Enhanced detection of CNS cell secretome in plasma protein-depleted cerebrospinal fluid.
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.
Thouvenot
Eric
E
Centre National de la Recherche Scientifique, UMR 5203, Institut de Genomique Fonctionnelle, Montpellier, France.
Urbach
Serge
S
Dantec
Christelle
C
Poncet
Joël
J
Séveno
Martial
M
Demettre
Edith
E
Jouin
Patrick
P
Touchon
Jacques
J
Bockaert
Joël
J
Marin
Philippe
P
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
D015415:Biomarkers; D001798:Blood Proteins; D020543:Proteome