Discovery of Glyco-biomarkers for Diabetes and Complications in Diabetes

  • Di Wu

    Student thesis: Doctoral ThesisDoctor of Philosophy


    Diabetes mellitus is a group of metabolic diseases characterized in disordered blood glucose levels with many altered genes, proteins and metabolites. The chronic hyperglycemia in diabetes damages organ systems and makes the diabetic patients vulnerable to one or more complications. The onset of diabetes and complications in diabetes are estimated to occur 5 to 10 years before the clinical diagnosis. The early diagnosis of diabetes prevents the damage and pathological progress of diabetes and complications in diabetes. The central hypothesis of this study was that the protein N-glycosylation pathway in diabetes might be influenced by elevated hexosamine flux in diabetes elevating sugar nucleotide levels. This, in turn, might affect the N-glycan branching pathway and result in detectable changes in plasma glycoprotein glycoforms.
    The aim of the study was to discover potential glyco-biomarkers for diabetes and complication in diabetes. Mass spectrometry based glycomic quantification was performed to look for alterations in N-glycan profiles between normal and diabetic plasma samples. Fucosylated N-glycans and intersected N-glycans were found to be up-regulated in diabetes with statistical significance. The elevated fucosylation in diabetes was verified at the glycosylation site level by quantitative Aleuria aurantia lectin (AAL) pull-down experiments. Fucosylated fetuin-A and α-1-acid glycoprotein were selected as candidate glyco-biomarkers. A lectin ELISA using F(abʹ)2 fragments as capture antibody was developed to validate the fucosylation changes by screening 20 normal and 20 diabetic patient plasma samples. We conclude that the fucosylation level of fetuin-A is a potential glyco-biomarker for diabetes. Additional work is necessary to see whether this glyco-biomarker correlates with any pathological complications of diabetes.
    Date of Award2015
    Original languageEnglish
    SupervisorMichael Ferguson (Supervisor)

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