Change in N-Glycosylation of Plasma Proteins in Japanese Semisupercentenarians

Abstract

An N-glycomic analysis of plasma proteins was performed in Japanese semisupercentenarians (SSCs) (mean 106.7 years), aged controls (mean 71.6 years), and young controls (mean 30.2 years) by liquid chromatography/mass spectrometry (LC/MS) using a graphitized carbon column. Characteristic N-glycans in SSCs were discriminated using a multivariate analysis; orthogonal projections to latent structures (O-PLS). The results obtained showed that multi-branched and highly sialylated N-glycans as well as agalacto- and/or bisecting N-glycans were increased in SSCs, while biantennary N-glycans were decreased. Since multi-branched and highly sialylated N-glycans have been implicated in anti-inflammatory activities, these changes may play a role in the enhanced chronic inflammation observed in SSCs. The levels of inflammatory proteins, such as CRP, adiponectin, IL-6, and TNF-α, were elevated in SSCs. These results suggested that responses to inflammation may play an important role in extreme longevity and healthy aging in humans. This is the first study to show that the N-glycans of plasma proteins were associated with extreme longevity and healthy aging in humans.

Fig 1. Typical N-glycan profile from plasma proteins in SSC.

Deduced N-glycan structures were added to the base peak chromatogram of the SSC sample. Top and bottom charts represent the positive and negative ion modes, respectively. Vertical axis, relative abundance; horizontal axis, retention time; blue square, N-acetylglucosamine; yellow circle, galactose; green circle, mannose; purple diamond, N-acetylneuraminic acid; red triangle, fucose.

Fig 2. Score plot and loading plot obtained by PCA or O-PLS.

(A) A PCA score plot of young controls (shadowed), aged controls (opened), and SSCs (closed) (R2X[1] = 0.329635; R2X[2] = 0.201184; Ellipse: Hotelling T2 (95%)) using the peak area ratios of each N-glycan to the total peak area of all identified N-glycans. (B) An O-PLS score plot between young controls (shadowed), aged controls (opened), and SSCs (closed). R2X [1] = 0.295051, R2X [XSide Comp. 1] = 0.106066, Ellipse: Hotelling T2 (95%) (C) A loading plot with jack-knifed confidence intervals by O-PLS. The pq[1] value is the weight that combines the X and Y variables. The error bar indicates the standard error (SE) of pq[1] values obtained from 16 samples independently. Glycan compositions were deduced by the accurate mass. Numbers in parentheses indicate isomers. “N” or “P” in parentheses indicates the data obtained from the negative or positive ion mode, respectively. Closed and shadowed columns represent [pq1] / SE > 1.5 and < 1.5, respectively. Row data were summarized in S2 Table. Hex, hexose; HexNAc, N-acetylhexosamine; NeuNAc, N-acetylneuraminic acid; dHex, deoxyhexose; NH₄, ammonium.

Fig 3. Deduced structures of characteristic N-glycans in SSCs.

The number of the N-glycan corresponded to Table 1. No. 1~14 were increased and No. 15~18 were decreased in SSCs, respectively. blue square, N-acetylglucosamine; yellow circle, galactose; green circle, mannose; purple diamond, N-acetylneuraminic acid; red triangle, fucose.