title: Combined top-down and bottom-up mass spectrometric approach to characterization of biomarkers for renal disease.
abstract: Here we describe a mass spectrometry (MS) approach for biomarker discovery and structural characterization, based on both top-down and bottom-up analyses. Capillary electrophoresis (CE) coupled to electrospray ionization (ESI) time-of-flight (TOF) MS serves to separate and mass-measure the thousands of polypeptides contained in human urine. Statistical analysis of the differences between healthy control samples and patients with focal-segmental glomerulosclerosis, membranous glomerulonephritis, minimal change disease, IgA nephropathy, and diabetic nephropathy validates multiple biomarkers for the control and each of the diseases. To identify those biomarkers, we employ preparative CE, enabling direct infusion ESI MS analysis, followed by sample manipulation and reanalysis where necessary. We show how tandem Fourier transform ion cyclotron resonance (FT-ICR) MS identifies these sometimes large (>8 kDa) biomarkers. Critically, we maintain connectivity between the CE TOF MS data and the ICR data used for biomarker identification.
authors.affiliation: Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, Florida State University, Tallahassee, 32310-4005, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Chalmers
authors.forename: Colin Logan
authors.initials: CL
authors.lastname: Mackay
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Hendrickson
authors.forename: Stefan
authors.initials: S
authors.lastname: Wittke
authors.forename: Michael
authors.initials: M
authors.lastname: Walden
authors.forename: Harald
authors.initials: H
authors.lastname: Mischak
authors.forename: Danilo
authors.initials: D
authors.lastname: Fliser
authors.forename: Ingo
authors.initials: I
authors.lastname: Just
authors.forename: Alan G
authors.initials: AG
authors.lastname: Marshall
mesh_terms: D000595:Amino Acid Sequence; D015415:Biomarkers / Q000652:urine; D019075:Electrophoresis, Capillary; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007674:Kidney Diseases / Q000652:urine*; D013058:Mass Spectrometry / Q000295:instrumentation* / Q000379:methods*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009862:Online Systems; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D015415:Biomarkers