Sugar chains called paucimannose glycans rise with age across mouse organs and in senescent cells

Glycosylation, the attachment of sugar chains to proteins, shapes how proteins fold, function, and communicate. Glycan patterns change in many diseases, but it has been unclear whether aging produces glycan changes shared across the body. Finding such a common signature could point to new aging biomarkers.

The team analyzed protein-bound N-glycans in seven mouse samples: serum, brain, lung, heart, liver, skeletal muscle, and kidney. They compared profiles across ages, looking for changes that appeared in more than one tissue. They also examined lysosomal glycosidases that might produce the glycans of interest, and tested cultured senescent cells.

Glycan profiles were strongly organ-specific, but each organ showed age-dependent shifts. The most consistent finding was a rise in paucimannose glycans, truncated N-glycans, across multiple organs, with a significant positive correlation with age. The lysosomal enzymes Hexa and Hexb, potentially involved in making paucimannose glycans, were upregulated in aging lung. Senescent cultured cells likewise showed higher expression of these enzymes and more paucimannose glycans.

These results suggest paucimannose glycans could act as a cross-tissue indicator of cellular and organ aging, and they link glycan remodeling to lysosomal function and cellular senescence. Such a marker might eventually help track biological aging or evaluate interventions.

Important caveats apply. The authors state that a causal role for HEXA/HEXB upregulation in paucimannose formation was not directly tested, so the enzyme link remains correlational. The enzyme upregulation was reported in lung, not in every organ. The work is in mice and cell culture, and based on the abstract alone, details such as sample sizes, sexes, and age groups are unavailable. Human relevance is unestablished.