Quantitative analysis of the intra- and inter-individual variability of the normal urinary proteome.
Urine is a readily and noninvasively obtainable body fluid. Mass spectrometry (MS)-based proteomics has shown that urine contains thousands of proteins. Urine is a potential source of biomarkers for diseases of proximal and distal tissues but it is thought to be more variable than the more commonly used plasma. By LC-MS/MS analysis on an LTQ-Orbitrap without prefractionation we characterized the urinary proteome of seven normal human donors over three consecutive days. Label-free quantification of triplicate single runs covered the urinary proteome to a depth of more than 600 proteins. The median coefficient of variation (cv) of technical replicates was 0.18. Interday variability was markedly higher with a cv of 0.48 and the overall variation of the urinary proteome between individuals was 0.66. Thus technical variability in our data was 7.5%, whereas intrapersonal variability contributed 45.5% and interpersonal variability contributed 47.1% to total variability. Determination of the normal fluctuation of individual urinary proteins should be useful in establishing significance thresholds in biomarker studies. Our data also allowed definition of a common and abundant set of 500 proteins that were readily detectable in all studied individuals. This core urinary proteome has a high proportion of secreted, membrane, and relatively high-molecular weight proteins.
Department for Proteomics and Signal Transduction at the Max-Planck Institute of Biochemistry, Martinsried, Germany.
Nagarjuna
N
Nagaraj
Matthias
M
Mann
D002853:Chromatography, Liquid; D019295:Computational Biology; D006801:Humans; D010446:Peptide Fragments / Q000032:analysis / Q000378:metabolism; D011506:Proteins / Q000032:analysis / Q000378:metabolism; D011507:Proteinuria / Q000652:urine*; D020543:Proteome / Q000032:analysis* / Q000378:metabolism; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D053719:Tandem Mass Spectrometry; D014556:Urine / Q000737:chemistry*
D010446:Peptide Fragments; D011506:Proteins; D020543:Proteome