Cerebrospinal fluid (CSF) has become one of the most frequently used biological medium for physiological studies for
neurological disorders due to its proximity to the brain and clinical availability; however, before undertaking a rational approach to
biomarker discovery or diagnostics, it is crucial to understand the underlying characteristics of CSF
proteome in subpopulations. In this study, we examined the differential expression of
proteins in pooled male and female CSF utilizing isobaric tags for relative and absolute quantification (iTRAQ)
reagents after the depletion of six high abundant
proteins using a multiple affinity removal system (MARS). A total of 219
proteins were identified (95% confidence level), and 12
proteins showed difference in expression levels. Eleven out of 12 differentially expressed
proteins showed ratios of male/female between 1.15 and 1.29 (duplicate average), indicating a remarkable similarity between male and female CSF. One notable exception was the slightly lower expression level of
ceruloplasmin (ferroxidase) in male CSF (0.81), a
copper containing
protein that catalyzes the conversion of ferrous
iron to ferric
iron with
antioxidant properties. We also examined the levels of
ceruloplasmin in each individual patient sample which constituted the pooled CSF using Western blot analysis which confirmed the lower expression levels of
ceruloplasmin in male CSF.