title: Label-free quantitative proteomics reveals differentially regulated proteins influencing urolithiasis.
abstract: Urinary proteins have been implicated as inhibitors of kidney stone formation (urolithiasis). As a proximal fluid, prefiltered by the kidneys, urine is an attractive biofluid for proteomic analysis in urologic conditions. However, it is necessary to correct for variations in urinary concentration. In our study, individual urine samples were normalized for this variation by using a total protein to creatinine ratio. Pooled urine samples were compared in two independent experiments. Differences between the urinary proteome of stone formers and nonstone-forming controls were characterized and quantified using label-free nano-ultraperformance liquid chromatography high/low collision energy switching analysis. There were 1063 proteins identified, of which 367 were unique to the stone former groups, 408 proteins were unique to the control pools, and 288 proteins were identified for comparative quantification. Proteins found to be unique in stone-formers were involved in carbohydrate metabolism pathways and associated with disease states. Thirty-four proteins demonstrated a consistent >twofold change between stone formers and controls. For ceruloplasmin, one of the proteins was shown to be more than twofold up-regulated in the stone-former pools, this observation was validated in individuals by enzyme-linked immunosorbent assay. Moreover, in vitro crystallization assays demonstrated ceruloplasmin had a dose-dependent increase on calcium oxalate crystal formation. Taken together, these results may suggest a functional role for ceruloplasmin in urolithiasis.
authors.affiliation: Central Proteomics Facility, Henry Wellcome Building for Molecular Physiology, Nuffield Department of Medicine, Roosevelt Drive, University of Oxford, OX3 7BN, UK. Polacco@cgl.ucsf.edu
authors.forename: C A
authors.initials: CA
authors.lastname: Wright
authors.forename: S
authors.initials: S
authors.lastname: Howles
authors.forename: D C
authors.initials: DC
authors.lastname: Trudgian
authors.forename: B M
authors.initials: BM
authors.lastname: Kessler
authors.forename: J M
authors.initials: JM
authors.lastname: Reynard
authors.forename: J G
authors.initials: JG
authors.lastname: Noble
authors.forename: F C
authors.initials: FC
authors.lastname: Hamdy
authors.forename: B W
authors.initials: BW
authors.lastname: Turney
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000581:Amidohydrolases / Q000652:urine; D000595:Amino Acid Sequence; D015415:Biomarkers / Q000378:metabolism / Q000652:urine; D002129:Calcium Oxalate / Q000737:chemistry; D016022:Case-Control Studies; D002570:Ceruloplasmin / Q000737:chemistry / Q000652:urine*; D003460:Crystallization; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000737:chemistry; D011507:Proteinuria / Q000378:metabolism / Q000652:urine*; D020543:Proteome / Q000737:chemistry / Q000378:metabolism*; D040901:Proteomics; D053719:Tandem Mass Spectrometry; D052878:Urolithiasis / Q000378:metabolism / Q000652:urine*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; D020543:Proteome; D002129:Calcium Oxalate; D002570:Ceruloplasmin; D000581:Amidohydrolases; C019946:creatininase