LAUSR

Serum N-glycans have been reported to be potential diagnostic and therapeutic biomarkers for many diseases and conditions, such as inflammation, fibrosis, and cancer progression. We previously described a method for glycomic analysis of gel-separated serum proteins (FPG). With this methodology, we sought novel glycan biomarkers for non-alcoholic steatohepatitis (NASH) and successfully identified some N-glycans which were significantly elevated in NASH patients compared to non-alcoholic fatty liver patients. Among them, tri-sialylated mono-fucosylated tri-antennary glycan (A3F) of alpha-1 antitrypsin showed the most dynamic change. For rapid identification of N-glycans on the focused proteins, we constructed a simplified method called an immunoprecipitation-glycomics (IPG), where the target proteins were immuno-precipitated with affinity beads and subsequently subjected to glycomic analysis by MALDI-TOF MS. Focusing on alpha-1 antitrypsin and ceruloplasmin as the target proteins, we compared the values of N-glycans determined by FPG and IPG. The quantified values of each N-glycan by these two methods showed a statistically significant correlation, indicating that high throughput and quantitative N-glycomics of targeted proteins can be achieved by the simplified IPG method. Thus, an analytical strategy combining FPG and IPG can be adapted to general biomarker discovery and validation in appropriate disease areas.