|Unique protein groups identified in a series of one-dimensional gel fractions from either crude CSF (dotted line) or the first eluate from samples treated with the NH2 library (solid line).
Cerebrospinal fluid (CSF) contains many proteins of neural origin and is often known as a biochemical window into the brain. Therefore, CSF is an ideal source in the search for biomarkers of neurological diseases, if the proteomic challenge of characterizing a biological fluid with a very wide concentration range of proteins can be overcome. In this study, the researchers used a combinatorial peptide ligand library bound to porous beads to reduce the dynamic range of protein concentrations in CSF and progressively enrich minor protein species. With this approach, they managed to uncover a host of previously hidden CSF proteins; of the 1,212 CSF proteins they identified from pooled samples using liquid chromatography-tandem mass spectrometry, only 745 were detected after peptide library treatment. When the protocol was optimized to work with individual low-volume samples, as would be the case in any clinical application, the researchers found that this miniaturized approach was still reproducible and effective at enriching low concentration proteins, making it a feasible strategy for analyzing neurological diseases.
In-depth Exploration of Cerebrospinal Fluid by Combining Peptide Ligand Library Treatment and Label-free Protein Quantification
Emmanuelle Mouton-Barbosa, Florence Roux-Dalvai, David Bouyssié, François Berger, Eric Schmidt, Pier Giorgio Righetti, Luc Guerrier, Egisto Boschetti, Odile Burlet-Schiltz, Bernard Monsarrat and Anne Gonzalez de Peredo
Mol. Cell. Proteomics, published online Jan. 21, 2010