Protein Changes in Immunodepleted Cerebrospinal Fluid from a Transgenic Mouse Model of Alexander Disease Detected Using Mass Spectrometry

Cerebrospinal fluid (CSF) is a low protein content biological
fluid
with a dynamic range spanning at least 9 orders of magnitude in protein
content and is in direct contact with the brain. A modified IgY-14
immunodepletion treatment was performed to enhance analysis of the
low volumes of CSF that are obtainable from mice. As a model system
in which to test this approach, we utilized transgenic mice that overexpress
the intermediate filament glial fibrillary acidic protein (GFAP).
These mice are models for Alexander disease (AxD), a severe leukodystrophy
in humans. From the CSF of control and transgenic mice we report the
identification of 289 proteins, with relative quantification of 103
proteins. Biological and technical triplicates were performed to address
animal variability as well as reproducibility in mass spectrometric
analysis. Relative quantitation was performed using distributive normalized
spectral abundance factor (dNSAF) spectral counting analysis. A panel
of biomarker proteins with significant changes in the CSF of GFAP
transgenic mice has been identified with validation from enzyme-linked
immunosorbent assay (ELISA) and microarray data, demonstrating the
utility of our methodology and providing interesting targets for future
investigations on the molecular and pathological aspects of AxD.