Exercise and exercise-induced weight loss have a beneficial effect on overall health, including positive effects on molecular pathways associated with immune function, especially in overweight ...individuals. The main aim of our study was to assess how energy deprivation (i.e., "semi-starvation") leading to substantial fat mass loss affects the immune system and immunosuppression in previously normal weight individuals. Thus, to address this hypothesis, we applied a high-throughput systems biology approach to better characterize potential key pathways associated with immune system modulation during intensive weight loss and subsequent weight regain. We examined 42 healthy female physique athletes (age 27.5 ± 4.0 years, body mass index 23.4 ± 1.7 kg/m
) volunteered into either a diet group (
= 25) or a control group (
= 17). For the diet group, the energy intake was reduced and exercise levels were increased to induce loss of fat mass that was subsequently regained during a recovery period. The control group was instructed to maintain their typical lifestyle, exercise levels, and energy intake at a constant level. For quantification of systems biology markers, fasting blood samples were drawn at three time points: baseline (
), at the end of the weight loss period (
21.1 ± 3.1 weeks after
), and at the end of the weight regain period (
18.4 ± 2.9 weeks after
). In contrast to the control group, the diet group showed significant (false discovery rate <0.05) alteration of all measured immune function parameters-white blood cells (WBCs), immunoglobulin G glycome, leukocyte transcriptome, and cytokine profile. Integrative omics suggested effects on multiple levels of immune system as dysregulated hematopoiesis, suppressed immune cell proliferation, attenuated systemic inflammation, and loss of immune cell function by reduced antibody and chemokine secretion was implied after intense weight loss. During the weight regain period, the majority of the measured immune system parameters returned back to the baseline. In summary, this study elucidated a number of molecular pathways presumably explaining immunosuppression in individuals going through prolonged periods of intense training with low-energy availability. Our findings also reinforce the perception that the way in which weight loss is achieved (i.e., dietary restriction, exercise, or both) has a distinct effect on how the immune system is modulated.
•IgG glycans represent an interface between genes and environment.•IgG glycome composition changes in various physiological and pathological states.•IgG glycans are an excellent biomarker of ...biological age.•Glycosylation of IgG modulates its effector functions.•Knowledge of IgG glycosylation can improve disease biomarkers and vaccination and immunotherapy protocols.
The Immunoglobulin G (IgG) glycome is well known for its heterogeneity and shows a significant degree of variation within populations. IgG glycome composition is influenced both by genes and by environment, making it an excellent biomarker of a person's general health state, i.e. biological age. IgG glycosylation appears to be highly regulated, both during homeostasis and in cases of its disturbance. Changes in IgG glycosylation patterns have been observed in aging and in various diseases. Differential IgG glycosylation is known to modulate IgG effector functions and is involved in disease development and progression, representing both a predisposition and a functional mechanism involved in disease pathology. This makes IgG glycosylation analysis a promising add-on to improve existing disease biomarkers.
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.
-glycans have shown great promise as biomarkers in different diseases, specifically those involving inflammatory changes. To assess the changes in the
-glycosylation of the plasma proteins and IgG in atrial fibrillation, we analyzed the
-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
-glycan structure from the plasma
-glycome and six IgG
-glycans, mainly revolving around the presence of bisecting
-acetylglucosamine, that were significantly different between the case and control groups. In addition, four plasma
-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
-glycosylation was extensively associated with the CHA
DS
-VASc score, confirming its previously reported associations with the conditions that make up the score. This is the first study looking at the
-glycosylation patterns in atrial fibrillation and warrants further investigation into the prospect of glycans as biomarkers for atrial fibrillation.
Chronic low back pain (CLBP) is one of the most common medical conditions, ranking as the greatest contributor to global disability and accounting for huge societal costs based on the Global Burden ...of Disease 2010 study. Large genetic and -omics studies provide a promising avenue for the screening, development and validation of biomarkers useful for personalized diagnosis and treatment (precision medicine). Multicentre studies are needed for such an effort, and a standardized and homogeneous approach is vital for recruitment of large numbers of participants among different centres (clinical and laboratories) to obtain robust and reproducible results. To date, no validated standard operating procedures (SOPs) for genetic/-omics studies in chronic pain have been developed. In this study, we validated an SOP model that will be used in the multicentre (5 centres) retrospective "PainOmics" study, funded by the European Community in the 7th Framework Programme, which aims to develop new biomarkers for CLBP through three different -omics approaches: genomics, glycomics and activomics. The SOPs describe the specific procedures for (1) blood collection, (2) sample processing and storage, (3) shipping details and (4) cross-check testing and validation before assays that all the centres involved in the study have to follow. Multivariate analysis revealed the absolute specificity and homogeneity of the samples collected by the five centres for all genetics, glycomics and activomics analyses. The SOPs used in our multicenter study have been validated. Hence, they could represent an innovative tool for the correct management and collection of reliable samples in other large-omics-based multicenter studies.
