower HIV-gag-specific CD8⁺ T cell functions. Last, IFNα increases levels of fucose on NK cells. This induction is associated with higher NK functions upon K562 stimulation.

Interpretation

IFNα causes host glycomic alterations that are known to modulate immunological responses. These alterations are associated with both detrimental and beneficial consequences of IFNα. Manipulating host glycomic interactions may represent a strategy for enhancing the positive effects of IFNα while avoiding its detrimental side-effects.

Funding

NIH grants R21AI143385, U01AI110434.

A Predictive Model Using N-Glycan Biosignatures for Clinical Diagnosis of Early Hepatocellular Carcinoma Related to Hepatitis B Virus

Early diagnosis of hepatic cancer is a major public health challenge. While changes in serum N-glycans have been observed as patients progress from liver fibrosis/cirrhosis to hepatocellular carcinoma (HCC), the predictive performance of N-glycans is yet to be determined for HCC early diagnosis as well as differential diagnosis from liver fibrosis/cirrhosis. In a total sample of 247 patients with hepatitis B virus-related liver disease, we characterized and compared the serum N-glycans in very early/early and intermediate/advanced stages of HCC and those with liver fibrosis/cirrhosis. Additionally, we performed a retrospective timeline analysis of the serum N-glycans 6 and 12 months before a diagnosis of the very early/early stage of HCC (EHCC). A predictive model was built, named hereafter as Glycomics-EHCC, incorporating the glycan peaks (GPs) 1, 2, and 4. The model showed a larger area under the receiver operating characteristic curve compared with a traditional model with the α-fetoprotein (0.936 vs. 0.731, respectively). The Glycomics-EHCC model had a sensitivity of 84.6% and specificity of 85.0% at a cutoff value of -0.39 to distinguish EHCC from liver fibrosis/cirrhosis. Moreover, the Glycomics-EHCC model was able to forecast a future EHCC diagnosis with a sensitivity and specificity over 90% and 85%, respectively, using the serum N-glycan biosignatures 6 or 12 months earlier when the patients were suffering from liver fibrosis/cirrhosis before being diagnosed with EHCC. This serum glycomic biosignature model warrants further clinical studies in independent population samples and offers promise to forecast EHCC and its differential diagnosis from liver fibrosis/cirrhosis.