Plasma protein N-glycan profiles are associated with calendar age, familial longevity and health

Abstract

The development of medical interventions for the preservation of disease-free longevity would be facilitated by markers that predict healthy aging. Altered protein N-glycosylation patterns have been found with increasing age and several disease states. Here we investigate whether glycans derived from the total glycoprotein pool in plasma mark familial longevity and distinguish healthy from unhealthy aging. Total plasma N-glycan profiles of 2396 middle aged participants in the Leiden Longevity Study (LLS) were obtained by glycan release, labeling, and subsequent HPLC analysis with fluorescence detection. After normalization and batch correction, several regression strategies were applied to evaluate associations between glycan patterns, familial longevity, and healthy aging. Two N-glycan features (LC-7 and LC-8) were identified to be more abundant in plasma of the offspring of long-lived individuals as compared to controls. These results were not confounded by the altered lipid status or glucose homeostasis of the offspring. Furthermore, a decrease in levels of LC-8 was associated with the occurrence of myocardial infarction (p = 0.049, coefficient = -0.065), indicating that plasma glycosylation patterns do not only mark familial longevity but may also reflect healthy aging. In conclusion, we describe two glycan features, of which increased levels mark familial longevity and decreased levels of one of these features mark the presence of cardiovascular disease.

Human Plasma N-glycosylation as Analyzed by Matrix-Assisted Laser Desorption/Ionization-Fourier Transform Ion Cyclotron Resonance-MS Associates with Markers of Inflammation and Metabolic Health

“…In doing so, we have confirmed expectations from literature by showing a decrease of galactosylation and increase in bisection of diantennary fucosylated glycans with increasing age (59 -61), and by men having a higher tri-and tetraantennary fucosylation and lower bisection than women (62,63). Adjusting for the age and sex effects as well as the literature-reported interaction of age and sex (18,21), we proved additional associations between clinical markers for metabolic health/inflammation and plasma N-glycosylation characteristics including antennarity, sialylation, bisection, and galactosylation of various diantennary subgroups, and the size of high-mannose species.…”

“…The latter is a peculiar absence, as plasma N-glycosylation analysis of the same cohort by HPLC had revealed two chromatographic peaks to be predictors of the phenotype (18). Reasons for this lack of biological reproduction may include the measurement error (HPLC tends to provide more robust measurements than mass spectrometry) (71), the chromatographic peaks representing a culmination of multiple mass spectrometric compositions that are not individually significant, the previous findings being incidental, or the inability of mass spectrometry to separate or detect the responsible analytes.…”

“…Previous studies of suitable size (n Ͼ 200) have performed this to various degrees, finding plasma N-glycans to be highly associated with e.g. age, sex, inflammation, body mass index (BMI), cholesterol and lipid levels (17)(18)(19)(20)(21)(22)(23)(24). However, these studies have either been performed on single proteins, immunoglobulin G (IgG) being a particularly wellstudied example, or predominantly by methods of liquid chromatographic and electrophoretic separation (e.g.…”

A Microarray-Matrix-assisted Laser Desorption/Ionization-Mass Spectrometry Approach for Site-specific Protein N-glycosylation Analysis, as Demonstrated for Human Serum Immunoglobulin M (IgM)*

“…Production of Microarray Chips-Microarrays for Mass Spectrometry (MAMS) were fabricated as described in Urban et al, and Kü ster et al (65,66) In brief, a coated ITO-glass slide (12)(13)(14)(15)(16)(17)(18) Ohm/m 2 , Sigma Aldrich) was structured using a laser ablation system to generate a checkerboard-like array of 2800 hydrophilic sample deposition areas of 300 m diameter and ϳ35 m depth each (720 m center-tocenter distance within one row).…”

“…Determination of the site-specific N-glycosylation pattern of complex proteins is a challenging task and therefore glycosylation is often solely analyzed on released glycan pools (15)(16)(17). Whereas the analysis of released pools is necessary when linkage and positional isomers have to be investigated (18,19), the information obtained is here limited to the carbohydrate portion and does not allow any conclusion on a protein site specific heterogeneity.…”