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 fragment crystallizable (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.
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.
Graphical Abstract
Purpose of Review
Protein glycosylation has been observed to associate with different diseases, including cardiovascular diseases (CVDs). Most of these observations are related to
O
-glycosylation, ...yet
N
-glycosylation changes have recently gained more attention.
Recent Findings
N
-Glycosylation alterations are associated with CVDs and play an important role in disease development: directly and indirectly through risk factors associated with the disease.
Summary
The changes of
N
-glycosylation are a new risk factor for CVDs and have significant biomarker potential for disease development, progression, and therapy monitoring.
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.
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•Single-nucleus RNA-seq of adult hippocampal-entorhinal cells in human, monkey, and pig•Transcriptomic signatures of adult neurogenesis in mouse, pig, and monkey but not human•Excitatory neuron diversification delineates transitions from 3- to 6-layered cortex•METTL7B defines subregion-specific excitatory neurons and astrocytes in primates
Using snRNA-seq of the adult human, macaque, and pig hippocampal-entorhinal system, Franjic et al. defined shared and divergent cell type features, like primate-specific expression of METTL7B in some excitatory neurons and astrocytes. They also identified robust transcriptomic and histologic signatures of neurogenesis in the mouse, pig, and macaque but not humans.
Antibodies are known to have an important role in the development of rheumatoid arthritis (RA), one of the most prevalent chronic inflammatory diseases which primarily involves the joints. Most RA ...patients develop autoantibodies against immunoglobulin G (IgG) and changes in IgG glycosylation have been associated with RA. We undertook this study to determine whether altered IgG glycosylation precedes the disease diagnosis. We studied IgG glycosylation in RA in two prospective cohorts (N = 14,749) by measuring 28 IgG glycan traits in 179 subjects who developed RA within 10-years follow-up and 358 matched controls. Ultra-performance liquid chromatography method based on hydrophilic interactions (HILIC-UPLC) was used to analyse IgG glycans. Future RA diagnosis associated with traits related to lower galactosylation and sialylation of IgG when comparing the cases to the matched controls. In RA cases, these traits did not correlate with the time between being recruited to the study and being diagnosed with RA (median time 4.31 years). The difference in IgG glycosylation was relatively stable and present years before diagnosis. This indicates that long-acting factors affecting IgG glycome composition are among the underlying mechanisms of RA and that decreased galactosylation is a pre-existing risk factor involved in the disease development.
•Future diagnosis of rheumatoid arthritis is associated with lower galactosylation of IgG.•IgG glycosylation alterations are present years before diagnosis.•Glycosylation is a pre-existing risk factor involved in the disease development.
Extraction of N-glycans from intact tissue presents a unique set of challenges which makes it a relatively laborious and time-consuming process in comparison to other sample types, such as plasma. ...Here we present an approach designed for the extraction, purification, and labeling of free N-glycans from brain tissue. Using this method, up to 16 samples can be processed at once which translates to an output of 48 samples per week when rounds of extraction are staggered. Moreover, although intended for brain tissue, the method could easily be adapted to other tissue types as well. The protocol involves several stages. First, the tissue is homogenized and total proteins are isolated using chloroform-methanol extraction. The proteins are then deglycosylated using the Peptide N-Glycosidase F (PNGase F) enzyme in a reaction lasting two days. The released N-glycans are subsequently cleaned up from the reaction mixture using a centrifugal filter device and dried overnight. Next, the N-glycans are resuspended, labeled with 2-aminobenzamide (2-AB) and once again cleaned up using a filter plate. The purified N-glycans are released from the filter using ultrapure water and are then ready for analysis by for hydrophilic interaction ultra performance liquid chromatography (HILIC-UPLC).
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