Endogeneous peptide profiling of cerebrospinal fluid by MALDI-TOF mass spectrometry: Optimization of magnetic bead-based peptide capture and analysis of preanalytical variables

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Abstract

Cerebrospinal fluid (CSF) perfuses the brain and spinal cord. CSF contains peptides and proteins important for brain physiology and potentially also relevant to brain pathology. High-throughput endogeneous peptide profiling by MS is an emerging approach for disease diagnosis and biomarker discovery. A magnetic bead-based method for off-line serum peptide capture coupled to MALDI-TOF-MS has been introduced recently. In this study, we optimize the peptide capture method for profiling of CSF and investigate the effect of a number of preanalytical variables. The CSF profiles contain ∼100 reliably detected peptides at m/z 800-4000 with reproducible ion intensities (average 7% CV). The investigated preanalytical variables include: time at room temperature (RT) before storage, storage temperature, freeze-thawing cycles, and blood contamination. The CSF peptidome (<20 kDa) is relatively stable and can withstand a few hours at RT and several freeze-thaw cycles. Several peptides sensitive to storage at -20°C, including Cystatin C, were assigned based on mass or identified by MS/MS. Hemoglobin α and β chains were detected in blood contaminated samples, at levels invisible to the eye (0.01%). These peptides may be used for quality control in a MALDI-TOF-MS screening strategy to select high quality samples for indepth proteomics analysis in disease studies.

Original languageEnglish
Pages (from-to)1385-1392
Number of pages8
JournalProteomics - Clinical Applications
Volume1
Issue number11
DOIs
Publication statusPublished - Nov 2007

Keywords

  • C18 magnetic dynabeads
  • CSF
  • MALDI-TOF-MS
  • Preanalytical variables
  • Reproducibility

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