title: Enhanced detection of CNS cell secretome in plasma protein-depleted cerebrospinal fluid.
abstract: Human cerebrospinal fluid (CSF) proteome is actively investigated to identify relevant biomarkers and therapeutic targets for neurological disorders. Approximately 80% of CSF proteome originate from plasma, yielding a high dynamic range in CSF protein concentration and precluding identification of potential biomarkers originating from CNS cells. Here, we have adapted the most complete multiaffinity depletion method available to remove 20 abundant plasma proteins from a CSF pool originating from patients with various cognitive disorders. We identified 622 unique CSF proteins in immunodepleted plus retained fractions versus 299 in native CSF, including 22 proteins hitherto not identified in CSF. Parallel analysis of neuronal secretome identified 34 major proteins secreted by cultured cortical neurons (cell adhesion molecules, proteins involved in neurite outgrowth and axonal guidance, modulators of synaptic transmission, proteases and protease inhibitors) of which 76% were detected with a high confidence in immunodepleted CSF versus 50% in native CSF. Moreover, a majority of proteins previously identified as secretory products of choroid plexus cells or astrocytes were detected in immunodepleted CSF. Hence, removal of 20 major plasma proteins from CSF improves detection of brain cell-derived proteins in CSF and should facilitate identification of relevant biomarkers in CSF proteome profiling analyses.
authors.affiliation: Centre National de la Recherche Scientifique, UMR 5203, Institut de Genomique Fonctionnelle, Montpellier, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Thouvenot
authors.forename: Serge
authors.initials: S
authors.lastname: Urbach
authors.forename: Christelle
authors.initials: C
authors.lastname: Dantec
authors.forename: Joël
authors.initials: J
authors.lastname: Poncet
authors.forename: Martial
authors.initials: M
authors.lastname: Séveno
authors.forename: Edith
authors.initials: E
authors.lastname: Demettre
authors.forename: Patrick
authors.initials: P
authors.lastname: Jouin
authors.forename: Jacques
authors.initials: J
authors.lastname: Touchon
authors.forename: Joël
authors.initials: J
authors.lastname: Bockaert
authors.forename: Philippe
authors.initials: P
authors.lastname: Marin
mesh_terms: D015415:Biomarkers / Q000737:chemistry / Q000378:metabolism; D001798:Blood Proteins / Q000134:cerebrospinal fluid / Q000737:chemistry / Q000378:metabolism; D002478:Cells, Cultured; D002490:Central Nervous System / Q000737:chemistry*; D002540:Cerebral Cortex / Q000166:cytology; D002555:Cerebrospinal Fluid / Q000737:chemistry*; D006801:Humans; D008969:Molecular Sequence Data; D009474:Neurons / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D020543:Proteome / Q000032:analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D015415:Biomarkers; D001798:Blood Proteins; D020543:Proteome