A Look at the Basis for Glycosylation Clocks to Measure Biological Age
Immunoglobulins are the molecules making up antibodies. Post-translational modification of immunoglobulin molecules changes their function, and is a complex aspect of this portion of the immune system, altering the character of immune responses. The post-translational modification of glycosylation has been shown to shift in characteristic ways in immunogloblins with age. Analysis of these changes has given rise to the GlycanAge clock for the measurement of biological age. Here, researchers review what is known of these age-related changes and their relevance to specific aspects of immune aging.
Immunoglobulin G (IgG) is an important serum glycoprotein and a major component of antibodies. Glycans on IgG affect the binding of IgG to the Fc receptor or complement C1q, which in turn affects the biological activity and biological function of IgG. Altered glycosylation patterns on IgG emerge as important biomarkers in the aging process and age-related diseases. Key aging-related alterations observed in IgG glycosylation include reductions in galactosylation and sialylation, alongside increases in agalactosylation, and bisecting GlcNAc.
Understanding the role of IgG glycosylation in aging-related diseases offers insights into disease mechanisms and provides opportunities for the development of diagnostic and therapeutic strategies. This review summarizes five aspects of IgG: an overview of IgG, IgG glycosylation, IgG glycosylation with inflammation mediation, IgG glycan changes with normal aging, as well as the relevance of IgG glycan changes to aging-related diseases. This review provides a reference for further investigation of the regulatory mechanisms of IgG glycosylation in aging-related diseases, as well as for evaluating the potential of IgG glycosylation changes as markers of aging and aging-related diseases.