Glycosylation of Human Plasma Clusterin Yields a Novel Candidate Biomarker of Alzheimer's Disease.
Specific glycosylated peptides of clusterin are found associated with hippocampal atrophy. The glycosylation of clusterin from human plasma was comprehensively analyzed and characterized using mass spectrometry (MS)-based glycoproteomics analysis. All six known N-glycosylation sites are covered, three in the alpha subunit (α64N, α81N and α123N) and three in the beta subunit (β64N, β127N, and β147N). More detailed structural characterization of clusterin glycopeptides was also performed, demonstrating the presence of glycosylated peptides and their corresponding glycans. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), we have determined the differences in the glycoforms associated at each of the different glycosylation sites in plasma clusterin obtained from subjects of low hippocampal atrophy (n = 13) and high hippocampal atrophy (n = 14). In our pilot study, the β64N site shows the most significant regulations between clinical groups. Eight β64N glycoforms are significantly reduced in patients with high atrophy compared with those with low atrophy, which demonstrates the utility of clusterin isoforms as diagnostic and prognostic Alzheimer's disease (AD) markers. These results provide a novel and robust workflow suitable for rapid verification of specific clusterin glycoforms with utility as AD biomarkers.
Proteome Sciences plc , Coveham House, Downside Bridge Road, Cobham KT11 3EP, United Kingdom.
Hui-Chung
HC
Liang
Proteome Sciences plc , Coveham House, Downside Bridge Road, Cobham KT11 3EP, United Kingdom.
Claire
C
Russell
Proteome Sciences plc , Coveham House, Downside Bridge Road, Cobham KT11 3EP, United Kingdom.
Vikram
V
Mitra
Department of Old Age Psychiatry, Institute of Psychiatry, King's College London , De Crespigny Park, London SE5 8AF, United Kingdom.
Raymond
R
Chung
Department of Old Age Psychiatry, Institute of Psychiatry, King's College London , De Crespigny Park, London SE5 8AF, United Kingdom.
Abdul
A
Hye
Department of Old Age Psychiatry, Institute of Psychiatry, King's College London , De Crespigny Park, London SE5 8AF, United Kingdom.
Chantal
C
Bazenet
Department of Psychiatry, Medical Sciences Division, University of Oxford, Warneford Hospital , Oxford OX3 7JX, United Kingdom.
Simon
S
Lovestone
Proteome Sciences plc , Coveham House, Downside Bridge Road, Cobham KT11 3EP, United Kingdom.
Ian
I
Pike
Proteome Sciences plc , Coveham House, Downside Bridge Road, Cobham KT11 3EP, United Kingdom.
Malcolm
M
Ward
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood* / Q000473:pathology; D000595:Amino Acid Sequence; D001284:Atrophy / Q000097:blood; D015415:Biomarkers / Q000097:blood* / Q000378:metabolism; D051152:Clusterin / Q000097:blood* / Q000378:metabolism; D003072:Cognition Disorders / Q000097:blood; D005260:Female; D006031:Glycosylation; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010865:Pilot Projects; D053719:Tandem Mass Spectrometry
D015415:Biomarkers; C495242:CLU protein, human; D051152:Clusterin
Alzheimer’s disease; and biomarker; clusterin; glycosylation; hippocampal atrophy; mass spectrometry; selected reaction monitoring